- Email: [email protected]
Vascular adhesion molecules in oral lichen planus
Vascular adhesion molecules in oral lichen planus Joseph A. Regezi, DDS, MS, a Nusi P. Dekker, MA, b Laurie A. MacPhail, PhD, DMD, b Francina Lozada-Nur, DDS, MS, b Timothy H. McCalmont, MD, c San Francisco, Calif. SCHOOL OF DENTISTRYAND SCHOOL OF MEDICINE, UNIVERSITYOF CALIFORNIA-SAN FRANCISCO
Objective. Because recruitment and retention of lymphoid cells appear to be critical components of the pathogenesis of lichen planus, we have compared the expression and distribution of a panel of vascular adhesion molecules (ELAM-1, P-selectin, ICAM-1, VCAM-1, PECAM-1, CD34) and leukocyte adhesion molecule ligands (LFA-1, Mac-l, VLA4, L-selectin) in biopsies of this disease. Study design. Frozen sections of 12 clinically and histologically confirmed cases of lichen planus and 9 normal control tissues were evaluated immunohistochemically with a standard 1-day avidin-biotin peroxidase technique. Staining intensity of vascular endothelium was evaluated semiquantitatively. Three microvascular zones or compartments were defined and evaluated separately. Results. Generally, different staining patterns were observed in association with the various endothelium-associated adhesion molecules. In normal controls, PECAM was intensely expressed and VCAM-1 was weakly expressed. Intermediate staining was associated with ELAM-1, P-selectin, ICAM-1, and CD34. Staining within the three microvascular compartments frequently showed variations in intensity. In lichen planus, increased staining for ELAM-1, P-selectin, ICAM-1, and VCAM-1 was evident in one or more of the microvascular compartments. In the subepithelial vascular compartment where the infiltrate was the most dense, VCAM-1 appeared to show the greatest positive change. Almost all cells in the lichen planus infiltrates stained positive for ICAM-1, L-selectin, LFA-1, and VLA4, and large numbers of cells also exhibited VCAM-1, PECAM-1, and Mac-1 immunoreactivity. Conclusions. It appears that upregulation of ELAM-1, ICAM-1, and VCAM-1 (especially by endothelial cells in the subepithelial vascular plexus) could play a r01e in the pathogenesis of lichen planus. The expression of leukocyte receptors L-selectin, LFA-1, and VLA4 by most of the cells in the lichen planus infiltrate suggest that these molecules may be responsible for recruitment as well as retention in the active lichen planus lesion. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;81:682-90)
Recruitment of leukocytes to sites of inflammation or immunologic challenge is associated with a cascade of leukocyte-endothelial cell adhesion events that involve molecules from several families (selectins, integrins, immunoglobulin superfamily). The selectins, L-selectin, E-selectin (endothelial leukocyte adhesion molecule, ELAM-1), and P-selectin, whose ligands are cell surface carbohydrates, are believed to be involved i n cell-cell adhesion early in the process of lymphocyte homing. 1-6 Leukocyte-associated molecules from the integrin family are involved in leukocyte adhesion to vascular endothelium. 7, 8 The [3-2 integrins, LFA-1 and Mac-l, are ligands for immunoglobulin supergene family molecule, ICAM-1 (intercellular adhesion molecule). The [3-1 integrin, VLA-4, is a ligand for immunoglobulin supergene aDepartmentof Stomatology, School of Dentistry and Department of Pathology, School of Medicine. bDepartment of Stomatology, School of Dentistry. CDepartment of Pathology, School of Medicine. Received for publication Dec. 28, 1994; returned for revision June 13, 1995; accepted for publication Sept. 14, 1995. Copyright 9 1996 by Mosby-Year Book, Inc. 1079-2104/96/$5.00 + 0 7/14/69408
682
molecule, VCAM-1 (vascular adhesion molecule). Another molecule from the same family, PECAM-1 (platelet endothelial cell adhesion molecule) with an undetermined ligand, is believed to be involved in leukocyte recruitment. Blood vessel-associated CD34, which is not structurally related to any of the aforementioned three molecular families, is also thought to be associated with leukocyte-endothelial cell adhesion. Many of these adhesion molecules are believed to be involved in the retention of these leukocytes in the disease focus. Lichen planus (LP) is characterized microscopically by an intense T-cell infiltrate with large numbers of macrophages and XIIIa+ dendrocytes, located at the interface of epithelium and connective tissue. 9-12 From what is known of leukocyte kinetics in tissue, attraction of these cells to an active disease site would require cytokine-mediated upregulation of adhesion molecules by endothelial cells and expression of receptor molecules by lymphocytes and macrophages: 13-21 Altered endothelial cell expression of ELAM-1, ICAM-1, 22 and VCAM-123 has been reported in oral LP, which indicates a role in disease pathogenesis.
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6
Regezi et al.
683
Table I. Antibodies used to identify vascular adhesion molecules and leukocyte ligands Antigen
CD#
ELAM-1 P-selectin ICAM-1
CD62E CD62 CD54
VCAM-1
CD106
PECAM-l
CD31
CD34 L-selectin LFA-1 Mac-1 VLA4
CD34 CD62L CD1la/18 CD1 lb/18 CD49d
Family
Selectin Selectin Immunoglobulin superfamily Immunoglobulin superfamily Immunoglobulin superfamily -Selectin Integrin Integrin Integrin
Antibody clone,type
Source
Dilution
BBIG-E-6,IgG1 ACI-2, IgG1 BBIG-I1,IgG1
R & D Systems,Minneapolis, Minn. Becton Dickinson, San Jose, Calif. R & D Systems
1:1000 1:50 1:2000
BBIG-VI,IgG1
R & D Systems
1:500
--, IgG1
R & D Systems
1:4000
Becton Dickinson Becton Dickinson Dako, Carpinteria, Calif. R & D Systems Upstate Biotechnology,Lake Placid, N.Y.
1:20 1:100 1:100 1:20 1:200
HPCA-1, IgG1 SK-11, IgG2A MHM23, IgG1 44, IgGl B-5G10, IgGl
Other vascular adhesion molecules, such as P-selectin, PECAM-1, and CD34, which may contribute to recruitment of lymphocytes, 1, 19, 24-26 have not been evaluated in LP. The purpose of this investigation was to compare the expression and distribution of a panel of vascular adhesion molecules (ELAM-1, P-selectin, ICAM-1, VCAM-1, PECAM-1, CD34) of potential importance in LP and to compare results with expression of the same molecules in normal tissue. In addition, the leukocyte adhesion molecule ligands (LFA-1, Mac-l, VLA4, L-selectin) on the cellular infiltrate in LP were also evaluated. MATERIAL AND METHODS Oral biopsy specimens of LP (10 buccal mucosa, 2 gingiva) were divided before processing; half of each specimen was immediately frozen in liquid nitrogen for frozen sections, and half was placed in formalin for paraffin sections. The diagnoses of the 12 clinically acceptable cases of oral LP were confirmed with hematoxylin-eosin sections. Microscopic criteria required for inclusion were hyperkeratosis, basal layer vacuolization, individual basal cell necrosis, and a lymphophagocytic infiltrate limited to the interface of the epithelium and connective tissue. Patients (8 women, 4 men) had a mean age of 50 years (range, 32 to 67 years). Seven patients had oral symptoms described as buming or discomfort; two of this group had associated ulcerations. None of the patients were under active treatment for LP, and none were taking drugs that are known to cause lichenoid reactions. Four patients had LP limited to the buccal mucosae only, and eight had additional sites involved. Normal control tissues consisted of four buccal mucosa specimens from unaffected sites in four of the patients
with LP and five gingival specimens from healthy adults without LP. Immunohistochemical staining was done to evaluate expression of endothelial cell-associated adhesion molecules (ELAM-1, P-selectin, ICAM-1, VCAM-1, PECAM-1, CD34) and leukocyte receptor molecules (L-selectin, LFA-1, M a c - l , VLA4) (Table I). Frozen sections of LP and control sections of normal mucosa were incubated with monoclonal antibodies; paraffinembedded sections were also used to evaluate CD34 expression. A standard 1-day avidin-biotin peroxidase technique (Vectastain, Elite, Vector Laboratory, Buflingame, Calif.) was used. Sections were developed in aminoethylcarbazole and counterstained with M a y e r ' s hematoxylin. Negative controls consisted of tissue sections on which primary antibody was replaced with mouse serum. Staining intensity of vascular endothelium was evaluated semiquantitatively with a staining scale of slight (+), moderate (++), and intense (+++). The various microvascular compartments 27-29 (the capillary loops in the connective tissue papillae, the subepithelial vascular plexus, and the submucosal vascular network) were evaluated separately. Although division of the microvasculature into three compartments was somewhat artificial, it did prove to be practical and useful because endothelial staining was often different in these zones. For leukocyte staining, percentages of positively stained cells were estimated from three representative high power fields.
RESULTS Vascular adhesion molecules in normal mucosa In general the control tissues from buccal mucosa and gingiva gave similar results, although the gingi-
684
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 1996
Regezi et al.
II. S u m m a r y o f general staining results for adhesion m o l e c u l e s in L P (n = 12) and controls (n = 9). G r a d i n g scale indicates staining intensity, 0 = negative, + = slight; ++ = m o d e r a t e , +§ = intense. A l l cases stained at intensity shown unless shown in parentheses (n).
Table
Vascular endothelium
Antigen
Controls
Infiltrate
Lichen planus
Controls
Lichen planus (%)
ELAM-1
A 0 (1), + (8)
A ++
--
--
P-selectin
B + (5), ++ (4) C ++ A 0 (3), + (6)
B + (1), ++ (11) C ++ (5), +++ (7) A +
--
--
ICAM-I*
B + (1), ++ (8) C ++ A ++
B ++ C ++ A +++ B +++
B ++ VCAM-I
PECAM-1
CD34
C ++
C +++
A + B 0 CO A +++ B +++ C +++ A ++
A + (6), ++ (6) B ++ C+ A +++ B +++ C +++ A §
B ++ C ++
B + (6), ++ (6) C ++ --
L-selectin
--
LFA-1
--
--
Mac-1
--
--
VLA4
--
--
++ few cells (9)
++ 90-95I
+ few d e n d r o c y t e s (2)
++ 25-75
++ f e w d e n d r o c y t e s (8)
++ 2 5 - 5 0 t
--
+ few round cells (7) +++ many round cells (9) + few dendrocytes (5) + few dendrocytes (8)t
--
++ 90t +++ 95-100t + 1-50 ++ 90-95t
A, capillary loops in connective tissue papillae. B, vascular plexus in subepithelial connective tissue. C, vascular network in submucosa. *Some keratinocytes positive with antibodies to this antigen. tPositive staining of intraepithelial dendritic cells also noted with antibodies to this antigen.
val s p e c i m e n s s h o w e d slightly increased staining intensity associated with E L A M - 1 and V C A M - 1 . Different staining patterns were o b s e r v e d in association with the various e n d o t h e l i u m - a s s o c i a t e d adhesion m o l e c u l e s (Table II). P E C A M was the m o s t intensely e x p r e s s e d a d h e s i o n molecule; it stained all vessels in the three m u c o s a l microvascular c o m p a r t ments (Fig. 1). V C A M - 1 was the w e a k e s t staining m o l e c u l e tested and was l i m i t e d essentially to endothelial cells in the c a p i l l a r y loops o f the connective tissue papillae. In contrast, E L A M - 1 and P-selectin w e r e either w e a k l y e x p r e s s e d or not e x p r e s s e d in c a p i l l a r y loops but w e r e e v i d e n t in l o w e r level vessels. Staining intensity for I C A M - I and C D 3 4 was intermediate b e t w e e n these t w o extremes. A l t h o u g h C D 3 4 was e v i d e n t in frozen sections, it was m o r e intense and had better contrast in p a r a f f i n - e m b e d d e d sections. C D 3 4 staining was t y p i c a l l y f o u n d on the luminal surface o f e n d o t h e l i a l cells.
Leukocyte adhesion molecules in normal mucosa In submucosa, small numbers o f r o u n d cells with either l y m p h o c y t e or m a c r o p h a g e m o r p h o l o g y stained p o s i t i v e for I C A M - 1 and L-selectin ( T a b l e II). L F A - 1 was r e s p o n s i b l e for staining larger n u m b e r s o f simi l a r l y shaped cells. C o n n e c t i v e tissue dendritic cells in the upper s u b m u c o s a o c c a s i o n a l l y stained p o s i t i v e for V C A M - 1 , P E C A M - 1 , Mac-1, and V L A 4 . In the d e e p submucosa, a s e e m i n g l y different p o p u l a t i o n o f dendritic cells w e r e positive for CD34. Rarely, intraepithelial dendritic cells stained w e a k l y positive for V L A 4 .
Vascular adhesion molecules in lichen planus P E C A M - I a p p e a r e d to be m a x i m a l l y e x p r e s s e d in both L P and controls (Fig. 2). I n c r e a s e d staining for E L A M - 1 , P-selectin, I C A M - 1 , and V C A M - 1 was e v i d e n t in one or m o r e o f the m i c r o v a s c u l a r compartm e n t s (Table II) (Figs. 3-6). O c c a s i o n a l l y the subep-
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6
Regezi et al.
685
Epitherlum
Capillary loops
inCTpapilaeI
Subepithelivascul al aplrexus.<~ 0 '=::=> 0
r
o
Submucosalvascularnetwork.<~ 0 ~ ~
0
0 ~ 0
~
0<:::=:,0 ~) 0 (~ 0
0 Fig. 1. Typical immunohistochemical staining pattern for PECAM-1 in control mucosa illustrates the three microvascular "compartments" that were evaluated.
Fig. 2. Immunohistochemical stains for PECAM-I in LP (A) and control specimens (B). Note that both endothelium and inflammatory cells are positive. (Hematoxylin counterstain; original magnification xl00.) ithelial vascular plexus (within the lymphoid infiltrate) stained less intensely for ELAM-1, P-selectin, and CD34 than the other two vascular compartments. As with normal control sections, CD34 staining was consistently of better quality in formalin-fixed, paraffin-embedded sections. Similar or slightly reduced staining intensity for this molecule was evident on subepithelial vessels within the infiltrate.
Leukocyte adhesion molecules in lichen planus Almost all the cells in all the LP infiltrates stained positive for ICAM-1, L-selectin, LFA-1, and VLA4 (Fig. 7). Large numbers of cells also exhibited VCAM-1, PECAM-1, and Mac-1 immunoreactivity (Table II). Intraepithelial dendritic cells (presumably
Langerhans' cells) exhibited upregulation o f l C A M - 1, PECAM, L-selectin, LFA-1, and VLA4.
Discussion The expression of a series of vascular adhesion molecules is involved in the movement of leukocytes from the vascular system to extracellular spaces. Under normal conditions, subsets of leukocytes that bear the receptors for these molecules, infiltrate specific sites, such as mucosa, where they perform a surveillance function. In inflammatory/immune conditions, upregulation of vascular adhesion molecules is responsible for recruitment and retention of the infiltrates that typify these diseases. Site and disease specificity is believed to be related to endothelial ex-
686
Regezi et al.
ORAL SURGERY ORAL MEDICINEORAL PATHOLOGY June 1996
Fig. 3. Immunohistochemical stain for ELAM-1 shows positive reaction on most submucosal vessels. (Hematoxylin counterstain; original magnification xl00.)
Fig. 4. Stain for P-selectin shows most intense reaction on endothelial cells subjacent to the lymphophagocytic infiltrate. Pale zones between infiltrate (upper half) represent epithelium. (Hematoxylin counterstain; original magnification xlO0.)
pression of a combination of vascular adhesion molecules, which themselves may be regulated by disease-specific cytokines, such as TNFo~, IL-1, and interferon-'y. 16'3~ The site, oral mucosa, and the
disease, LP, would therefore be expected to be characterized by the expression of a specific series of vascular adhesion molecules (and cytokines36), Whether there are vascular adhesion molecules that
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6
Regezi et al.
687
Fig. 5. Immunohistochemical stain for ICAM-1 in LP (A) and control (B). Note the vessels, infiltrate, and parabasal keratinocytes are positive in LP. (Hematoxylin counterstain; original magnification xl00.) are unique to oral mucosa lymphocyte homing has not been determined.
different population of dendritic cells whose origin and function are undetermined.
Adhesion molecules in normal mucosa
Adhesion molecules in lichen planus
In normal oral mucosa, expression of vascular adhesion molecules varies from one microvascular compartment to another. Normally, capillary loop endothelium expresses ICAM- l and VCAM- 1 weakly and PECAM-1 and CD34 more intensely. The epithelium lining the subepithelial vascular plexus, which would include capillaries, arterioles, and venules, expresses all molecules except VCAM-1. Staining of the deeper submucosal vessels also shows no expression of VCAM-1. These regional staining differences of the microvasculature of oral mucosa suggest that there is independent regulation of these molecules, and that normal leukocyte trafficking may be associated with segmental expression of various specific adhesion molecules. The staining results of normal mucosa suggest that cell trafficking is strongly associated with lymphocyte expression of LFA-1 and less so with L-selecfin. Expression by round cells and dendritic cells in connective tissue of several of the adhesion molecules tested is likely related to cell-cell communication as well as site retention. The upper level connective tissue dendritic cells, by virtue of position and morphology, likely represent part of the macrophage-related XIIIa dendrocyte p o p u l a t i o n s The deeper CD34-positive dendritic cells appear to represent a
The recruitment of the characteristic lymphophagocytic infiltrate of LP must be related to endothelial expression of a characteristic type or series of adhesion molecules and the reciprocal expression of specific receptors by circulating lymphocytes and macrophages. A comparison of the results of all vessel-associated molecules show that upregulation of ELAM-1, ICAM-1, VCAM-1, and P-selecfin is important in the maintenance or persistence of LP lesions.14, 22, 23 Endothelial expression of ELAM (Eselecfin) and P-selecfin, adhesion molecules that are operative in early stages of leukocyte-endothelial attachment, may be expressed in LP because of persistent, continuous leukocyte recruitment. Because VCAM-1 is not expressed by neutrophils, this molecule may help select for lymphocytes and macrophages. 38 The upregulation of VCAM-1 was of particular note because the changes were most dramatic in the vessels in which the infiltrate was the most dense. In contrast, the slightly decreased staining for ELAM-1 and P-selectin of vessels in the same location suggests these molecules may be less important than VCAM- 1 for cell recruitment in this microvascular zone. It has been suggested that negative or decreased modulation of CD34 is associated with leukocyte adhesion to endothelium. 25 This could not be
688
Regezi et al.
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 1996
Fig. 6. Immunohistochemical stain for VCAM-1 shows positive reaction on both vessels (arrows) and round ceils. (Hematoxylin counterstain; original magnification xl00.)
Fig. 7. Immunohistochemical stains for leukocyte-associated adhesion molecules in LP shows positive reaction on most cells: A, L-selectin; B, LFA-I: C, VLA-4. (Hematoxylin counterstain; original magnification xlO0.)
confirmed in this study. It is also interesting to note that downregulation of CD34 has been associated with cytokine release in vitro and with graft-versus-host disease, a condition that simulates LP microscopically. 26
PECAM-1, which may be involved in the leukocyte-endothelial adhesion cascade, appears to be constitutively expressed on endothelium and macrophages. The persistent high level of P E C A M expres-
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6 sion in control and disease tissue suggests that in vivo activation is required before this molecule can be of functional significance.24 In addition to its role in heterotypic interaction (leukocyte-endothelial cell), it is believed to function in a homotypic fashion (leukocyte-leukocyte). 24 This m o l e c u l e m a y therefore be o f significance in aggregation of the cells that comprise the LP infiltrate. T h e expression of endothelium-associated adhesion molecules by leukocytes in the LP infiltrate suggests that these molecules are also used for cell-cell c o m m u n i c a t i o n and aggregation. L-selectin, which is probably related to the early (initial) attachment of leukocytes to endothelium, is expressed b y most of the cells in the L P infiltrates. O f the t w o / C A M - 1 receptors, LFA-1 appears to be more significant than Mac-1 on the basis of the large n u m b e r s of cells expressing this molecule. V L A 4 (as well as LFA-1 and M a c - l ) can serve as an attachment molecule for the extracellular matrix (fibronectin). V L A 4 can also assist in aggregation of cells because of homotypic attachment. 39 In addition, the upregulation of adhesion molecules (ICAM-1, P E C A M , L-selectin, LFA-1, V L A 4 ) on intraepithelial dendritic cells (presumably L a n g e r h a n s ' cells) adds further evidence to the proposed antigen-processing role played by these cells. 23 These molecules m a y also be used in part to hold these cells in an intraepithelial position. A l t h o u g h vascular adhesion molecules appear to have a role in the pathogenesis o f LP, expression of these molecules c a n n o t be u n i q u e to LP. Basic microscopic appearances w o u l d indicate that recruitm e n t and retention of leukocytes is important in other i n f l a m m a t o r y - i m m u m e m u c o s a l diseases. Factors related to adhesion molecules that might partially explain the differences in the distribution and populations of i n f l a m m a t o r y cells seen in various oral conditions could i n c l u d e duration o f adhesion molecule expression, sequence of adhesion molecule expression, and intensity of the various adhesion molecules. The segment of the microvasculature (capillary loop, subepithelial plexus, s u b m u c o s a l network) expressing the adhesion molecules might also have an effect of cell selectivity. W h a t we have attempted to show by this p r e l i m i n a r y study is that in general m a n y vascular adhesion molecules are expressed and upregulated in lichen planus as compared with controls and therefore must be considered w h e n constructing a pathogenetic scheme for oral LP. Identification of the d o m i n a n t adhesion molecules and their cytokine mediators in L P m a y help in the d e v e l o p m e n t of new, rational, pathogenesis-directed treatment regimens. Chemotherapeutic blockage of adhesion molecules or receptor synthesis could limit
Regezi et al.
689
l y m p h o c y t e recruitment and subsequent tissue damage. However, because multiple receptors are involved in this process, multiple receptors m a y need to be targeted. Alternatively, control of the production or effectiveness of the cytokines that regulate the expression of adhesion molecules could prove efficacious in disease therapy. REFERENCES
1. Damle NK, Klussman K, Dietsch MT, Mohaghehpour N, Aruffo A. GMP-140 (P-selectin/CD62) binds to chronically stimulated but not resting CD4+ T lymphocytes and regulates their production of proinflammatory cytokines. Eur J Immunol 1992:22:1789-93. 2. Kishimoto TK, Warnock RA, Jutila MA, et al. Antibodies against human neutrophil LECAM-1 (LAM-1/Leu-8/ DREG-56 antigen) and endothelial cell ELAM-1 inhibit a common CD 18-independentadhesion pathway in vitro. Blood 1991 ;78:805-11. 3. Lasky LA. Selectins: interpreters of cell-specific carbohydrate information during inflammation. Science 1992;258: 964-9. 4. Picker LJ, Kishimoto TK, Smith CW, Warnock RA, Butcher EC. ELAM-1 is an adhesion molecule for skin-homing T cells. Nature 1991;349:796-8. 5. Shimizu Y, Shaw S, Graber N, et al. Activation-dependent binding of human memory T cells to adhesion molecule ELAM-1. Nature 1991;349:799-802. 6. Vestweber D; The selectins and their ligands. Curr Top Microbiol Immunol 1993;184:66-75. 7. Diamond MS, Stauton DE, Marlin SD, Springer TA. Binding of the integrin Mac-1 (CD1lb/CD18) to the third immunoglobulin-like domain of ICAM-1 (CD54) and its regulation by glycosylation. Cell 1991;65:961-71. 8. Sonnenberg A. Integrins and their ligands. Curr Top Microbiol Immunol 1993;184:7-35. 9. Akasu R, From L, Kahn HJ. Lymphocyte and macrophage subsets in active and inactive lesions of lichen planus. Am J Dermatopathol 1993;15:217-23. 10. Boisnic S, Frances C, Branchet M, Szpirglas H, Charpentier Y. Immunohistochemical study of oral lesions of lichen planus: diagnostic and pathophysiologic aspects. Oral Surg Oral Med Oral Pathol 1990;70:462-5. 11. Gilhar A, Pillar T, Winterstein G, Etzioni A. The pathogenesis of lichen planus. Br J Dermatol 1989;120:541-4. 12. Regezi JA, Daniels TE, Saeb F, Nickoloff BJ. Increased submucosal factor XIila+ dendrocytes in oral lichen planus. J Cut Pathol 1994;23:114-8. 13. Dustin ML, Springer TA. Role of lymphocyte adhesion receptors in transient interactions and cell locomotion. Annu Rev Immunol 1991;9:27-66. 14. Groves RW, Ross EL, Barker JNWN, MacDonald DM. Vascular cell adhesion molecule-1: expression in normal and diseased skin and regulation in vivo by interferon gamma. J Acad Dermatol 1993;29:67-72. 15. Hahne M, Jager U, Isenmann S, Hallmann R, Vestweber D. Five tumor necrosis factor-inducible cell adhesion mechanisms on the surface of mouse endothelioma cells mediate the binding of leukocytes. J Cell Biol 1993;121:655-64. 16. Marlor CW, Webb DL, Bombara MP, Greve JM, Blue ML. Expression of Vascularcell adhesion molecule-1 in fibroblastlike synoviocytes after stimulation with tumor necrosis factor. Am J Pathol 1992;140:1055-60. 17. Osborn L. Leukocyte adhesion to endothelium in inflammation. Cell 1990;62:3-6. 18. Rohde D, Schluter-Wigger W, Mielke V, von den Driesch P, yon Gaudeker B, Sterry W. Infiltration of both T cells and neutrophils in the skin is accompanied by the expression of
690
19. 20. 21. 22.
23.
24. 25. 26.
27. 28.
29. 30. 31.
Regezi et al.
endothelial leukocyte adhesion molecule-1 (ELAM-1): an immunohistochemical and ultrastructural study. J Invest Dermatol 1992;98:794-9. Shimizu Y, Newman W, Tanaka Y, Shaw S. Lymphocyte interactions with endothelial cells. Immunol Today 1992;13: 106-12. Springer TA. Adhesion receptors of the immune system. Nature 1990;346:425-33. Yednock TA~Rosen SD. Lymphocyte homing. Adv Immunol 1989;44:313-71. Konter U, Kellner I, Hoffmeister B, Sterry W. Induction and upregulation of adhesion receptors in oral and dermal lichen planus. J Oral Pathol Med 1990;19:459-63. Walton LJ, Thornhill MH, Farthing PM. VCAM-1 and ICAM-1 are expressed by Langerhans cells, macrophages, and endothelial cells in oral lichen planus. J Oral Pathol Med 1994;23:262- 8. DeLisser HM, Newman PJ, Albelda SM. Platelet endothelial cell adhesion molecule (CD31 ). Curt Top Microbiol Immunol 1993;184:37-45. Fina L, Molgaard HV, Robertson D, et al. Expression of the CD34 gene in vascular endothelial ceils. Blood 1990;75:241726. Norton J, Sloane JP, Delia D, Greaves MF. Reciprocal expression of CD34 and cell adhesion molecule ELAM-1 on vascular endothelium in acute cutaneous graft-versus-host disease. J Pathol 1993;170:173-7. Higgins JC, Eady RAJ. Human dermal microvasculature: I. its segmental differentiation. Br J Dermatol 1981;104:117-29. Ohta Y, Okada S, Toda I, Ike H. Scanning electron microscopic studies of the oral mucosa and its microvasculature: a review of the palatine mucosa and its microvasculature architecture in mammals. Scanning Micro 1992;6:463-74. Yu QX, Ran W, Pang KM, et al. The microvasculature of human oral mucosa using vascular corrosion casts and india ink injection I tongue papillae. 1992;6:255-62. Butcher EC. Cellular and molecular mechanisms that direct leukocyte traffic. Am J Pathol 1990;136:3-11. Fries JWU, Williams AJ, Atkins RC, Newman W, Lipscomb MF, Collins T. Expression of VCAM-1 and E-selectin in an
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 1996
32.
33. 34. 35.
36.
37.
38.
39.
in vivo model of endothelial activation. Am J Pathol 1993; 143:725-37. Groves RW, Ross E, Barker JNWN, Ross JS, Camp RDR, MacDonald DM. Effect of in vivo interleukin-1 on adhesion molecule expression in normal human skin. J Invest Dermatol 1992;98:384-7. Pober JS, Cotran RS. Cytokines and endothelial cell biology. Physiol Revs 1990;70:427-43. Rice GE, Munro JM, Corless C, Bevilacqua MP. Vascular and nonvascular adhesion in normal and inflamed human tissues. Am J Pathol 1991;138:385-93. Ruco PL, Pomponi D, Pigott R, Gearing AJH, Baiocchini A, Baroni CD. Expression and cell distribution of the intercellular adhesion molecule, vascular cell adhesion molecule, endothelial leukocyte adhesion molecule, and endothelial cell adhesion molecule (CD31) in reactive human lymph nodes and in Hodgkin's disease. Am J Pathol 1992;140:133744. Yamamoto T, Osaki T, Yoneda K, Ueta E. Cytokine production by keratinocytes and mononuclear infiltrates in oral lichen planus. J Oral Pathol Med 1994;23:309-15. Regezi JA, Nickoloff BJ, Headington JT. Oral submucosal dendrocytes: factor XIIIa+ and CD34+ dendritic cell populations in normal tissue and fibrovascular lesions. J Cutan Pathol 1992;19:398-406. Stoolman LM. Adhesion molecules involved in leukocyte recruitment and lymphocyte retention. Chest 1993;103:79S86S. Burkly LC, Jakubowski A, Newman BM, Rosa MD, ChiRosso G, Lobb RR. Signaling by vascular cell adhesion molecule- 1 (VCAM- 1) through V L A - 4 promotes CD3-dependent T cell proliferation. Eur J Immunol 1991;21:2871-5.
Reprint requests: Joseph A. Regezi, DDS, MS 513 Parnassus, S-512 University of California San Francisco CA, 94143-0424
Objective. Because recruitment and retention of lymphoid cells appear to be critical components of the pathogenesis of lichen planus, we have compared the expression and distribution of a panel of vascular adhesion molecules (ELAM-1, P-selectin, ICAM-1, VCAM-1, PECAM-1, CD34) and leukocyte adhesion molecule ligands (LFA-1, Mac-l, VLA4, L-selectin) in biopsies of this disease. Study design. Frozen sections of 12 clinically and histologically confirmed cases of lichen planus and 9 normal control tissues were evaluated immunohistochemically with a standard 1-day avidin-biotin peroxidase technique. Staining intensity of vascular endothelium was evaluated semiquantitatively. Three microvascular zones or compartments were defined and evaluated separately. Results. Generally, different staining patterns were observed in association with the various endothelium-associated adhesion molecules. In normal controls, PECAM was intensely expressed and VCAM-1 was weakly expressed. Intermediate staining was associated with ELAM-1, P-selectin, ICAM-1, and CD34. Staining within the three microvascular compartments frequently showed variations in intensity. In lichen planus, increased staining for ELAM-1, P-selectin, ICAM-1, and VCAM-1 was evident in one or more of the microvascular compartments. In the subepithelial vascular compartment where the infiltrate was the most dense, VCAM-1 appeared to show the greatest positive change. Almost all cells in the lichen planus infiltrates stained positive for ICAM-1, L-selectin, LFA-1, and VLA4, and large numbers of cells also exhibited VCAM-1, PECAM-1, and Mac-1 immunoreactivity. Conclusions. It appears that upregulation of ELAM-1, ICAM-1, and VCAM-1 (especially by endothelial cells in the subepithelial vascular plexus) could play a r01e in the pathogenesis of lichen planus. The expression of leukocyte receptors L-selectin, LFA-1, and VLA4 by most of the cells in the lichen planus infiltrate suggest that these molecules may be responsible for recruitment as well as retention in the active lichen planus lesion. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;81:682-90)
Recruitment of leukocytes to sites of inflammation or immunologic challenge is associated with a cascade of leukocyte-endothelial cell adhesion events that involve molecules from several families (selectins, integrins, immunoglobulin superfamily). The selectins, L-selectin, E-selectin (endothelial leukocyte adhesion molecule, ELAM-1), and P-selectin, whose ligands are cell surface carbohydrates, are believed to be involved i n cell-cell adhesion early in the process of lymphocyte homing. 1-6 Leukocyte-associated molecules from the integrin family are involved in leukocyte adhesion to vascular endothelium. 7, 8 The [3-2 integrins, LFA-1 and Mac-l, are ligands for immunoglobulin supergene family molecule, ICAM-1 (intercellular adhesion molecule). The [3-1 integrin, VLA-4, is a ligand for immunoglobulin supergene aDepartmentof Stomatology, School of Dentistry and Department of Pathology, School of Medicine. bDepartment of Stomatology, School of Dentistry. CDepartment of Pathology, School of Medicine. Received for publication Dec. 28, 1994; returned for revision June 13, 1995; accepted for publication Sept. 14, 1995. Copyright 9 1996 by Mosby-Year Book, Inc. 1079-2104/96/$5.00 + 0 7/14/69408
682
molecule, VCAM-1 (vascular adhesion molecule). Another molecule from the same family, PECAM-1 (platelet endothelial cell adhesion molecule) with an undetermined ligand, is believed to be involved in leukocyte recruitment. Blood vessel-associated CD34, which is not structurally related to any of the aforementioned three molecular families, is also thought to be associated with leukocyte-endothelial cell adhesion. Many of these adhesion molecules are believed to be involved in the retention of these leukocytes in the disease focus. Lichen planus (LP) is characterized microscopically by an intense T-cell infiltrate with large numbers of macrophages and XIIIa+ dendrocytes, located at the interface of epithelium and connective tissue. 9-12 From what is known of leukocyte kinetics in tissue, attraction of these cells to an active disease site would require cytokine-mediated upregulation of adhesion molecules by endothelial cells and expression of receptor molecules by lymphocytes and macrophages: 13-21 Altered endothelial cell expression of ELAM-1, ICAM-1, 22 and VCAM-123 has been reported in oral LP, which indicates a role in disease pathogenesis.
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6
Regezi et al.
683
Table I. Antibodies used to identify vascular adhesion molecules and leukocyte ligands Antigen
CD#
ELAM-1 P-selectin ICAM-1
CD62E CD62 CD54
VCAM-1
CD106
PECAM-l
CD31
CD34 L-selectin LFA-1 Mac-1 VLA4
CD34 CD62L CD1la/18 CD1 lb/18 CD49d
Family
Selectin Selectin Immunoglobulin superfamily Immunoglobulin superfamily Immunoglobulin superfamily -Selectin Integrin Integrin Integrin
Antibody clone,type
Source
Dilution
BBIG-E-6,IgG1 ACI-2, IgG1 BBIG-I1,IgG1
R & D Systems,Minneapolis, Minn. Becton Dickinson, San Jose, Calif. R & D Systems
1:1000 1:50 1:2000
BBIG-VI,IgG1
R & D Systems
1:500
--, IgG1
R & D Systems
1:4000
Becton Dickinson Becton Dickinson Dako, Carpinteria, Calif. R & D Systems Upstate Biotechnology,Lake Placid, N.Y.
1:20 1:100 1:100 1:20 1:200
HPCA-1, IgG1 SK-11, IgG2A MHM23, IgG1 44, IgGl B-5G10, IgGl
Other vascular adhesion molecules, such as P-selectin, PECAM-1, and CD34, which may contribute to recruitment of lymphocytes, 1, 19, 24-26 have not been evaluated in LP. The purpose of this investigation was to compare the expression and distribution of a panel of vascular adhesion molecules (ELAM-1, P-selectin, ICAM-1, VCAM-1, PECAM-1, CD34) of potential importance in LP and to compare results with expression of the same molecules in normal tissue. In addition, the leukocyte adhesion molecule ligands (LFA-1, Mac-l, VLA4, L-selectin) on the cellular infiltrate in LP were also evaluated. MATERIAL AND METHODS Oral biopsy specimens of LP (10 buccal mucosa, 2 gingiva) were divided before processing; half of each specimen was immediately frozen in liquid nitrogen for frozen sections, and half was placed in formalin for paraffin sections. The diagnoses of the 12 clinically acceptable cases of oral LP were confirmed with hematoxylin-eosin sections. Microscopic criteria required for inclusion were hyperkeratosis, basal layer vacuolization, individual basal cell necrosis, and a lymphophagocytic infiltrate limited to the interface of the epithelium and connective tissue. Patients (8 women, 4 men) had a mean age of 50 years (range, 32 to 67 years). Seven patients had oral symptoms described as buming or discomfort; two of this group had associated ulcerations. None of the patients were under active treatment for LP, and none were taking drugs that are known to cause lichenoid reactions. Four patients had LP limited to the buccal mucosae only, and eight had additional sites involved. Normal control tissues consisted of four buccal mucosa specimens from unaffected sites in four of the patients
with LP and five gingival specimens from healthy adults without LP. Immunohistochemical staining was done to evaluate expression of endothelial cell-associated adhesion molecules (ELAM-1, P-selectin, ICAM-1, VCAM-1, PECAM-1, CD34) and leukocyte receptor molecules (L-selectin, LFA-1, M a c - l , VLA4) (Table I). Frozen sections of LP and control sections of normal mucosa were incubated with monoclonal antibodies; paraffinembedded sections were also used to evaluate CD34 expression. A standard 1-day avidin-biotin peroxidase technique (Vectastain, Elite, Vector Laboratory, Buflingame, Calif.) was used. Sections were developed in aminoethylcarbazole and counterstained with M a y e r ' s hematoxylin. Negative controls consisted of tissue sections on which primary antibody was replaced with mouse serum. Staining intensity of vascular endothelium was evaluated semiquantitatively with a staining scale of slight (+), moderate (++), and intense (+++). The various microvascular compartments 27-29 (the capillary loops in the connective tissue papillae, the subepithelial vascular plexus, and the submucosal vascular network) were evaluated separately. Although division of the microvasculature into three compartments was somewhat artificial, it did prove to be practical and useful because endothelial staining was often different in these zones. For leukocyte staining, percentages of positively stained cells were estimated from three representative high power fields.
RESULTS Vascular adhesion molecules in normal mucosa In general the control tissues from buccal mucosa and gingiva gave similar results, although the gingi-
684
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 1996
Regezi et al.
II. S u m m a r y o f general staining results for adhesion m o l e c u l e s in L P (n = 12) and controls (n = 9). G r a d i n g scale indicates staining intensity, 0 = negative, + = slight; ++ = m o d e r a t e , +§ = intense. A l l cases stained at intensity shown unless shown in parentheses (n).
Table
Vascular endothelium
Antigen
Controls
Infiltrate
Lichen planus
Controls
Lichen planus (%)
ELAM-1
A 0 (1), + (8)
A ++
--
--
P-selectin
B + (5), ++ (4) C ++ A 0 (3), + (6)
B + (1), ++ (11) C ++ (5), +++ (7) A +
--
--
ICAM-I*
B + (1), ++ (8) C ++ A ++
B ++ C ++ A +++ B +++
B ++ VCAM-I
PECAM-1
CD34
C ++
C +++
A + B 0 CO A +++ B +++ C +++ A ++
A + (6), ++ (6) B ++ C+ A +++ B +++ C +++ A §
B ++ C ++
B + (6), ++ (6) C ++ --
L-selectin
--
LFA-1
--
--
Mac-1
--
--
VLA4
--
--
++ few cells (9)
++ 90-95I
+ few d e n d r o c y t e s (2)
++ 25-75
++ f e w d e n d r o c y t e s (8)
++ 2 5 - 5 0 t
--
+ few round cells (7) +++ many round cells (9) + few dendrocytes (5) + few dendrocytes (8)t
--
++ 90t +++ 95-100t + 1-50 ++ 90-95t
A, capillary loops in connective tissue papillae. B, vascular plexus in subepithelial connective tissue. C, vascular network in submucosa. *Some keratinocytes positive with antibodies to this antigen. tPositive staining of intraepithelial dendritic cells also noted with antibodies to this antigen.
val s p e c i m e n s s h o w e d slightly increased staining intensity associated with E L A M - 1 and V C A M - 1 . Different staining patterns were o b s e r v e d in association with the various e n d o t h e l i u m - a s s o c i a t e d adhesion m o l e c u l e s (Table II). P E C A M was the m o s t intensely e x p r e s s e d a d h e s i o n molecule; it stained all vessels in the three m u c o s a l microvascular c o m p a r t ments (Fig. 1). V C A M - 1 was the w e a k e s t staining m o l e c u l e tested and was l i m i t e d essentially to endothelial cells in the c a p i l l a r y loops o f the connective tissue papillae. In contrast, E L A M - 1 and P-selectin w e r e either w e a k l y e x p r e s s e d or not e x p r e s s e d in c a p i l l a r y loops but w e r e e v i d e n t in l o w e r level vessels. Staining intensity for I C A M - I and C D 3 4 was intermediate b e t w e e n these t w o extremes. A l t h o u g h C D 3 4 was e v i d e n t in frozen sections, it was m o r e intense and had better contrast in p a r a f f i n - e m b e d d e d sections. C D 3 4 staining was t y p i c a l l y f o u n d on the luminal surface o f e n d o t h e l i a l cells.
Leukocyte adhesion molecules in normal mucosa In submucosa, small numbers o f r o u n d cells with either l y m p h o c y t e or m a c r o p h a g e m o r p h o l o g y stained p o s i t i v e for I C A M - 1 and L-selectin ( T a b l e II). L F A - 1 was r e s p o n s i b l e for staining larger n u m b e r s o f simi l a r l y shaped cells. C o n n e c t i v e tissue dendritic cells in the upper s u b m u c o s a o c c a s i o n a l l y stained p o s i t i v e for V C A M - 1 , P E C A M - 1 , Mac-1, and V L A 4 . In the d e e p submucosa, a s e e m i n g l y different p o p u l a t i o n o f dendritic cells w e r e positive for CD34. Rarely, intraepithelial dendritic cells stained w e a k l y positive for V L A 4 .
Vascular adhesion molecules in lichen planus P E C A M - I a p p e a r e d to be m a x i m a l l y e x p r e s s e d in both L P and controls (Fig. 2). I n c r e a s e d staining for E L A M - 1 , P-selectin, I C A M - 1 , and V C A M - 1 was e v i d e n t in one or m o r e o f the m i c r o v a s c u l a r compartm e n t s (Table II) (Figs. 3-6). O c c a s i o n a l l y the subep-
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6
Regezi et al.
685
Epitherlum
Capillary loops
inCTpapilaeI
Subepithelivascul al aplrexus.<~ 0 '=::=> 0
r
o
Submucosalvascularnetwork.<~ 0 ~ ~
0
0 ~ 0
~
0<:::=:,0 ~) 0 (~ 0
0 Fig. 1. Typical immunohistochemical staining pattern for PECAM-1 in control mucosa illustrates the three microvascular "compartments" that were evaluated.
Fig. 2. Immunohistochemical stains for PECAM-I in LP (A) and control specimens (B). Note that both endothelium and inflammatory cells are positive. (Hematoxylin counterstain; original magnification xl00.) ithelial vascular plexus (within the lymphoid infiltrate) stained less intensely for ELAM-1, P-selectin, and CD34 than the other two vascular compartments. As with normal control sections, CD34 staining was consistently of better quality in formalin-fixed, paraffin-embedded sections. Similar or slightly reduced staining intensity for this molecule was evident on subepithelial vessels within the infiltrate.
Leukocyte adhesion molecules in lichen planus Almost all the cells in all the LP infiltrates stained positive for ICAM-1, L-selectin, LFA-1, and VLA4 (Fig. 7). Large numbers of cells also exhibited VCAM-1, PECAM-1, and Mac-1 immunoreactivity (Table II). Intraepithelial dendritic cells (presumably
Langerhans' cells) exhibited upregulation o f l C A M - 1, PECAM, L-selectin, LFA-1, and VLA4.
Discussion The expression of a series of vascular adhesion molecules is involved in the movement of leukocytes from the vascular system to extracellular spaces. Under normal conditions, subsets of leukocytes that bear the receptors for these molecules, infiltrate specific sites, such as mucosa, where they perform a surveillance function. In inflammatory/immune conditions, upregulation of vascular adhesion molecules is responsible for recruitment and retention of the infiltrates that typify these diseases. Site and disease specificity is believed to be related to endothelial ex-
686
Regezi et al.
ORAL SURGERY ORAL MEDICINEORAL PATHOLOGY June 1996
Fig. 3. Immunohistochemical stain for ELAM-1 shows positive reaction on most submucosal vessels. (Hematoxylin counterstain; original magnification xl00.)
Fig. 4. Stain for P-selectin shows most intense reaction on endothelial cells subjacent to the lymphophagocytic infiltrate. Pale zones between infiltrate (upper half) represent epithelium. (Hematoxylin counterstain; original magnification xlO0.)
pression of a combination of vascular adhesion molecules, which themselves may be regulated by disease-specific cytokines, such as TNFo~, IL-1, and interferon-'y. 16'3~ The site, oral mucosa, and the
disease, LP, would therefore be expected to be characterized by the expression of a specific series of vascular adhesion molecules (and cytokines36), Whether there are vascular adhesion molecules that
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6
Regezi et al.
687
Fig. 5. Immunohistochemical stain for ICAM-1 in LP (A) and control (B). Note the vessels, infiltrate, and parabasal keratinocytes are positive in LP. (Hematoxylin counterstain; original magnification xl00.) are unique to oral mucosa lymphocyte homing has not been determined.
different population of dendritic cells whose origin and function are undetermined.
Adhesion molecules in normal mucosa
Adhesion molecules in lichen planus
In normal oral mucosa, expression of vascular adhesion molecules varies from one microvascular compartment to another. Normally, capillary loop endothelium expresses ICAM- l and VCAM- 1 weakly and PECAM-1 and CD34 more intensely. The epithelium lining the subepithelial vascular plexus, which would include capillaries, arterioles, and venules, expresses all molecules except VCAM-1. Staining of the deeper submucosal vessels also shows no expression of VCAM-1. These regional staining differences of the microvasculature of oral mucosa suggest that there is independent regulation of these molecules, and that normal leukocyte trafficking may be associated with segmental expression of various specific adhesion molecules. The staining results of normal mucosa suggest that cell trafficking is strongly associated with lymphocyte expression of LFA-1 and less so with L-selecfin. Expression by round cells and dendritic cells in connective tissue of several of the adhesion molecules tested is likely related to cell-cell communication as well as site retention. The upper level connective tissue dendritic cells, by virtue of position and morphology, likely represent part of the macrophage-related XIIIa dendrocyte p o p u l a t i o n s The deeper CD34-positive dendritic cells appear to represent a
The recruitment of the characteristic lymphophagocytic infiltrate of LP must be related to endothelial expression of a characteristic type or series of adhesion molecules and the reciprocal expression of specific receptors by circulating lymphocytes and macrophages. A comparison of the results of all vessel-associated molecules show that upregulation of ELAM-1, ICAM-1, VCAM-1, and P-selecfin is important in the maintenance or persistence of LP lesions.14, 22, 23 Endothelial expression of ELAM (Eselecfin) and P-selecfin, adhesion molecules that are operative in early stages of leukocyte-endothelial attachment, may be expressed in LP because of persistent, continuous leukocyte recruitment. Because VCAM-1 is not expressed by neutrophils, this molecule may help select for lymphocytes and macrophages. 38 The upregulation of VCAM-1 was of particular note because the changes were most dramatic in the vessels in which the infiltrate was the most dense. In contrast, the slightly decreased staining for ELAM-1 and P-selectin of vessels in the same location suggests these molecules may be less important than VCAM- 1 for cell recruitment in this microvascular zone. It has been suggested that negative or decreased modulation of CD34 is associated with leukocyte adhesion to endothelium. 25 This could not be
688
Regezi et al.
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 1996
Fig. 6. Immunohistochemical stain for VCAM-1 shows positive reaction on both vessels (arrows) and round ceils. (Hematoxylin counterstain; original magnification xl00.)
Fig. 7. Immunohistochemical stains for leukocyte-associated adhesion molecules in LP shows positive reaction on most cells: A, L-selectin; B, LFA-I: C, VLA-4. (Hematoxylin counterstain; original magnification xlO0.)
confirmed in this study. It is also interesting to note that downregulation of CD34 has been associated with cytokine release in vitro and with graft-versus-host disease, a condition that simulates LP microscopically. 26
PECAM-1, which may be involved in the leukocyte-endothelial adhesion cascade, appears to be constitutively expressed on endothelium and macrophages. The persistent high level of P E C A M expres-
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 81, Number 6 sion in control and disease tissue suggests that in vivo activation is required before this molecule can be of functional significance.24 In addition to its role in heterotypic interaction (leukocyte-endothelial cell), it is believed to function in a homotypic fashion (leukocyte-leukocyte). 24 This m o l e c u l e m a y therefore be o f significance in aggregation of the cells that comprise the LP infiltrate. T h e expression of endothelium-associated adhesion molecules by leukocytes in the LP infiltrate suggests that these molecules are also used for cell-cell c o m m u n i c a t i o n and aggregation. L-selectin, which is probably related to the early (initial) attachment of leukocytes to endothelium, is expressed b y most of the cells in the L P infiltrates. O f the t w o / C A M - 1 receptors, LFA-1 appears to be more significant than Mac-1 on the basis of the large n u m b e r s of cells expressing this molecule. V L A 4 (as well as LFA-1 and M a c - l ) can serve as an attachment molecule for the extracellular matrix (fibronectin). V L A 4 can also assist in aggregation of cells because of homotypic attachment. 39 In addition, the upregulation of adhesion molecules (ICAM-1, P E C A M , L-selectin, LFA-1, V L A 4 ) on intraepithelial dendritic cells (presumably L a n g e r h a n s ' cells) adds further evidence to the proposed antigen-processing role played by these cells. 23 These molecules m a y also be used in part to hold these cells in an intraepithelial position. A l t h o u g h vascular adhesion molecules appear to have a role in the pathogenesis o f LP, expression of these molecules c a n n o t be u n i q u e to LP. Basic microscopic appearances w o u l d indicate that recruitm e n t and retention of leukocytes is important in other i n f l a m m a t o r y - i m m u m e m u c o s a l diseases. Factors related to adhesion molecules that might partially explain the differences in the distribution and populations of i n f l a m m a t o r y cells seen in various oral conditions could i n c l u d e duration o f adhesion molecule expression, sequence of adhesion molecule expression, and intensity of the various adhesion molecules. The segment of the microvasculature (capillary loop, subepithelial plexus, s u b m u c o s a l network) expressing the adhesion molecules might also have an effect of cell selectivity. W h a t we have attempted to show by this p r e l i m i n a r y study is that in general m a n y vascular adhesion molecules are expressed and upregulated in lichen planus as compared with controls and therefore must be considered w h e n constructing a pathogenetic scheme for oral LP. Identification of the d o m i n a n t adhesion molecules and their cytokine mediators in L P m a y help in the d e v e l o p m e n t of new, rational, pathogenesis-directed treatment regimens. Chemotherapeutic blockage of adhesion molecules or receptor synthesis could limit
Regezi et al.
689
l y m p h o c y t e recruitment and subsequent tissue damage. However, because multiple receptors are involved in this process, multiple receptors m a y need to be targeted. Alternatively, control of the production or effectiveness of the cytokines that regulate the expression of adhesion molecules could prove efficacious in disease therapy. REFERENCES
1. Damle NK, Klussman K, Dietsch MT, Mohaghehpour N, Aruffo A. GMP-140 (P-selectin/CD62) binds to chronically stimulated but not resting CD4+ T lymphocytes and regulates their production of proinflammatory cytokines. Eur J Immunol 1992:22:1789-93. 2. Kishimoto TK, Warnock RA, Jutila MA, et al. Antibodies against human neutrophil LECAM-1 (LAM-1/Leu-8/ DREG-56 antigen) and endothelial cell ELAM-1 inhibit a common CD 18-independentadhesion pathway in vitro. Blood 1991 ;78:805-11. 3. Lasky LA. Selectins: interpreters of cell-specific carbohydrate information during inflammation. Science 1992;258: 964-9. 4. Picker LJ, Kishimoto TK, Smith CW, Warnock RA, Butcher EC. ELAM-1 is an adhesion molecule for skin-homing T cells. Nature 1991;349:796-8. 5. Shimizu Y, Shaw S, Graber N, et al. Activation-dependent binding of human memory T cells to adhesion molecule ELAM-1. Nature 1991;349:799-802. 6. Vestweber D; The selectins and their ligands. Curr Top Microbiol Immunol 1993;184:66-75. 7. Diamond MS, Stauton DE, Marlin SD, Springer TA. Binding of the integrin Mac-1 (CD1lb/CD18) to the third immunoglobulin-like domain of ICAM-1 (CD54) and its regulation by glycosylation. Cell 1991;65:961-71. 8. Sonnenberg A. Integrins and their ligands. Curr Top Microbiol Immunol 1993;184:7-35. 9. Akasu R, From L, Kahn HJ. Lymphocyte and macrophage subsets in active and inactive lesions of lichen planus. Am J Dermatopathol 1993;15:217-23. 10. Boisnic S, Frances C, Branchet M, Szpirglas H, Charpentier Y. Immunohistochemical study of oral lesions of lichen planus: diagnostic and pathophysiologic aspects. Oral Surg Oral Med Oral Pathol 1990;70:462-5. 11. Gilhar A, Pillar T, Winterstein G, Etzioni A. The pathogenesis of lichen planus. Br J Dermatol 1989;120:541-4. 12. Regezi JA, Daniels TE, Saeb F, Nickoloff BJ. Increased submucosal factor XIila+ dendrocytes in oral lichen planus. J Cut Pathol 1994;23:114-8. 13. Dustin ML, Springer TA. Role of lymphocyte adhesion receptors in transient interactions and cell locomotion. Annu Rev Immunol 1991;9:27-66. 14. Groves RW, Ross EL, Barker JNWN, MacDonald DM. Vascular cell adhesion molecule-1: expression in normal and diseased skin and regulation in vivo by interferon gamma. J Acad Dermatol 1993;29:67-72. 15. Hahne M, Jager U, Isenmann S, Hallmann R, Vestweber D. Five tumor necrosis factor-inducible cell adhesion mechanisms on the surface of mouse endothelioma cells mediate the binding of leukocytes. J Cell Biol 1993;121:655-64. 16. Marlor CW, Webb DL, Bombara MP, Greve JM, Blue ML. Expression of Vascularcell adhesion molecule-1 in fibroblastlike synoviocytes after stimulation with tumor necrosis factor. Am J Pathol 1992;140:1055-60. 17. Osborn L. Leukocyte adhesion to endothelium in inflammation. Cell 1990;62:3-6. 18. Rohde D, Schluter-Wigger W, Mielke V, von den Driesch P, yon Gaudeker B, Sterry W. Infiltration of both T cells and neutrophils in the skin is accompanied by the expression of
690
19. 20. 21. 22.
23.
24. 25. 26.
27. 28.
29. 30. 31.
Regezi et al.
endothelial leukocyte adhesion molecule-1 (ELAM-1): an immunohistochemical and ultrastructural study. J Invest Dermatol 1992;98:794-9. Shimizu Y, Newman W, Tanaka Y, Shaw S. Lymphocyte interactions with endothelial cells. Immunol Today 1992;13: 106-12. Springer TA. Adhesion receptors of the immune system. Nature 1990;346:425-33. Yednock TA~Rosen SD. Lymphocyte homing. Adv Immunol 1989;44:313-71. Konter U, Kellner I, Hoffmeister B, Sterry W. Induction and upregulation of adhesion receptors in oral and dermal lichen planus. J Oral Pathol Med 1990;19:459-63. Walton LJ, Thornhill MH, Farthing PM. VCAM-1 and ICAM-1 are expressed by Langerhans cells, macrophages, and endothelial cells in oral lichen planus. J Oral Pathol Med 1994;23:262- 8. DeLisser HM, Newman PJ, Albelda SM. Platelet endothelial cell adhesion molecule (CD31 ). Curt Top Microbiol Immunol 1993;184:37-45. Fina L, Molgaard HV, Robertson D, et al. Expression of the CD34 gene in vascular endothelial ceils. Blood 1990;75:241726. Norton J, Sloane JP, Delia D, Greaves MF. Reciprocal expression of CD34 and cell adhesion molecule ELAM-1 on vascular endothelium in acute cutaneous graft-versus-host disease. J Pathol 1993;170:173-7. Higgins JC, Eady RAJ. Human dermal microvasculature: I. its segmental differentiation. Br J Dermatol 1981;104:117-29. Ohta Y, Okada S, Toda I, Ike H. Scanning electron microscopic studies of the oral mucosa and its microvasculature: a review of the palatine mucosa and its microvasculature architecture in mammals. Scanning Micro 1992;6:463-74. Yu QX, Ran W, Pang KM, et al. The microvasculature of human oral mucosa using vascular corrosion casts and india ink injection I tongue papillae. 1992;6:255-62. Butcher EC. Cellular and molecular mechanisms that direct leukocyte traffic. Am J Pathol 1990;136:3-11. Fries JWU, Williams AJ, Atkins RC, Newman W, Lipscomb MF, Collins T. Expression of VCAM-1 and E-selectin in an
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 1996
32.
33. 34. 35.
36.
37.
38.
39.
in vivo model of endothelial activation. Am J Pathol 1993; 143:725-37. Groves RW, Ross E, Barker JNWN, Ross JS, Camp RDR, MacDonald DM. Effect of in vivo interleukin-1 on adhesion molecule expression in normal human skin. J Invest Dermatol 1992;98:384-7. Pober JS, Cotran RS. Cytokines and endothelial cell biology. Physiol Revs 1990;70:427-43. Rice GE, Munro JM, Corless C, Bevilacqua MP. Vascular and nonvascular adhesion in normal and inflamed human tissues. Am J Pathol 1991;138:385-93. Ruco PL, Pomponi D, Pigott R, Gearing AJH, Baiocchini A, Baroni CD. Expression and cell distribution of the intercellular adhesion molecule, vascular cell adhesion molecule, endothelial leukocyte adhesion molecule, and endothelial cell adhesion molecule (CD31) in reactive human lymph nodes and in Hodgkin's disease. Am J Pathol 1992;140:133744. Yamamoto T, Osaki T, Yoneda K, Ueta E. Cytokine production by keratinocytes and mononuclear infiltrates in oral lichen planus. J Oral Pathol Med 1994;23:309-15. Regezi JA, Nickoloff BJ, Headington JT. Oral submucosal dendrocytes: factor XIIIa+ and CD34+ dendritic cell populations in normal tissue and fibrovascular lesions. J Cutan Pathol 1992;19:398-406. Stoolman LM. Adhesion molecules involved in leukocyte recruitment and lymphocyte retention. Chest 1993;103:79S86S. Burkly LC, Jakubowski A, Newman BM, Rosa MD, ChiRosso G, Lobb RR. Signaling by vascular cell adhesion molecule- 1 (VCAM- 1) through V L A - 4 promotes CD3-dependent T cell proliferation. Eur J Immunol 1991;21:2871-5.
Reprint requests: Joseph A. Regezi, DDS, MS 513 Parnassus, S-512 University of California San Francisco CA, 94143-0424