- Email: [email protected]
Interleukin-16 in patients with alopecia areata
Journal of Dermatological Science (2005) 37, 55—57
www.intl.elsevierhealth.com/journals/jods
LETTER TO THE EDITOR Interleukin-16 in patients with alopecia areata The details of the pathogenesis of alopecia areata (AA) still remain unclear. However, several studies have indicated that AA is an organ-specific autoimmune disease and that T cells (especially CD8+ T cells) may play an important role in its development, as well as certain cytokines (such as interleukin (IL)-1 beta, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha) [1,2]. For example, AA is reinduced by the injection of hair folliclespecific CD8+ T cells into scalp biopsy tissue specimens from AA patients grafted into severe combined immunodeficiency (SCID) mice [3]. IL-16 is a soluble ligand of CD4 that can induce the activation and resultant energy (low responsiveness to antigenic stimuli) of CD4+ cells, as well as promoting chemotaxis by CD4+ cells [4,5] The first cellular source of active IL-16 to be identified was activated CD8+ T cells and the IL-16 level in sera and/or foci is known to be elevated with disease activity in certain autoimmune diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), and in allergic diseases including atopic dermatitis and asthma [5—7]. Based on these findings, we investigated the circulating level of IL16 in AA patients to assess its possible pathogenic role in the development of AA. Ninety patients (30 males and 60 females with an average age of 33 years) with AA were involved in this study and the patients were classified into the following two groups according to the previous study with slight modifications [8]. Type 1 (inactive AA with multiple lesions): more than four circular bald patches are observed on the scalp, the hair pull test is negative, and exclamation point hair is absent. Patients with chronic alopecia universalis (AU; patients who had not shown any new hair growth for 18 months) were also classified into this type. Type 2 (active AA with multiple lesions): more than four bald circular patches and a positive hair pull test. Patients with alopecia totalis (AT) who had
complete baldness localized to the scalp were also classified into this type. The serum level of IL-16 was measured by a sandwich enzyme-linked immunosorbent assay (ELISA) (CytoscreenTM hIL-16 kit, Biosource International, Camarillo, CA, USA) [5]. Flow cytometry analysis was performed using a FACStar plus (Becton Dickinson, San Jose, CA, USA) with PE-labelled anti-CD4 and anti-CD8 monoclonal antibodies (Becton Dickinson), and a FITClabelled anti-HLA-DR antibody (Becton Dickinson) was also used for double staining in some experiments. Statistical analysis (Student’s t-test and Peason’s correlation coefficient analysis) was performed with commercially available statistical software (SPSS, Chicago, IL, USA), and p < 0.05 was considered to indicate significance. The IL-16 level found in type 2 (active) patients was significantly higher than in normal individuals or type 1 (inactive) patients (p < 0.05), while there was no significant difference of IL-16 between normal controls and type 1 patients (Fig. 1). The main source of IL-16 is thought to be activated CD8+ T cells, so we examined the relationship between the IL-16 level and HLA-DR expression (which generally occurs in the active phase of the cell cycle; G1A) by T cells in each patient group. A significant correlation between HLA-DR expression by CD8+ T cells and the IL-16 level was observed in type 2 patients (p < 0.05, r = 0.353), but was not recognized in type 1 patients (Table 1). Regarding CD4+ T cells, there was no significant correlation between HLA-DR expression and the serum IL-16 level in either type 1 or 2 patients (data not shown). Our data indicated that there is an increase of the circulating IL-16 level in AA patients along with disease activity and the IL-16 level is related to the presence of HLA-DR+CD8+ T cells. Supporting this concept, ectopic expression of HLA-DR (a class II major histocompatibility antigen) is observed in perifollicular lymphocytes invading AA lesions [9], as well as an increase of class I antigens [10]. Autoantigens are generally presented with class I major histocompatibility antigens and recognized by CD8+ T cells, leading to the activation (implied by HLA-DR
0923-1811/$30.00 # 2004 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jdermsci.2004.09.006
56
Letter to the Editor
Table 1 Relationship between IL-16 and HLA-DR expression by CD8+ T cells in AA patients p value*
Mean value (range) Inactive (n = 16) Active (n = 32) *
IL-16 (pg/dl)
HLA-DR on CD8+ T (%)
73.01 (48.34 97.68) 171.99 (144.92 199.06)
6.06 (1.9 5.49 (1.1
12.4) 13.5)
>0.05 <0.05
IL-16 concentration vs. HLA-DR expression.
expression) of CD8+ T cells [5]. Thus, the pathogenic role of CD8+ Tcells in AA patients may partly involve production of cytokines (including IL-16) by these activated cells after stimulation with several types of auto-antigens. A similar relationship between IL-16 and activated CD8+ T cells has been suggested to have a role in the etiology of SLE, which is a representative autoimmune disease [5]. In RA, however, adoptive transfer of synovial tissue CD8+ Tcells and IL-16 derived from these cells actually reduces disease activity in the synovium of model mice [6]. This may be explained by the concept that IL-16mediated CD4+ T cell activation and consequent
energy cause a decrease of the CD4+ T cell response to arthritogenic antigens in the synovium [6]. Thus, IL-16 appears to play opposing roles (proinflammatory or antiinflammatory effect) in different disorders. The findings obtained from transfer of CD8+ T cells into AA scalp-SCID mice, as described above [3], seem to indicate that IL-16 acts as a proinflammatory cytokine in the development of AA. However, we cannot also completely neglect the possibility of an antiinflammatory role of IL-16 in AA, because IL-16 can inhibit the production of AApromoting cytokines such as IL-1, IFN-gamma, and TNF-alpha [6]. IL-16 seems to be a useful indicator of the activity of AA and that it may play an important role in the development of this disease. Further investigations are required to clarify the pathogenic role and clinical significance of IL-16, and these findings may provide important clues to assist in the development of new therapeutic strategies for patients with AA.
Acknowledgement This work was supported by the grants from The Institute for Environmental and Gender-specific Medicine, Juntendo University School of Medicine.
References
Fig. 1 Serum levels of IL-16 in healthy controls and AA patients. Bars indicate mean values in each group. Absolute numbers of mean value standard deviation are as follows: control, 74.31 51.86 pg/dl; inactive AA, 72.56 75.13 pg/dl; active AA, 153.62 137.19 pg/dl.
[1] Paus R, Slominski A, Czarnetzki BM. Is alopecia areata an autoimmune-response against melanogenesis-related proteins, exposed by abnormal MHC class I expression in the anagen hair bulb? Yale J Biol Med 1993;66(6):541—54. [2] Hoffmann R, Wenzel E, Huth A, et al. Cytokine mRNA levels in Alopecia areata before and after treatment with the contact allergen diphenylcyclopropenone. J Invest Dermatol 1994;103:530—3. [3] Gilhar A, Shalaginov R, Assy B, Serafimovich S, Kalish RS. Alopecia areata is a T-lymphocyte mediated autoimmune disease: lesional human T-lymphocytes transfer alopecia areata to human skin grafts on SCID mice. J Investig Dermatol Symp Proc 1999;4:207—10. [4] Center DM, Kornfeld H, Cruikshank WW. Interleukin 16 and its function as a CD4 ligand. Immunol Today 1996;17:476— 81.
Letter to the Editor
57
[5] Sekigawa I, Matsushita M, Lee S, et al. A possible pathogenic role of CD8+ T cells and their derived cytokine, IL-16, in SLE. Autoimmunity 2001;33:37—44. [6] Klimiuk PA, Goronzy JJ, Weyand CM. IL-16 as an anti-inflammatory cytokines in rheumatoid synovitis. J Immunol 1999;162:4293—9. [7] Masuda K, Katoh N, Okuda F, Kishimoto S. Increased levels of serum interleukin-16 in adult type atopic dermatitis. Acta Derm Venereol 2003;83:249—53. [8] Imai R, Miura J, Takamori K, Ogawa H. Increased HLA-DR+ T-lymphocyte population in peripheral blood of alopecia areata. Clin Exp Dermatol 1991;16:176—81. [9] Khoury EL, Price VH, Greenspan JS. HLA-DR expression by hair follicle keratinocytes in alopecia areata: evidence that it is secondary to the lymphoid infiltration. J Invest Dermatol 1988;90:193—200. [10] Brocker EB, Echternacht-Happle K, Hamm H, Happle R. Abnormal expression of class I and class II major histocompatibility antigens in alopecia areata: modulation by topical immunotherapy. J Invest Dermatol 1987;88:564—8.
Kanlaya Tanyasiria,b,* Kayako Hiraa,b Kouichi Mitsuishia,b Rie Uekia
Iwao Sekigawac Hideoki Ogawaa,b a
Department of Dermatology Juntendo University School of Medicine 2-1-1 Hongo, Bunkyo-ku Tokyo 112-8421, Japan b
Atopy (Allergy) Research Center Juntendo University School of Medicine Tokyo, Japan c
Department of Medicine Juntendo University Urayasu Hospital Chiba, Japan *Corresponding author. Tel.: +81 03 5802 1591 fax: +81 03 3813 5512 E-mail address: [email protected] (K. Tanyasiri) 26 May 2004
www.intl.elsevierhealth.com/journals/jods
LETTER TO THE EDITOR Interleukin-16 in patients with alopecia areata The details of the pathogenesis of alopecia areata (AA) still remain unclear. However, several studies have indicated that AA is an organ-specific autoimmune disease and that T cells (especially CD8+ T cells) may play an important role in its development, as well as certain cytokines (such as interleukin (IL)-1 beta, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha) [1,2]. For example, AA is reinduced by the injection of hair folliclespecific CD8+ T cells into scalp biopsy tissue specimens from AA patients grafted into severe combined immunodeficiency (SCID) mice [3]. IL-16 is a soluble ligand of CD4 that can induce the activation and resultant energy (low responsiveness to antigenic stimuli) of CD4+ cells, as well as promoting chemotaxis by CD4+ cells [4,5] The first cellular source of active IL-16 to be identified was activated CD8+ T cells and the IL-16 level in sera and/or foci is known to be elevated with disease activity in certain autoimmune diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), and in allergic diseases including atopic dermatitis and asthma [5—7]. Based on these findings, we investigated the circulating level of IL16 in AA patients to assess its possible pathogenic role in the development of AA. Ninety patients (30 males and 60 females with an average age of 33 years) with AA were involved in this study and the patients were classified into the following two groups according to the previous study with slight modifications [8]. Type 1 (inactive AA with multiple lesions): more than four circular bald patches are observed on the scalp, the hair pull test is negative, and exclamation point hair is absent. Patients with chronic alopecia universalis (AU; patients who had not shown any new hair growth for 18 months) were also classified into this type. Type 2 (active AA with multiple lesions): more than four bald circular patches and a positive hair pull test. Patients with alopecia totalis (AT) who had
complete baldness localized to the scalp were also classified into this type. The serum level of IL-16 was measured by a sandwich enzyme-linked immunosorbent assay (ELISA) (CytoscreenTM hIL-16 kit, Biosource International, Camarillo, CA, USA) [5]. Flow cytometry analysis was performed using a FACStar plus (Becton Dickinson, San Jose, CA, USA) with PE-labelled anti-CD4 and anti-CD8 monoclonal antibodies (Becton Dickinson), and a FITClabelled anti-HLA-DR antibody (Becton Dickinson) was also used for double staining in some experiments. Statistical analysis (Student’s t-test and Peason’s correlation coefficient analysis) was performed with commercially available statistical software (SPSS, Chicago, IL, USA), and p < 0.05 was considered to indicate significance. The IL-16 level found in type 2 (active) patients was significantly higher than in normal individuals or type 1 (inactive) patients (p < 0.05), while there was no significant difference of IL-16 between normal controls and type 1 patients (Fig. 1). The main source of IL-16 is thought to be activated CD8+ T cells, so we examined the relationship between the IL-16 level and HLA-DR expression (which generally occurs in the active phase of the cell cycle; G1A) by T cells in each patient group. A significant correlation between HLA-DR expression by CD8+ T cells and the IL-16 level was observed in type 2 patients (p < 0.05, r = 0.353), but was not recognized in type 1 patients (Table 1). Regarding CD4+ T cells, there was no significant correlation between HLA-DR expression and the serum IL-16 level in either type 1 or 2 patients (data not shown). Our data indicated that there is an increase of the circulating IL-16 level in AA patients along with disease activity and the IL-16 level is related to the presence of HLA-DR+CD8+ T cells. Supporting this concept, ectopic expression of HLA-DR (a class II major histocompatibility antigen) is observed in perifollicular lymphocytes invading AA lesions [9], as well as an increase of class I antigens [10]. Autoantigens are generally presented with class I major histocompatibility antigens and recognized by CD8+ T cells, leading to the activation (implied by HLA-DR
0923-1811/$30.00 # 2004 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jdermsci.2004.09.006
56
Letter to the Editor
Table 1 Relationship between IL-16 and HLA-DR expression by CD8+ T cells in AA patients p value*
Mean value (range) Inactive (n = 16) Active (n = 32) *
IL-16 (pg/dl)
HLA-DR on CD8+ T (%)
73.01 (48.34 97.68) 171.99 (144.92 199.06)
6.06 (1.9 5.49 (1.1
12.4) 13.5)
>0.05 <0.05
IL-16 concentration vs. HLA-DR expression.
expression) of CD8+ T cells [5]. Thus, the pathogenic role of CD8+ Tcells in AA patients may partly involve production of cytokines (including IL-16) by these activated cells after stimulation with several types of auto-antigens. A similar relationship between IL-16 and activated CD8+ T cells has been suggested to have a role in the etiology of SLE, which is a representative autoimmune disease [5]. In RA, however, adoptive transfer of synovial tissue CD8+ Tcells and IL-16 derived from these cells actually reduces disease activity in the synovium of model mice [6]. This may be explained by the concept that IL-16mediated CD4+ T cell activation and consequent
energy cause a decrease of the CD4+ T cell response to arthritogenic antigens in the synovium [6]. Thus, IL-16 appears to play opposing roles (proinflammatory or antiinflammatory effect) in different disorders. The findings obtained from transfer of CD8+ T cells into AA scalp-SCID mice, as described above [3], seem to indicate that IL-16 acts as a proinflammatory cytokine in the development of AA. However, we cannot also completely neglect the possibility of an antiinflammatory role of IL-16 in AA, because IL-16 can inhibit the production of AApromoting cytokines such as IL-1, IFN-gamma, and TNF-alpha [6]. IL-16 seems to be a useful indicator of the activity of AA and that it may play an important role in the development of this disease. Further investigations are required to clarify the pathogenic role and clinical significance of IL-16, and these findings may provide important clues to assist in the development of new therapeutic strategies for patients with AA.
Acknowledgement This work was supported by the grants from The Institute for Environmental and Gender-specific Medicine, Juntendo University School of Medicine.
References
Fig. 1 Serum levels of IL-16 in healthy controls and AA patients. Bars indicate mean values in each group. Absolute numbers of mean value standard deviation are as follows: control, 74.31 51.86 pg/dl; inactive AA, 72.56 75.13 pg/dl; active AA, 153.62 137.19 pg/dl.
[1] Paus R, Slominski A, Czarnetzki BM. Is alopecia areata an autoimmune-response against melanogenesis-related proteins, exposed by abnormal MHC class I expression in the anagen hair bulb? Yale J Biol Med 1993;66(6):541—54. [2] Hoffmann R, Wenzel E, Huth A, et al. Cytokine mRNA levels in Alopecia areata before and after treatment with the contact allergen diphenylcyclopropenone. J Invest Dermatol 1994;103:530—3. [3] Gilhar A, Shalaginov R, Assy B, Serafimovich S, Kalish RS. Alopecia areata is a T-lymphocyte mediated autoimmune disease: lesional human T-lymphocytes transfer alopecia areata to human skin grafts on SCID mice. J Investig Dermatol Symp Proc 1999;4:207—10. [4] Center DM, Kornfeld H, Cruikshank WW. Interleukin 16 and its function as a CD4 ligand. Immunol Today 1996;17:476— 81.
Letter to the Editor
57
[5] Sekigawa I, Matsushita M, Lee S, et al. A possible pathogenic role of CD8+ T cells and their derived cytokine, IL-16, in SLE. Autoimmunity 2001;33:37—44. [6] Klimiuk PA, Goronzy JJ, Weyand CM. IL-16 as an anti-inflammatory cytokines in rheumatoid synovitis. J Immunol 1999;162:4293—9. [7] Masuda K, Katoh N, Okuda F, Kishimoto S. Increased levels of serum interleukin-16 in adult type atopic dermatitis. Acta Derm Venereol 2003;83:249—53. [8] Imai R, Miura J, Takamori K, Ogawa H. Increased HLA-DR+ T-lymphocyte population in peripheral blood of alopecia areata. Clin Exp Dermatol 1991;16:176—81. [9] Khoury EL, Price VH, Greenspan JS. HLA-DR expression by hair follicle keratinocytes in alopecia areata: evidence that it is secondary to the lymphoid infiltration. J Invest Dermatol 1988;90:193—200. [10] Brocker EB, Echternacht-Happle K, Hamm H, Happle R. Abnormal expression of class I and class II major histocompatibility antigens in alopecia areata: modulation by topical immunotherapy. J Invest Dermatol 1987;88:564—8.
Kanlaya Tanyasiria,b,* Kayako Hiraa,b Kouichi Mitsuishia,b Rie Uekia
Iwao Sekigawac Hideoki Ogawaa,b a
Department of Dermatology Juntendo University School of Medicine 2-1-1 Hongo, Bunkyo-ku Tokyo 112-8421, Japan b
Atopy (Allergy) Research Center Juntendo University School of Medicine Tokyo, Japan c
Department of Medicine Juntendo University Urayasu Hospital Chiba, Japan *Corresponding author. Tel.: +81 03 5802 1591 fax: +81 03 3813 5512 E-mail address: [email protected] (K. Tanyasiri) 26 May 2004