- Email: [email protected]
L18. Granuloma formation in granulomatosis with polyangiitis
J. Charles Jennette University of North Carolina, Department of Pathology and Laboratory Medicine, Chapel Hill, United States Correspondence: J. Charles Jennette, University of North Carolina, Department of Pathology and Laboratory Medicine, Chapel Hill, NC 27599, United States. [email protected] Available online 26 February 2013 ß 2013 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.lpm.2013.01.016
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L18. Granuloma formation in granulomatosis with polyangiitis Extravascular granuloma formation is one of the key features in granulomatosis with polyangiitis (GPA). In most patients, GPA begins in the upper respiratory tract as active, eventually necrotizing extravascular granulomatous disease, with or without local vasculitis. Typically, neutrophilic microabscesses with micronecrosis occur, later bordered by ill-defined granulomas that may proceed to geographic necrosis. In contrast to other types of granulomatous diseases, e.g. sarcoidosis or tuberculosis, the granulomatous inflammation in GPA typically shows very poorly delineated granulomas, or only scattered giant cells, within a dense heterogeneous population of inflammatory bystander cells, mainly lymphocytes, plasma cells, dendritic cells, neutrophils, eosinophils and later fibroblasts (figures 1 and 2). The lymphocytic infiltrate may be organized to form primary and secondary follicles corresponding to ectopic lymphoid tissue. Inflammatory cells, necrosis and fibroblastic proliferates deeply infiltrate the submucous tissues of the upper respiratory tract and may destructively encroach on cartilage and bone with active resorption (figure 2). Morphological studies of granulomatous lesions in GPA must always take the following into account: several different inflammatory cell types constituting ‘‘the’’ granuloma; possible differences in activation profiles and mediator expression (e.g. cytokines) between circulating and lesional inflammatory cells; comparison of seemingly specific phenomena in GPA with other types of purulent and/or granulomatous inflammation. Four important components of the extravascular granulomatous inflammation in GPA will be discussed: neutrophils and micronecrosis; macrophages and giant cells – the granulomatous reaction; ectopic lymphoid tissue: potential source of auto-antigen production; fibroblast mediated destruction of cartilage and bone. Neutrophils and micronecrosis Several studies have shown that in respiratory tract lesions, a purulent neutrophil reaction is an essential feature of GPA [1–3]: small neutrophilic aggregates (microabscesses) around small necrotic areas that contain neutrophilic debris. It has been suggested that micronecrosis with neutrophilic microabscesses constitutes the early phase in the development of the pathognomonic macrophage granuloma in GPA [1]. However, it is not clear how necrotic lesions are induced. Are they solely ANCAinduced and/or do they result from exposure to another initiating injurious agent? Animal models demonstrating PR3-ANCA induced acute pulmonary and renal vascular injury
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[25] Wegener F. Über eine eigenartige rhinogene Granulomatose mit besonderer Beteiligung des Arteriensystems unter den Nieren. Beitr Pathol Anat 1939;102:36-68. [26] Guillevin L, Visser H, Noel LH, Pourrat J, Vernier I, Gayraud M et al. Antineutrophil cytoplasm antibodies in systemic polyarteritis nodosa with and without hepatitis B virus infection and Churg-Strauss syndrome–62 patients. J Rheumatol 1993;20:1345-9. [27] Guillevin L, Lhote F. Distinguishing polyarteritis nodosa from microscopic polyangiitis and implications for treatment. Curr Opin Rheumatol 1995;7:20-4. [28] Kawasaki T. MLNS showing particular skin desquamation from the finger and toe in infants. Allergy 1967;16:178-89. [29] Tanaka N, Naoe S, Kawasaki T. Pathological study on autopsy cases of mucocutaneous lymph node syndrome. J Jap Red Cross Cent Hosp 1971; 2:85-94. [30] Chamberlain JL, Perry LW. Infantile periarteritis nodosa with coronary and brachial aneurysms: a case diagnosed during life. J Pediatr 1971; 78:1039-40. [31] Landing BH, Larson EJ. Are infantile periarteritis nodosa with coronary artery involvement and fatal mucocutaneous lymph node syndrome the same? Comparison of 20 patients from North America with patients from Hawaii and Japan. Pediatrics 1977;59:651-62. [32] Hutchinson J. Diseases of the arteries. On a peculiar form of thrombotic arteritis of the aged which is sometimes productive of gangrene. Arch Surg [London] 1890;1:323-9. [33] Horton BT, Magath TB, Brown GE. Undescribed form of arteritis of temporal vessels. Proc Staff Meet Mayo Clin 1932;7:700-1. [34] Gilmour JR. Giant-cell chronic arteritis. J Pathol 1941;53:263-77. [35] Takayasu M. Case with unusual changes of the central vessels in the retina. Acta Soc Ophthalmol Jpn 1908;12:554-5. [36] Shimizu K, Sano K. Pulseless disease. J Neuropathol Clin Neurol 1951; 1:37-47. [37] Jennette JC, Falk RJ, Andrassy K, Bacon PA, Churg J, Gross WL et al. Nomenclature of systemic vasculitides: the proposal of an international consensus conference. Arthritis Rheum 1994;37:187-92. [38] Jennette JC. Nomenclature and classification of vasculitis: lessons learned from granulomatosis with polyangiitis (Wegener’s granulomatosis). Clin Exp Immunol 2011;164(Suppl. 1):7-10. [39] Falk RJ, Jennette JC. ANCA disease: where is this field going? J Am Soc Nephrol 2010;21:745-52. [40] Falk RJ, Gross WL, Guillevin L, Hoffman G, Jayne DRW, Jennette JC et al. ‘‘Granulomatosis with polyangiitis (Wegener’s)’’: an alternative name for ‘‘Wegener’s granulomatosis’’. A joint proposal of the American College of Rheumatology, the American Society of Nephrology, and the European League Against Rheumatism. Ann Rheum Dis 2011;70:704 [J Am Soc Nephrol 2011;22:587–8, Arthritis Rheum 2011;63:863–4]. [41] Jara LJ, Navarro C, Medina G, Vera-Lastra O, Saavedra MA. Hypocomplementemic urticarial vasculitis syndrome. Curr Rheumatol Rep 2009;11:410-5.
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[(Figure_1)TD$IG]
[(Figure_2)TD$IG]
Figure 1
Figure 2
Nasal mucosa in active granulomatous GPA. Microabscess (neutrophils stained red, arrowheads) within deep submucous tissue, surrounded by macrophage rich poorly defined granulomas (white arrows). Dense lymphoid infiltrate (black arrows). Epithelial surface (E). Naphtol-AS-D-Chloracetateesterase (ASDCL) stain
Nasal bone destruction in active GPA. Arrosion, destruction and medullary infiltration of lamellar bone by fibroblast rich mesenchymal tissue. Hematoxylin and eosin stain
lack extravascular necrotizing granulomatous inflammation of the respiratory tract [4]. Could NETosis play a key role in GPA granuloma? Several recent studies have investigated NETosis as possible pathogen defence mechanism in GPA. ANCA-stimulated neutrophils release neutrophil extracellular traps (NETs), consisting of extracellular fibrous structures of chromatin and various proteins, including PR3 and MPO [5,6]. Kessenbrock et al. [5] have demonstrated NETs in glomerulonephritic lesions in small vessel vasculitis, suggesting a role for PR3-ANCA induced NETosis in the pathogenesis of GPA. Myeloid dendritic cells uploaded with and activated by NETs induced ANCA in susceptible mice [7]. However, no study has investigated NETs in granulomatous extravascular disease in GPA. In contrast to circulating cells that show an increase of IL-17positive T cells in GPA, lesional IL-17 expression in acute ANCAassociated glomerulonephritis has been demonstrated mainly in neutrophils [8]. This is also true in granulomatous lesions of the respiratory tract in GPA. In several other inflammatory diseases, neutrophils have been detected as a source of IL-17. It remains to be examined whether the effects of
neutrophil-derived IL-17 in GPA on inflammatory response differ from those in other diseases. Macrophages and giant cells – the granulomatous reaction In GPA, macrophage accumulations justifying the name of ‘‘granulomatosis’’ constitute only a small minority of cells among a multitude of other inflammatory cells, as has been pointed out very clearly by Jennette [3]. Histologically, the granulomatous nature of the inflammation of GPA is therefore often difficult to perceive. The development of granuloma, i.e. the recruitment of nodularly arranged macrophages and fusion of macrophages to giant cells has been explained as a secondary reactive response to the acute necrotic lesions [1,3,9]. Macrophages and giant cells with phagocytosed apoptotic debris, and apoptotic neutrophils surrounding necrotic areas have been shown in necrotizing granulomatous lesions of the respiratory tract in GPA [3,9]. It has been speculated that local antigen-presentation is maintained by such macrophages [3]. The B cell-activating cytokine APRIL (A PRoliferation-Inducing Ligand), a survival factor for long-lived plasma cells, has been
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Ectopic lymphoid structures: potential source of autoantibody production The inflammatory infiltrate in GPA displays features of ectopic lymphoid-like tissue (ELT) neoformation, which may help to maintain an immunopathological response against an autoantigen, which is otherwise tolerated. PR3-expressing neutrophils, dendritic cells and cells of the adaptive immune response (T- and B-cells, plasma-cells) are clustered in the infiltrate, with lymphocytes frequently organized in follicles [11,12,13]. Local follicle formation and B-cell survival appear to be sustained by cytokines as IL-17, lymphoid chemokines and B-cell survival factors (e.g. APRIL) [10,14]. However, ELT can also occur as reactive lesions in many nonautoimmune chronic inflammatory disorders such as chronic obstructive pulmonary disease [15], and is frequently seen in chronic unspecific rhinosinusitis. Although the mere detection of ELT in granulomatous inflammation of GPA therefore alone cannot prove its significance for auto-antibody production within the granuloma, it has been shown that nasal mucosa can be a place of B lymphocyte maturation, selection and auto-antibody production [11,13,16]. Genetic studies of the overall mutation pattern of CD20+ B-cells and plasma cells from granulomatous GPA tissues show an ongoing selection in Ig V genes resembling that of other autoimmune diseases [17,18].
and pro-inflammatory cytokines IL-6/8 was found in fibroblasts in vivo and in vitro, as well as delayed apoptosis of fibroblasts of GPA patients in vitro [19]. Further studies will be needed to better understand the cellular interactions of ‘‘the granuloma’’ and its mechanisms giving rise to tissue autodestruction and possibly to autoimmunity in GPA. Disclosure of interest : the authors declare that they have no conflicts of interest concerning this article.
References [1]
[2]
[3]
[4]
[5]
[6] [7]
[8]
[9]
[10]
Fibroblast-mediated destruction of cartilage and bone Only recently have fibroblasts received attention as activated effector cells of tissue destruction in GPA, although a prominent and deep submucous fibroblast reaction is a typical feature of chronic upper respiratory tract granulomatous disease (figure 2). Indeed, deep biopsies with cartilage resp. bone destruction typically show a direct contact of the inflammatory infiltrate to nasal skeletal tissue, with fibroblast rich periostal/ perichondral tissue and active destruction of skeletal tissue (figure 2). Necrosis of bone or cartilage as a part of widespread geographical necrosis is seen more rarely. Kesel et al. [19] demonstrated in in vivo experiments that xenografted nasal mucosa of GPA patients showed massive destruction of coimplanted human cartilage, mediated by human fibroblasts. An up-regulated production of metalloproteinases 1, 3 and 13 as mediators of extracellular matrix breakdown at sites of invasion
tome 42 > n84 > avril 2013
[11]
[12]
[13]
[14]
[15] [16]
Mark EJ, Matsubara O, Tan-Liu NS, Fienberg R. The pulmonary biopsy in the early diagnosis of Wegener‘s (pathergic) granulomatosis. Human Pathol 1988;19:1065-71. Devaney KO, Travis WD, Hoffman G, Leavitt R, Lebovics R, Fauci AS. Interpretation of head and neck biopsies in Wegener’s granulomatosis. Am J Surg Pathol 1990;14:555-64. Jennette JC. Nomenclature and classification of vasculitis: lessons learned from granulomatosis with polyangiitis (Wegener‘s granulomatosis). Clin Exp Immunol 2011;164(Suppl. 1):7-10. Little MA, Al-Ani B, Ren S, Al-Nuaimi H, Leite MJr, Alpers CE et al. Antiproteinase 3 anti-neutrophil cytoplasm autoantibodies recapitulate systemic vasculitis in mice with a humanized immune system. PLoS One 2012;7(1):e28626. Kessenbrock K, Krumbholz M, Schönermarck U, Back W, Gross WL, Werb Z et al. Netting neutrophils in autoimmune small-vessel vasculitis. Nat Med 2009;15:623-5. Brinkmann V, Zychlinsky A. Neutrophil extracellular traps: Is immunity the second function of chromatin? J Cell Biol 2012;198:773-83. Sangaletti S, Tripodo C, Chiodoni C, Guarnotta C, Cappetti B, Casalini P et al. Neutrophil extracellular traps mediate transfer of cytoplasmic neutrophil antigens to myeloid dendritic cells toward ANCA induction and associated autoimmunity. Blood 2012;120(15):3007-18. Velden J, Paust HJ, Hoxha E, Turner JE, Steinmetz OM, Wolf G et al. Renal IL-17 expression in human ANCA-associated glomerulonephritis. Am J Physiol Renal Physiol 2012;302(12):F1663-7. Mackiewicz Z, Rimkevicius A, Petersen J, Andersen CB, Dudek E, Vytrasova M. Macrophages overloaded with tissue debris in Wegener’s granulomatosis. Ann Rheum Dis 2005;64(8):1229-32. Zhao Y, Odell E, Choong LM, Barone F, Fields P, Wilkins B et al. Granulomatosis with polyangiitis involves sustained mucosal inflammation that is rich in B-cell survival factors and auto-antigen. Rheumatology (Oxford) 2012;51(9):1580-6. Voswinkel J, Mueller A, Kraemer JA, Lamprecht P, Herlyn K, Holl-Ulrich K et al. B lymphocyte maturation in Wegener’s granulomatosis: a comparative analysis of VH genes from endonasal lesions. Ann Rheum Dis 2006;65:859-64. Capraru C, Müller D, Csernok A, Gross E, Holl-Ulrich WL, Northfield K et al. Expansion of circulating NKG2D+effector memory T-cells and expression of NKG2D-ligand MIC in granulomaous lesions in Wegener’s granulomatosis. Clin Immunol 2008;127(2):144-50. Mueller A, Holl-Ulrich K, Lamprecht P, Gross WL. Germinal centre-like structures in Wegener’s granuloma: the morphological basis for autoimmunity? Rheumatology 2008;47:1111-3. Steinmetz OM, Velden J, Kneissler U, Marx M, Klein A, Helmchen U et al. Analysis and classification of B-cell infiltrates in lupus and ANCAassociated nephritis. Kidney Int 2008;74(4):448-57. Brusselle CG, Joos GF, Bracke KR. New insights into the immunology of chronic obstructive pulmonary disease. Lancet 2011;378:1015-26. Thurner L, Mueller A, Cerutti M, Martin T, Pasquali JL, Gross WL et al. Wegener’s granuloma harbors B lymphocytes with specificities against a
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found in its secreted form within macrophages and giant cells [10]. Therefore in GPA, granuloma could support the generation of an APRIL-rich niche for sustained autoimmune reaction. However, it is not known whether macrophage granuloma is a prerequisite for activity and/or induction of autoimmune processes in affected organs. Apoptotic debris of neutrophils occurs in the course of multiple purulent inflammations at various body sites, among them the respiratory tract. The nature of the antigen remains unknown, as well as the alterations of the immune system in GPA that eventually lead to granuloma formation in GPA.
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proinflammatory transmembrane protein and a tetraspanin. J Autoimmun 2011;36:87-90. [17] Voswinkel J, Assmann G, Held G, Pitann S, Gross WL, Holl-Ulrich K et al. Single cell analysis of B lymphocytes from Wegener’s granulomatosis: B cell receptors display affinity maturation within the granulomatous lesions. Clin Exp Immunol 2008;154:339-45. [18] Zuckerman NS, Hazanov H, Barak M, Edelman H, Hess S, Shcolnik H et al. Somatic hypermutation and antigen-driven selection of B-cells are altered in autoimmune diseases. J Autoimmun 2010;35:325-35. [19] Kesel N, Koehler D, Herich L, Laudien M, Holl-Ulrich K, Jüngel A et al. Cartilage destruction in granulomatosis with polyangiitis (Wegener’s) is mediated by human fibroblasts after transplantation into immunodeficient mice. Am J Pathol 2012;180:2144-55. Konstanze Holl-Ulrich Institute of Pathology, University of Lübeck, Reference Center for Vasculitis Diagnosis, Ratzeburger Allee 160, 23538 Luebeck, Germany Correspondence: Konstanze Holl-Ulrich, Institute of Pathology, University of Lübeck, Reference Center for Vasculitis Diagnosis, Ratzeburger Allee 160, 23538 Luebeck, Germany. [email protected] Available online 26 February 2013 ß 2013 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.lpm.2013.01.017
L19. Lymphoid neogenesis in vascular chronic inflammation
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In contrast to secondary lymphoid organs (SLOs) that arise during development at predetermined locations, the formation of tertiary lymphoid organs (TLOs) can occur in adults at ectopic sites in any tissue in the context of persistent inflammatory disorders, such as autoimmune diseases, cancer, and organ transplantation [1–3]. The molecular mechanisms underlying the organization of chronic inflammatory infiltrates into ectopic lymphoid tissue recapitulate some of those involved in lymphoid organogenesis during development [4,5] and hence this process has been referred to as lymphoid neogenesis. Beyond anatomical similarities with SLOs, ectopic lymphoid tissues are fully functional and support the development of local adaptive immune responses, including the priming of naive lymphocytes [6], generation of memory subsets, and germinal center reactions (clonal expansions, somatic hypermutations, immunoglobulin class switching and antibody production), which are suspected to contribute to the exacerbation of chronic inflammatory diseases [7,8].
Tertiary lymphoid organs (TLOs) in rejected organs We have undertaken several studies in the context of alloimmunity and have demonstrated 1/that the graft is not only the target of the alloimmune response but also a site where this response actually develops, so as to optimize the communication between the targeted tissue and the immune effectors [9], 2/that TLOs provide survival signal to B cells, allowing them to escape rituximab-induced apoptosis, thereby thwarting therapeutic efficiency [10], 3/that anti-MHC humoral response is more intense and more diverse in TLOs [the abnormal activation of CD4+ T cells promotes the development of an exaggerated pathogenic immune humoral response in TLOs due to a defective immune regulation] [11] and the intragraft microenvironment interferes with peripheral deletion of autoreactive immature B cells that, in turn, produce antibodies against intracellular autoantigens [12], 4/that intragraft humoral immune response appears uncoupled from the systemic response and that TLO formation recapitulate organogenesis of SLOs [13]. While these data demonstrate that chronic rejection is associated with the development of lymphoid nodular infiltrates within rejected organs, evidence for the involvement of these lymphoid structures in the rejection process came from a model of rat aortic interposition model where lymphoid nodular infiltrates was evidenced in the adventitia of the chronically rejected aortic grafts [3]. We could demonstrate that nodular lymphoid structures were functional ectopic germinal centers that participate in the rejection process of the grafted organ. In addition, this showed that the vascular stroma was sufficient to promote and support lymphoid neogenesis. Tertiary lymphoid organs (TLOs) in atherothrombosis Interestingly, TLOs are also present in the context of atherothrombosis. Indeed, TLOs were detected in the adventitia of human atherosclerotic arteries as early as the 1950s [14], a process that has been recently revisited [15–18]. We could also characterize adventitial lymphoid aggregates distributed all along the aortic segment in atherosclerosis-prone ApoE KO mice. These structures were defined as TLOs because they are composed of B cell follicles surrounded by T cells, a prototypic organization reported for ectopic germinal centers [4]. IgM and IgD staining revealed the presence of two subsets of B cells with different maturation states. Moreover, these TLOs included blood vessels, lymphatic networks, and FRC-like cells, suggesting that these aggregates are proper structures to induce and maintain local immune responses. These adventitial blood and lymphatic networks are essential for the recruitment and drainage of immune effectors [19–22]. Interestingly, the TLOs were polarized towards the media, suggesting that effectors inside the aortic wall may be involved in the lymphangiogenesis and angiogenesis associated with the formation of adventitial TLOs. In this respect, it is important to note that
tome 42 > n84 > avril 2013
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L18. Granuloma formation in granulomatosis with polyangiitis Extravascular granuloma formation is one of the key features in granulomatosis with polyangiitis (GPA). In most patients, GPA begins in the upper respiratory tract as active, eventually necrotizing extravascular granulomatous disease, with or without local vasculitis. Typically, neutrophilic microabscesses with micronecrosis occur, later bordered by ill-defined granulomas that may proceed to geographic necrosis. In contrast to other types of granulomatous diseases, e.g. sarcoidosis or tuberculosis, the granulomatous inflammation in GPA typically shows very poorly delineated granulomas, or only scattered giant cells, within a dense heterogeneous population of inflammatory bystander cells, mainly lymphocytes, plasma cells, dendritic cells, neutrophils, eosinophils and later fibroblasts (figures 1 and 2). The lymphocytic infiltrate may be organized to form primary and secondary follicles corresponding to ectopic lymphoid tissue. Inflammatory cells, necrosis and fibroblastic proliferates deeply infiltrate the submucous tissues of the upper respiratory tract and may destructively encroach on cartilage and bone with active resorption (figure 2). Morphological studies of granulomatous lesions in GPA must always take the following into account: several different inflammatory cell types constituting ‘‘the’’ granuloma; possible differences in activation profiles and mediator expression (e.g. cytokines) between circulating and lesional inflammatory cells; comparison of seemingly specific phenomena in GPA with other types of purulent and/or granulomatous inflammation. Four important components of the extravascular granulomatous inflammation in GPA will be discussed: neutrophils and micronecrosis; macrophages and giant cells – the granulomatous reaction; ectopic lymphoid tissue: potential source of auto-antigen production; fibroblast mediated destruction of cartilage and bone. Neutrophils and micronecrosis Several studies have shown that in respiratory tract lesions, a purulent neutrophil reaction is an essential feature of GPA [1–3]: small neutrophilic aggregates (microabscesses) around small necrotic areas that contain neutrophilic debris. It has been suggested that micronecrosis with neutrophilic microabscesses constitutes the early phase in the development of the pathognomonic macrophage granuloma in GPA [1]. However, it is not clear how necrotic lesions are induced. Are they solely ANCAinduced and/or do they result from exposure to another initiating injurious agent? Animal models demonstrating PR3-ANCA induced acute pulmonary and renal vascular injury
555
[25] Wegener F. Über eine eigenartige rhinogene Granulomatose mit besonderer Beteiligung des Arteriensystems unter den Nieren. Beitr Pathol Anat 1939;102:36-68. [26] Guillevin L, Visser H, Noel LH, Pourrat J, Vernier I, Gayraud M et al. Antineutrophil cytoplasm antibodies in systemic polyarteritis nodosa with and without hepatitis B virus infection and Churg-Strauss syndrome–62 patients. J Rheumatol 1993;20:1345-9. [27] Guillevin L, Lhote F. Distinguishing polyarteritis nodosa from microscopic polyangiitis and implications for treatment. Curr Opin Rheumatol 1995;7:20-4. [28] Kawasaki T. MLNS showing particular skin desquamation from the finger and toe in infants. Allergy 1967;16:178-89. [29] Tanaka N, Naoe S, Kawasaki T. Pathological study on autopsy cases of mucocutaneous lymph node syndrome. J Jap Red Cross Cent Hosp 1971; 2:85-94. [30] Chamberlain JL, Perry LW. Infantile periarteritis nodosa with coronary and brachial aneurysms: a case diagnosed during life. J Pediatr 1971; 78:1039-40. [31] Landing BH, Larson EJ. Are infantile periarteritis nodosa with coronary artery involvement and fatal mucocutaneous lymph node syndrome the same? Comparison of 20 patients from North America with patients from Hawaii and Japan. Pediatrics 1977;59:651-62. [32] Hutchinson J. Diseases of the arteries. On a peculiar form of thrombotic arteritis of the aged which is sometimes productive of gangrene. Arch Surg [London] 1890;1:323-9. [33] Horton BT, Magath TB, Brown GE. Undescribed form of arteritis of temporal vessels. Proc Staff Meet Mayo Clin 1932;7:700-1. [34] Gilmour JR. Giant-cell chronic arteritis. J Pathol 1941;53:263-77. [35] Takayasu M. Case with unusual changes of the central vessels in the retina. Acta Soc Ophthalmol Jpn 1908;12:554-5. [36] Shimizu K, Sano K. Pulseless disease. J Neuropathol Clin Neurol 1951; 1:37-47. [37] Jennette JC, Falk RJ, Andrassy K, Bacon PA, Churg J, Gross WL et al. Nomenclature of systemic vasculitides: the proposal of an international consensus conference. Arthritis Rheum 1994;37:187-92. [38] Jennette JC. Nomenclature and classification of vasculitis: lessons learned from granulomatosis with polyangiitis (Wegener’s granulomatosis). Clin Exp Immunol 2011;164(Suppl. 1):7-10. [39] Falk RJ, Jennette JC. ANCA disease: where is this field going? J Am Soc Nephrol 2010;21:745-52. [40] Falk RJ, Gross WL, Guillevin L, Hoffman G, Jayne DRW, Jennette JC et al. ‘‘Granulomatosis with polyangiitis (Wegener’s)’’: an alternative name for ‘‘Wegener’s granulomatosis’’. A joint proposal of the American College of Rheumatology, the American Society of Nephrology, and the European League Against Rheumatism. Ann Rheum Dis 2011;70:704 [J Am Soc Nephrol 2011;22:587–8, Arthritis Rheum 2011;63:863–4]. [41] Jara LJ, Navarro C, Medina G, Vera-Lastra O, Saavedra MA. Hypocomplementemic urticarial vasculitis syndrome. Curr Rheumatol Rep 2009;11:410-5.
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[(Figure_1)TD$IG]
[(Figure_2)TD$IG]
Figure 1
Figure 2
Nasal mucosa in active granulomatous GPA. Microabscess (neutrophils stained red, arrowheads) within deep submucous tissue, surrounded by macrophage rich poorly defined granulomas (white arrows). Dense lymphoid infiltrate (black arrows). Epithelial surface (E). Naphtol-AS-D-Chloracetateesterase (ASDCL) stain
Nasal bone destruction in active GPA. Arrosion, destruction and medullary infiltration of lamellar bone by fibroblast rich mesenchymal tissue. Hematoxylin and eosin stain
lack extravascular necrotizing granulomatous inflammation of the respiratory tract [4]. Could NETosis play a key role in GPA granuloma? Several recent studies have investigated NETosis as possible pathogen defence mechanism in GPA. ANCA-stimulated neutrophils release neutrophil extracellular traps (NETs), consisting of extracellular fibrous structures of chromatin and various proteins, including PR3 and MPO [5,6]. Kessenbrock et al. [5] have demonstrated NETs in glomerulonephritic lesions in small vessel vasculitis, suggesting a role for PR3-ANCA induced NETosis in the pathogenesis of GPA. Myeloid dendritic cells uploaded with and activated by NETs induced ANCA in susceptible mice [7]. However, no study has investigated NETs in granulomatous extravascular disease in GPA. In contrast to circulating cells that show an increase of IL-17positive T cells in GPA, lesional IL-17 expression in acute ANCAassociated glomerulonephritis has been demonstrated mainly in neutrophils [8]. This is also true in granulomatous lesions of the respiratory tract in GPA. In several other inflammatory diseases, neutrophils have been detected as a source of IL-17. It remains to be examined whether the effects of
neutrophil-derived IL-17 in GPA on inflammatory response differ from those in other diseases. Macrophages and giant cells – the granulomatous reaction In GPA, macrophage accumulations justifying the name of ‘‘granulomatosis’’ constitute only a small minority of cells among a multitude of other inflammatory cells, as has been pointed out very clearly by Jennette [3]. Histologically, the granulomatous nature of the inflammation of GPA is therefore often difficult to perceive. The development of granuloma, i.e. the recruitment of nodularly arranged macrophages and fusion of macrophages to giant cells has been explained as a secondary reactive response to the acute necrotic lesions [1,3,9]. Macrophages and giant cells with phagocytosed apoptotic debris, and apoptotic neutrophils surrounding necrotic areas have been shown in necrotizing granulomatous lesions of the respiratory tract in GPA [3,9]. It has been speculated that local antigen-presentation is maintained by such macrophages [3]. The B cell-activating cytokine APRIL (A PRoliferation-Inducing Ligand), a survival factor for long-lived plasma cells, has been
tome 42 > n84 > avril 2013
Ectopic lymphoid structures: potential source of autoantibody production The inflammatory infiltrate in GPA displays features of ectopic lymphoid-like tissue (ELT) neoformation, which may help to maintain an immunopathological response against an autoantigen, which is otherwise tolerated. PR3-expressing neutrophils, dendritic cells and cells of the adaptive immune response (T- and B-cells, plasma-cells) are clustered in the infiltrate, with lymphocytes frequently organized in follicles [11,12,13]. Local follicle formation and B-cell survival appear to be sustained by cytokines as IL-17, lymphoid chemokines and B-cell survival factors (e.g. APRIL) [10,14]. However, ELT can also occur as reactive lesions in many nonautoimmune chronic inflammatory disorders such as chronic obstructive pulmonary disease [15], and is frequently seen in chronic unspecific rhinosinusitis. Although the mere detection of ELT in granulomatous inflammation of GPA therefore alone cannot prove its significance for auto-antibody production within the granuloma, it has been shown that nasal mucosa can be a place of B lymphocyte maturation, selection and auto-antibody production [11,13,16]. Genetic studies of the overall mutation pattern of CD20+ B-cells and plasma cells from granulomatous GPA tissues show an ongoing selection in Ig V genes resembling that of other autoimmune diseases [17,18].
and pro-inflammatory cytokines IL-6/8 was found in fibroblasts in vivo and in vitro, as well as delayed apoptosis of fibroblasts of GPA patients in vitro [19]. Further studies will be needed to better understand the cellular interactions of ‘‘the granuloma’’ and its mechanisms giving rise to tissue autodestruction and possibly to autoimmunity in GPA. Disclosure of interest : the authors declare that they have no conflicts of interest concerning this article.
References [1]
[2]
[3]
[4]
[5]
[6] [7]
[8]
[9]
[10]
Fibroblast-mediated destruction of cartilage and bone Only recently have fibroblasts received attention as activated effector cells of tissue destruction in GPA, although a prominent and deep submucous fibroblast reaction is a typical feature of chronic upper respiratory tract granulomatous disease (figure 2). Indeed, deep biopsies with cartilage resp. bone destruction typically show a direct contact of the inflammatory infiltrate to nasal skeletal tissue, with fibroblast rich periostal/ perichondral tissue and active destruction of skeletal tissue (figure 2). Necrosis of bone or cartilage as a part of widespread geographical necrosis is seen more rarely. Kesel et al. [19] demonstrated in in vivo experiments that xenografted nasal mucosa of GPA patients showed massive destruction of coimplanted human cartilage, mediated by human fibroblasts. An up-regulated production of metalloproteinases 1, 3 and 13 as mediators of extracellular matrix breakdown at sites of invasion
tome 42 > n84 > avril 2013
[11]
[12]
[13]
[14]
[15] [16]
Mark EJ, Matsubara O, Tan-Liu NS, Fienberg R. The pulmonary biopsy in the early diagnosis of Wegener‘s (pathergic) granulomatosis. Human Pathol 1988;19:1065-71. Devaney KO, Travis WD, Hoffman G, Leavitt R, Lebovics R, Fauci AS. Interpretation of head and neck biopsies in Wegener’s granulomatosis. Am J Surg Pathol 1990;14:555-64. Jennette JC. Nomenclature and classification of vasculitis: lessons learned from granulomatosis with polyangiitis (Wegener‘s granulomatosis). Clin Exp Immunol 2011;164(Suppl. 1):7-10. Little MA, Al-Ani B, Ren S, Al-Nuaimi H, Leite MJr, Alpers CE et al. Antiproteinase 3 anti-neutrophil cytoplasm autoantibodies recapitulate systemic vasculitis in mice with a humanized immune system. PLoS One 2012;7(1):e28626. Kessenbrock K, Krumbholz M, Schönermarck U, Back W, Gross WL, Werb Z et al. Netting neutrophils in autoimmune small-vessel vasculitis. Nat Med 2009;15:623-5. Brinkmann V, Zychlinsky A. Neutrophil extracellular traps: Is immunity the second function of chromatin? J Cell Biol 2012;198:773-83. Sangaletti S, Tripodo C, Chiodoni C, Guarnotta C, Cappetti B, Casalini P et al. Neutrophil extracellular traps mediate transfer of cytoplasmic neutrophil antigens to myeloid dendritic cells toward ANCA induction and associated autoimmunity. Blood 2012;120(15):3007-18. Velden J, Paust HJ, Hoxha E, Turner JE, Steinmetz OM, Wolf G et al. Renal IL-17 expression in human ANCA-associated glomerulonephritis. Am J Physiol Renal Physiol 2012;302(12):F1663-7. Mackiewicz Z, Rimkevicius A, Petersen J, Andersen CB, Dudek E, Vytrasova M. Macrophages overloaded with tissue debris in Wegener’s granulomatosis. Ann Rheum Dis 2005;64(8):1229-32. Zhao Y, Odell E, Choong LM, Barone F, Fields P, Wilkins B et al. Granulomatosis with polyangiitis involves sustained mucosal inflammation that is rich in B-cell survival factors and auto-antigen. Rheumatology (Oxford) 2012;51(9):1580-6. Voswinkel J, Mueller A, Kraemer JA, Lamprecht P, Herlyn K, Holl-Ulrich K et al. B lymphocyte maturation in Wegener’s granulomatosis: a comparative analysis of VH genes from endonasal lesions. Ann Rheum Dis 2006;65:859-64. Capraru C, Müller D, Csernok A, Gross E, Holl-Ulrich WL, Northfield K et al. Expansion of circulating NKG2D+effector memory T-cells and expression of NKG2D-ligand MIC in granulomaous lesions in Wegener’s granulomatosis. Clin Immunol 2008;127(2):144-50. Mueller A, Holl-Ulrich K, Lamprecht P, Gross WL. Germinal centre-like structures in Wegener’s granuloma: the morphological basis for autoimmunity? Rheumatology 2008;47:1111-3. Steinmetz OM, Velden J, Kneissler U, Marx M, Klein A, Helmchen U et al. Analysis and classification of B-cell infiltrates in lupus and ANCAassociated nephritis. Kidney Int 2008;74(4):448-57. Brusselle CG, Joos GF, Bracke KR. New insights into the immunology of chronic obstructive pulmonary disease. Lancet 2011;378:1015-26. Thurner L, Mueller A, Cerutti M, Martin T, Pasquali JL, Gross WL et al. Wegener’s granuloma harbors B lymphocytes with specificities against a
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found in its secreted form within macrophages and giant cells [10]. Therefore in GPA, granuloma could support the generation of an APRIL-rich niche for sustained autoimmune reaction. However, it is not known whether macrophage granuloma is a prerequisite for activity and/or induction of autoimmune processes in affected organs. Apoptotic debris of neutrophils occurs in the course of multiple purulent inflammations at various body sites, among them the respiratory tract. The nature of the antigen remains unknown, as well as the alterations of the immune system in GPA that eventually lead to granuloma formation in GPA.
Lectures
16th International Vasculitis & ANCA Workshop
Lectures
proinflammatory transmembrane protein and a tetraspanin. J Autoimmun 2011;36:87-90. [17] Voswinkel J, Assmann G, Held G, Pitann S, Gross WL, Holl-Ulrich K et al. Single cell analysis of B lymphocytes from Wegener’s granulomatosis: B cell receptors display affinity maturation within the granulomatous lesions. Clin Exp Immunol 2008;154:339-45. [18] Zuckerman NS, Hazanov H, Barak M, Edelman H, Hess S, Shcolnik H et al. Somatic hypermutation and antigen-driven selection of B-cells are altered in autoimmune diseases. J Autoimmun 2010;35:325-35. [19] Kesel N, Koehler D, Herich L, Laudien M, Holl-Ulrich K, Jüngel A et al. Cartilage destruction in granulomatosis with polyangiitis (Wegener’s) is mediated by human fibroblasts after transplantation into immunodeficient mice. Am J Pathol 2012;180:2144-55. Konstanze Holl-Ulrich Institute of Pathology, University of Lübeck, Reference Center for Vasculitis Diagnosis, Ratzeburger Allee 160, 23538 Luebeck, Germany Correspondence: Konstanze Holl-Ulrich, Institute of Pathology, University of Lübeck, Reference Center for Vasculitis Diagnosis, Ratzeburger Allee 160, 23538 Luebeck, Germany. [email protected] Available online 26 February 2013 ß 2013 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.lpm.2013.01.017
L19. Lymphoid neogenesis in vascular chronic inflammation
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In contrast to secondary lymphoid organs (SLOs) that arise during development at predetermined locations, the formation of tertiary lymphoid organs (TLOs) can occur in adults at ectopic sites in any tissue in the context of persistent inflammatory disorders, such as autoimmune diseases, cancer, and organ transplantation [1–3]. The molecular mechanisms underlying the organization of chronic inflammatory infiltrates into ectopic lymphoid tissue recapitulate some of those involved in lymphoid organogenesis during development [4,5] and hence this process has been referred to as lymphoid neogenesis. Beyond anatomical similarities with SLOs, ectopic lymphoid tissues are fully functional and support the development of local adaptive immune responses, including the priming of naive lymphocytes [6], generation of memory subsets, and germinal center reactions (clonal expansions, somatic hypermutations, immunoglobulin class switching and antibody production), which are suspected to contribute to the exacerbation of chronic inflammatory diseases [7,8].
Tertiary lymphoid organs (TLOs) in rejected organs We have undertaken several studies in the context of alloimmunity and have demonstrated 1/that the graft is not only the target of the alloimmune response but also a site where this response actually develops, so as to optimize the communication between the targeted tissue and the immune effectors [9], 2/that TLOs provide survival signal to B cells, allowing them to escape rituximab-induced apoptosis, thereby thwarting therapeutic efficiency [10], 3/that anti-MHC humoral response is more intense and more diverse in TLOs [the abnormal activation of CD4+ T cells promotes the development of an exaggerated pathogenic immune humoral response in TLOs due to a defective immune regulation] [11] and the intragraft microenvironment interferes with peripheral deletion of autoreactive immature B cells that, in turn, produce antibodies against intracellular autoantigens [12], 4/that intragraft humoral immune response appears uncoupled from the systemic response and that TLO formation recapitulate organogenesis of SLOs [13]. While these data demonstrate that chronic rejection is associated with the development of lymphoid nodular infiltrates within rejected organs, evidence for the involvement of these lymphoid structures in the rejection process came from a model of rat aortic interposition model where lymphoid nodular infiltrates was evidenced in the adventitia of the chronically rejected aortic grafts [3]. We could demonstrate that nodular lymphoid structures were functional ectopic germinal centers that participate in the rejection process of the grafted organ. In addition, this showed that the vascular stroma was sufficient to promote and support lymphoid neogenesis. Tertiary lymphoid organs (TLOs) in atherothrombosis Interestingly, TLOs are also present in the context of atherothrombosis. Indeed, TLOs were detected in the adventitia of human atherosclerotic arteries as early as the 1950s [14], a process that has been recently revisited [15–18]. We could also characterize adventitial lymphoid aggregates distributed all along the aortic segment in atherosclerosis-prone ApoE KO mice. These structures were defined as TLOs because they are composed of B cell follicles surrounded by T cells, a prototypic organization reported for ectopic germinal centers [4]. IgM and IgD staining revealed the presence of two subsets of B cells with different maturation states. Moreover, these TLOs included blood vessels, lymphatic networks, and FRC-like cells, suggesting that these aggregates are proper structures to induce and maintain local immune responses. These adventitial blood and lymphatic networks are essential for the recruitment and drainage of immune effectors [19–22]. Interestingly, the TLOs were polarized towards the media, suggesting that effectors inside the aortic wall may be involved in the lymphangiogenesis and angiogenesis associated with the formation of adventitial TLOs. In this respect, it is important to note that
tome 42 > n84 > avril 2013