Heterogeneity of CD4 and CD8+ memory T cells in localized and generalized Wegener's granulomatosis

Longitudinal monitoring of circulating immune cell phenotypes in anti-neutrophil cytoplasmic antibody-associated vasculitis

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a necrotizing multiorgan autoimmune disease that affects small- to medium-sized blood vessels. Despite the improvements in treatments, half of the patients with AAV still experience disease relapses. In this review, we focus on peripheral leukocyte properties and phenotypes in patients with AAV. In particular, we explore longitudinal changes in circulating immune cell phenotypes during the active phase of the disease and treatment. The numbers and phenotypes of leukocytes in peripheral blood were differs between AAV and healthy controls, AAV in active versus inactive phase, AAV in treatment responders versus non-responders, and AAV with and without severe infection. Therefore, biomarkers detected in peripheral blood immune cells may be useful for longitudinal monitoring of disease activity in AAV.

Altered circulating CCR6+and CXCR3+ T cell subsets are associated with poor renal prognosis in MPO-ANCA-associated vasculitis

Background

Effector memory T cells are pivotal effectors of adaptive immunity with enhanced migration characteristics and are involved in the pathogenesis of ANCA-associated vasculitis (AAV). The diversity of effector memory T cells in chemokine receptor expression has been well studied in proteinase 3 (PR3)-AAV. However, few studies have been conducted in myeloperoxidase (MPO)-AAV. Here, we characterized chemokine receptor expression on effector memory T cells from patients with active MPO-AAV.

Methods

Clinical data from newly diagnosed MPO-AAV patients and healthy subjects were collected and analyzed. Human peripheral blood mononuclear cells (PBMCs) isolated from patients with active MPO-AAV were analyzed by flow cytometry. The production of effector memory T cell-related chemokines in serum was assessed by ELISA.

Results

We observed decreased percentages of CD4⁺ and CD8⁺ T cells in the peripheral blood, accompanied by a significant decrease in CCR6-expressing T cells but an increase in CXCR3⁺ T cells, in active MPO-AAV. Furthermore, the decrease in CCR6 and increase in CXCR3 expression were mainly limited to effector memory T cells. Consistent with this finding, the serum level of CCL20 was increased. In addition, a decreasing trend in the T_EM17 cell frequency, with concomitant increases in the frequencies of CD4⁺ T_EM1 and CD4⁺ T_EM17.1 cells, was observed when T cell functional subsets were defined by chemokine receptor expression. Moreover, the proportions of peripheral CD8⁺ T cells and CD4⁺ T_EM subsets were correlated with renal prognosis and inflammatory markers.

Conclusions

Our data indicate that dysregulated chemokine receptor expression on CD4⁺ and CD8⁺ effector memory T cells and aberrant distribution of functional CD4⁺ T cell subsets in patients with active MPO-AAV have critical roles related to kidney survival.

CD8+ T Cells in GCA and GPA: Bystanders or Active Contributors?

Vasculitis refers to inflammation of blood vessels and can cause a variety of serious complications depending on which vessels are affected. Two different forms of vasculitis are Giant Cell Arteritis (GCA) and Granulomatosis with Polyangiitis (GPA). GCA is the most common form of vasculitis in adults affecting the large arteries and can lead to visual impairment and development of aneurysms. GPA affects small- and medium-sized blood vessels predominantly in the lungs and kidneys resulting in organ failure. Both diseases can potentially be fatal. Although the pathogenesis of GCA and GPA are incompletely understood, a prominent role for CD4+ T cells has been implicated in both diseases. More recently, the role of CD8+ T cells has gained renewed interest. CD8+ T cells are important players in the adaptive immune response against intracellular microorganisms. After a general introduction on the different forms of vasculitis and their association with infections and CD8+ T cells, we review the current knowledge on CD8+ T-cell involvement in the immunopathogenesis of GCA and GPA focusing on phenotypic and functional features of circulating and lesional CD8+ T cells. Furthermore, we discuss to which extent aging is associated with CD8+ T-cell phenotype and function in GCA and GPA.

Pathogenesis of ANCA-Associated Pulmonary Vasculitis

Antineutrophil cytoplasmic antibodies (ANCAs) are autoantibodies specific for antigens located in the cytoplasmic granules of neutrophils and lysosomes of monocytes. ANCAs are associated with a spectrum of necrotizing vasculitis that includes granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. Pulmonary vasculitis and related extravascular inflammation and fibrosis are frequent components of ANCA vasculitis. In this review, we detail the factors that have been associated with the origin of the ANCA autoimmune response and summarize the most relevant clinical observations, in vitro evidence, and animal studies strongly indicating the pathogenic potential of ANCA. In addition, we describe the putative sequence of pathogenic mechanisms driven by ANCA-induced activation of neutrophils that result in small vessel necrotizing vasculitis and extravascular granulomatous necrotizing inflammation.

Chemokine receptor co-expression reveals aberrantly distributed TH effector memory cells in GPA patients

Background

Persistent expansion of circulating CD4⁺ effector memory T cells (T_EM) in patients with granulomatosis with polyangiitis (GPA) suggests their fundamental role in disease pathogenesis. Recent studies have shown that distinct functional CD4⁺ T_EM cell subsets can be identified based on expression patterns of chemokine receptors. The current study aimed to determine different CD4⁺ T_EM cell subsets based on chemokine receptor expression in peripheral blood of GPA patients. Identification of particular circulating CD4⁺ T_EM cells subsets may reveal distinct contributions of specific CD4⁺ T_EM subsets to the disease pathogenesis in GPA.

Method

Peripheral blood of 63 GPA patients in remission and 42 age- and sex-matched healthy controls was stained immediately after blood withdrawal with fluorochrome-conjugated antibodies for cell surface markers (CD3, CD4, CD45RO) and chemokine receptors (CCR4, CCR6, CCR7, CRTh2, CXCR3) followed by flow cytometry analysis. CD4⁺ T_EM memory cells (CD3⁺CD4⁺CD45RO⁺CCR7^-) were gated, and the expression patterns of chemokine receptors CXCR3⁺CCR4^-CCR6^-CRTh2^-, CXCR3^-CCR4⁺CCR6^-CRTh2⁺, CXCR3^-CCR4⁺CCR6⁺CRTh2^-, and CXCR3⁺CCR4^-CCR6⁺CRTh2^- were used to distinguish T_EM1, T_EM2, T_EM17, and T_EM17.1 cells, respectively.

Results

The percentage of CD4⁺ T_EM cells was significantly increased in GPA patients in remission compared to HCs. Chemokine receptor co-expression analysis within the CD4⁺ T_EM cell population demonstrated a significant increase in the proportion of T_EM17 cells with a concomitant significant decrease in the T_EM1 cells in GPA patients compared to HC. The percentage of T_EM17 cells correlated negatively with T_EM1 cells in GPA patients. Moreover, the circulating proportion of T_EM17 cells showed a positive correlation with the number of organs involved and an association with the tendency to relapse in GPA patients. Interestingly, the aberrant distribution of T_EM1 and T_EM17 cells is modulated in CMV- seropositive GPA patients.

Conclusions

Our data demonstrates the identification of different CD4⁺ T_EM cell subsets in peripheral blood of GPA patients based on chemokine receptor co-expression analysis. The aberrant balance between T_EM1 and T_EM17 cells in remission GPA patients, showed to be associated with disease pathogenesis in relation to organ involvement, and tendency to relapse.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1343-8) contains supplementary material, which is available to authorized users.

Dysregulated Responsiveness of Circulating Dendritic Cells to Toll-Like Receptors in ANCA-Associated Vasculitis

Objective

Dendritic cells (DCs) are critical effectors of innate and adaptive immunity playing crucial roles in autoimmune responses. We previously showed that blood DC numbers were reduced in autoimmune antineutrophil cytoplasmic autoantibody-associated vasculitis (AAV). Here, we assessed toll-like receptor (TLR) responsiveness of blood DCs from patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA).

Methods

Blood samples from healthy controls (HCs), GPA, or MPA patients, without treatment, during acute phase (AP) or remission phase (RP) were analyzed. Cytokine production by DCs and T cells was assessed on whole blood by flow cytometry after TLRs or polyclonal stimulation, respectively.

Results

We first showed that GPA and MPA are associated with a decreased blood DC number during AP. Conventional DCs (cDCs) from patients with GPA and MPA in AP exhibited a profound decrease of IL-12/IL-23p40 production after TLR3, 4, or 7/8 stimulation compared to patients in remission and HC, with a return to normal values in RP. TNFα secretion was also affected, with a decrease in cDCs from GPA patients in AP after TLR3 stimulation but an increase after TLR7/8 stimulation. By contrast, the responsiveness of plasmacytoid DCs to TLR7 and 9 was only marginally affected. Finally, we observed that IFNγ-producing CD4⁺ T cell frequency was significantly lower in AP-GPA patients than in HC.

Conclusion

We describe, for the first time, a dysregulated response to TLRs of circulating DCs in AAV patients mostly affecting cDCs that exhibit an unexpected reduced inflammatory cytokine secretion possibly contributing to an altered Th cell response.

Granulomatosis with polyangiitis (Wegener granulomatosis) as a differential diagnosis of sternal osteomyelitis: the challenges in diagnosis

Although granulomatosis with polyangiitis (GPA) can affect a large number of organ systems and produce a broad spectrum of clinical symptoms, skeletal involvement is very rare, with the exception of facial bone involvement associated with destructive nasal and sinus inflammation. We describe here a 54-year-old man with sternal osteomyelitis and destructive arthritis around the sternoclavicular joint. Despite antibiotics and conventional immunosuppressive treatment, his symptoms deteriorated, and a new mass-like lung lesion was developed. A histopathologic analysis of the lung mass revealed chronic granulomatous inflammation with fibrinoid necrosis, and he was diagnosed with GPA. When a patient with a destructive inflammatory lesion has negative culture results and no response to conventional therapy, we propose that an aggressive approach is necessary for a pathologic diagnosis to exclude the possibility of GPA.

Increased frequency of CCR4+ and CCR6+ memory T-cells including CCR7+CD45RAmed very early memory cells in granulomatosis with polyangiitis (Wegener's)

INTRODUCTION

Chemokine receptors play an important role in mediating the recruitment of T cells to inflammatory sites. Previously, small proportions of circulating Th1-type CCR5+ and Th2-type CCR3+ cells have been shown in granulomatosis with polyangiitis (GPA). Wondering to what extent CCR4 and CCR6 expression could also be implicated in T cell recruitment to inflamed sites in GPA, we investigated the expression of CCR4 and CCR6 on T cells and its association with T cell diversity and polarization.

METHODS

Multicolor flow cytometry was used to analyze CCR4, CCR6, and intracellular cytokine expression of T cells from whole blood of GPA-patients (n = 26) and healthy controls (n = 20). CCR7 and CD45RA were included for phenotypic characterization.

RESULTS

We found a significant increase in the percentages of circulating CCR4+ and CCR6+ cells within the total CD4+ T cell population in GPA. In contrast, there was no difference in the percentages of CD8+CCR4+ and CD8+CCR6+ T cells between GPA and healthy controls. CCR4 and CCR6 expression was largely confined to central (TCM) and effector memory T cells (TEM, TEMRA). A significant increase in the frequency of CCR4+ and CCR6+ TEMRA and CCR6+ TCM was shown in GPA. Of note, we could dissect CCR4 and CCR6 expressing CCR7+CD45RAmed very early memory T cells (TVEM) from genuine CCR7+CD45RAhigh naïve T cells lacking CCR4 and CCR6 expression for peripheral tissue-migration within the CCR7+CD45RA+ compartment. The frequencies of CCR4+ and CCR6+ TVEM were also significantly increased in GPA. An increased percentage of IL-17+ and IL-22+ cells was detected in the CCR6+ cell subsets and IL-4+ cells in the CRR4+ cell subset when compared with CD4+ cells lacking CCR4 and CCR6 expression.

CONCLUSIONS

Increased frequencies of circulating CCR4+ and CCR6+ memory T cell subsets including hitherto unreported TVEM suggest persistent T cell activation with the accumulation of CCR4+ and CCR6+ cells in GPA. CCR4 and CCR6 could be involved in the recruitment of T cells including cytokine-producing subsets to inflamed sites in GPA.

The Molecular Biology and Treatment of Systemic Vasculitis in Children

Primary systemic vasculitides are rare in childhood but are associated with significant morbidity and mortality. The cause of the majority of vasculitides is unknown, although it is likely that a complex interaction between environmental factors, such as infections and inherited host responses, triggers the disease and determines the vasculitis phenotype. Several genetic polymorphisms in vasculitides have now been described, which may be relevant in terms of disease predisposition or development of disease complications. Treatment regimens continue to improve with the use of different immunosuppressive medications and newer therapeutic approaches such as biologic agents. This chapter reviews recent studies shedding light on the pathogenesis of vasculitis with emphasis on molecular biology where known, and summarizes current treatment strategies. We discuss new emerging challenges particularly with respect to the long-term cardiovascular morbidity for children with systemic vasculitis and emphasize the importance of future international multicenter collaborative studies to further increase and standardize the scientific base investigating and treating childhood vasculitis.

The Five-Factor Score revisited: assessment of prognoses of systemic necrotizing vasculitides based on the French Vasculitis Study Group (FVSG) cohort

The 1996 Five-Factor Score (FFS) for systemic necrotizing vasculitides (polyarteritis nodosa [PAN], microscopic polyangiitis [MPA], and Churg-Strauss syndrome [CSS]) is used to evaluate prognosis at diagnosis. In the current study we revisited the FFS, this time including Wegener granulomatosis (WG).We analyzed clinical, laboratory, and immunologic manifestations present at diagnosis of systemic necrotizing vasculitides for 1108 consecutive patients registered in the French Vasculitis Study Group database. All patients met the American College of Rheumatology and Chapel Hill nomenclature criteria. Univariable and multivariable analyses yielded the 2009 FFS for the 4 systemic necrotizing vasculitides.Overall mortality was 19.8% (219/1108); mortality for each of the SNV is listed in descending order: MPA (60/218, 27.5%), PAN (86/349, 24.6%), CSS (32/230, 13.9%), and WG (41/311, 13.2%) (p < 0.001). The following factors were significantly associated with higher 5-year mortality: age >65 years, cardiac symptoms, gastrointestinal involvement, and renal insufficiency (stabilized peak creatinine ≥150 μmol/L). All were disease-specific (p < 0.001); the presence of each was accorded +1 point. Ear, nose, and throat (ENT) symptoms, affecting patients with WG and CSS, were associated with a lower relative risk of death, and their absence was scored +1 point (p < 0.001). Only renal insufficiency was retained (not proteinuria or microscopic hematuria) as impinging on outcome. According to the 2009 FFS, 5-year mortality rates for scores of 0, 1, and ≥2 were 9%, 21% (p < 0.005), and 40% (p < 0.0001), respectively.The revised FFS for the 4 systemic necrotizing vasculitides now comprises 4 factors associated with poorer prognosis and 1 with better outcome. The retained items demonstrate that visceral involvement weighs heavily on outcome. The better WG prognosis for patients with ENT manifestations, even for patients with other visceral involvement, compared with the prognosis for those without ENT manifestations, probably reflects WG phenotype heterogeneity.

Recent aspects of vasculitis and future direction

Vasculitis is pathologically identified as specific cellular inflammation, vessel destruction, and tissue necrosis. Current classifications of vasculitis such as the Chapel Hill Classification (CHCC) and American College of Rheumatology (ACR) guidelines are not sufficiently adequate for clinicians to diagnose vasculitis. The biomarkers that are currently in clinical use such as PR3-ANCA and MPO-ANCA, only help in diagnosing small vessel vasculitis and their sensitivity and specificity are not sufficient. However, recent developments related to the pathogenesis and etiopathogenesis of vasculitis have the potential to contribute to new and improved biomarkers. The determination of diverse roles of ANCA and synergistic effects of infection, genetic, environmental factors and drugs on pathogenesis is quite important. The demonstration of a new autoantibody directed to hLAMP-2 and the resemblance to some microbial structures, in addition to the determination of the possible roles of hepatitis B and C on vasculitis are important findings. These hints may lead to new biomarker developments, providing a better method to diagnose vasculitis. The evidence on T cell immunity as circulatory and lesional will likely contribute to the development of new drugs for vasculitis.

T cells in ANCA-associated vasculitis: what can we learn from lesional versus circulating T cells?

Anti-neutrophil cytoplasmic antibody (ANCA) - associated vasculitis (AAV) is a life-threatening autoimmune disease characterized by an antibody-mediated glomerulonephritis and necrotizing vasculitis. Apart from antibodies, T cells are also involved in disease pathogenesis. This review stresses the hallmarks of T cell-mediated pathology in AAV and highlights the characteristics of lesional and circulating T cells in the immune response in AAV. Circulating effector T-cell populations are expanded and are in a persistent state of activation. Circulating regulatory T-cell subsets are less well characterized but seem to be impaired in function. Lesional effector T cells are present in granulomas, vasculitic lesions, and nephritis. Lesional T cells usually show pro-inflammatory properties and promote granuloma formation. Apart from T cells, dendritic cells are abundantly present at the sites of inflammation and locally orchestrate the immune response. Targeting the above-mentioned T cell-mediated disease mechanisms will potentially provide powerful therapeutic tools for AAV.

Granuloma formation in ANCA-associated vasculitides

Granuloma formation is a key pathologic finding in two of the anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides: Wegener's granulomatosis (WG) and Churg-Strauss syndrome (CSS). So far, no animal models have been established convincingly reproducing both vasculitic and granulomatous features typical of WG and CSS. In biopsies, granulomatous lesions are found both at distant extravascular sites and in the vicinity of inflamed vessels, e.g. in the lung. Intriguingly, WG-granulomata appear to display features of tertiary lymphoid tissue. Cartilaginous and osseous destruction is caused by granulomatous inflammation invading adjacent tissues. Rhinosinusitis is regularly encountered in WG and CSS. Septal perforation, saddle nose deformity, middle and inner ear symptoms, and granulomatous invasion of the palate, orbita, meninges, or the pituitary gland may complicate WG. Both common (e.g. FCGR3B copy number) and distinct (e.g. HLA-DP, IL-10.2) genetic factors have been identified in AAV potentially favouring inflammation and autoimmunity. The HLA-DPB1/RING1/RXRB region constitutes a quantitative trait locus for ANCA-positive WG with the strongest association to be reported up to now. A profound alteration of the T-cell response including Th1 and Th17 responses, anomalously NK-receptor-expressing 'NK-like' T cells, and dysfunctional regulatory T cells could facilitate and sustain granuloma formation and autoimmunity.

CD4-Positive Effector Memory T Cells Participate in Disease Expression in ANCA-Associated Vasculitis

Although the cause of ANCA-associated vasculitis (AAV) remains undetermined, the presence of lymphocytic infiltrates in inflammatory lesions of patients suggests that vascular damage is immune mediated. Studies over the past decade have implicated a role for T cells in the pathogenesis of AAV as altered T cell phenotype has been observed in this disorder. The distribution of T cell subpopulations has been analyzed most intensely in Wegener's granulomatosis (WG), where an expanded population of circulating CD4(+) effector memory T cells (CD4(+)T(EM)) was demonstrated. CD4(+)T(EM) cells play a major role in the pathogenesis of several autoimmune diseases. Specific suppression of CD4(+)T(EM) cells inhibits delayed-type hypersensitivity (DTH) and has therapeutic potential in autoimmune disease. Thus, CD4(+)T(EM) cells may act as inducers of tissue injury and participate in the development of AAV. Therapies that target CD4(+)T(EM), without impairing the activity of other lymphocyte subsets, may hold therapeutic promise for AAV.

Modification of lymphocyte subsets in patients with rhinoscleroma

PURPOSE

Rhinoscleroma is a rare, chronic, granulomatous disorder of the upper airways. This disease presents some etiopathogenetic aspects that are not yet clear. Infection by Klebsiella rhinoscleromatis is fundamental for the onset of the disease, but it is impossible to reproduce rhinoscleroma experimentally only via infection with the bacteria both in man and in animals. Furthermore, this disease mainly affects blood-related people and occurs in certain geographic areas. In this context, we present a study that brings to light some of the quantitative abnormalities of the lymphocyte subsets.

MATERIALS AND METHODS

The study group consisted of 5 patients with rhinoscleroma. The following parameters were studied for each patient: clinical manifestations, histologic examinations, number of leukocytes, lymphocytes, and lymphocyte subsets.

RESULTS

In all patients, we noted the following: There was a relative reduction of the CD4+ cells, an absolute increase of the CD8+ cells, and an inversion of the CD4+/CD8+ ratio. There was an absolute increase of the CD56+ cells and cytotoxic cells that coexpress CD8+CD56+ antigens. There was a relative reduction of the CD3+ cells, and the CD19+ cells tended to show an ambiguous behavioral pattern.

CONCLUSION

We believe that K. rhinoscleromatis does not play a major role in the etiopathogenesis of rhinoscleroma. However, we do believe that the anomalous behavior of the immune system can favor rhinoscleroma.

Characterization of the expanded T-cell populations in patients with Wegener's granulomatosis

OBJECTIVES

Wegener's granulomatosis (WG) is a chronic inflammatory disease characterized by granulomatosis inflammation, systemic vasculitis and glomerulonephritis. In patients, the peripheral T cells are characterized by mono/oligoclonal CD4+/CD8+ T-cell AV/BV receptor expansions, with aberrant expression of activation markers. This study was designed to characterize the phenotypic differences between the expanded and nonexpanded T-cell populations. Expression of markers for activation, costimulation and adhesion molecules was examined. As earlier studies have shown aberrant expression of CD28/CD152, we also analysed the expression of another costimulatory system, the tumour necrotic factor receptor (TNFR) superfamily proteins.

DESIGN

Fluorocrome-conjugated monoclonal antibodies and flow cytometry was used to analyse the expression of the different markers on the surface of the expanded and nonexpanded subsets of T cells.

SETTING

The Karolinska Hospital and Karolinska Institutet in Stockholm, Sweden.

SUBJECTS

Nine patients with WG (six men and three women) had 16 TCRAV/BV CD4+/CD8+ expanded populations that were characterized.

RESULTS

The expanded TCRA/BV CD4+ and CD8+ cells had lower percentages of cells expressing CD28 and higher of those expressing CD152 (CTLA-4). The expanded CD4+ population had more cells expressing HLA-DR, CD57 and CCR5 (CD195), whilst the expression of CD25 was present on fewer of the expanded cells. The expanded CD8+ population contained more cells expressing CD137 (4-1BB), CD137 (4-1BBL), CD30 (Ki-1), CD40 and CD134 (OX40).

CONCLUSIONS

There were marked differences in the phenotypes of expanded and nonexpanded T-cell populations.

Persistent expansion of CD4+ effector memory T cells in Wegener's granulomatosis

In order to test the hypothesis that Wegener's granulomatosis (WG) is associated with an ongoing immune effector response, even in remission, we examined the distribution of peripheral naive and memory T-lymphocytes in this disease, and analyzed the function-related phenotypes of the memory T-cell population. Peripheral blood mononuclear cells (PBMCs) were freshly isolated from WG-patients in remission (R-WG, n=40), active WG-patients (A-WG, n=17), and age-matched healthy controls (HCs, n=21). Expression of CD4, CD8, CD45RO, CCR7, interleukin (IL)-18Ralpha, ST2L, and FoxP3 were determined by four-color flow cytometric analysis. CD45RO and CCR7 were used for distinction between naive and memory T cells, IL-18Ralpha, ST2L, and FoxP3 for the assessment of Type1, Type2, and regulatory T-cells, respectively. In R-WG, the CD4+CD45RO+CCR7- effector memory T-cell subpopulation (TEM) was relatively increased, whereas the CD4+CD45RO-CCR7+ naive T-cell population (TNaive) was decreased as compared to HC. The distribution of naive and memory CD8+T cells did not differ between R-WG, A-WG, and HC, nor did CD4+CD45RO+CCR7+ central memory T cells (TCM). In contrast to HC, the percentage of CD4+TNaive cells in R-WG correlated negatively with age, whereas CD4+TEM cells showed a positive correlation. In R-WG, a skewing towards Type2 T cells was observed in CD4+TEM cells. No differences were detected in FoxP3+CD4+TEM cells between R-WG and A-WG, whereas the FoxP3-CD4+TEM cells were increased in R-WG and decreased in A-WG as compared to HC. Collectively, peripheral blood homeostasis of CD4+T cells is disturbed in R-WG with the persistent expansion of non-regulatory CD4+TEM cells. These cells might be involved in relapse and may constitute a target for therapy.

Is PR3-ANCA formation initiated in Wegener's granulomatosis lesions? Granulomas as potential lymphoid tissue maintaining autoantibody production

In Wegener's granulomatosis (WG), antiproteinase 3 (PR3) autoantibodies (PR3-ANCA) are crucial in the development of generalized vasculitis. Wegener's pathognomonic lesion, a granulomatous inflammation of the upper and lower respiratory tract, contains abundant lymphocytes and macrophages. Lymphocyte clusters in germinal center-like formation within the granulomatous lesion are frequently observed, which suggests antigen-driven B cell maturation. Wegener's autoantigen PR3, the target for autoreactive B and T cells, is expressed in granulomatous lesions. Disease progression in WG is accompanied by a profound generalized alteration of T cell differentiation with an increase of effector memory T cells (CD4(+)CD28(-)). The cytokine profile suggests an aberrant Th1-type response either to an environmental trigger and/or the autoantigen PR3 itself. Staphylococcus aureus, a risk factor for disease exacerbation, is widely present in the upper airways in WG. The Ig gene repertoire from WG lesions indicates a predominance of VH3+ B cells with affinity to PR3 as well as to the S. aureus B cell superantigen SPA. Hence, within the WG lesion, S. aureus might support the maturation of PR3-affinity B cells that enter a germinal center reaction in contact with PR3 and T cells and expand, leading to PR3-ANCA production. Thus, granulomatous lesions could represent a potential lymphoid tissue-maintaining autoantibody production rather than a simple, random leukocyte accumulation in WG.

Anti-neutrophil cytoplasm-associated glomerulonephritis

Wegener's granulomatosis, microscopic polyangiitis, and renal limited vasculitis are associated with circulating anti-neutrophil cytoplasm antibodies and are an important cause of rapidly progressive glomerulonephritis. This review gives an account of recent advances in the understanding of the pathogenesis underlying these conditions and how these may lead to future treatments. Consideration is given to recent clinical trials in the management of anti-neutrophil cytoplasm antibodies (ANCA)-associated vasculitides.

Off balance: T-cells in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides

There is substantial evidence that T-cells are off balance in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides. Genetic risk factors may influence shaping of the TCR repertoire and regulatory control of T-cells in predisposed individuals. T-cells are found in inflammatory lesions. Vigorous Th1-type responses are seen in Wegener's granulomatosis and microscopic angiitis, whereas a Th2-type response predominates in Churg-Strauss syndrome. Oligoclonality and shortened telomers indicate antigen-driven clonal expansion and replicative senescence of T-cells in ANCA-associated vasculitides. Potent CD28(-) Th1-type cells displaying an effector-memory/late differentiated, senescent phenotype are expanded in peripheral blood and are found in granulomatous lesions in Wegener's granulomatosis. Differences in proliferative peripheral blood T-cell responses to the autoantigens proteinase 3 (PR3)- and myeloperoxidase (MPO) have not consistently been detected between patients with ANCA-associated vasculitides and healthy controls in vitro. To recognize an autoantigen, break tolerance, and maintain autoimmune disease T- and B-cells require particular triggers and lymphoid structures. There is preliminary evidence of lymphoid-like structures and possible maturation of autoreactive PR3-ANCA-specific B-cells in granulomatous lesions in Wegener's granulomatosis. Alteration of the T-cell response and anomalous autoantigen-presentation in lymphoid-structures could facilitate development of autoimmune disease in ANCA-associated vasculitides.

ThePTPN22 620W allele is a risk factor for Wegener's granulomatosis

OBJECTIVE

Analyses of families with multiple autoimmune disorders have revealed a functional polymorphism, 620W, in the intracellular tyrosine phosphatase gene PTPN22 as a predisposing factor for type 1 diabetes, seropositive rheumatoid arthritis, systemic lupus erythematosus, and Hashimoto thyroiditis, and the presence of the PTPN22 protein appears to herald the development of autoantibodies in these disorders. This study therefore examined whether the functionally relevant PTPN22 polymorphism is associated with Wegener's granulomatosis (WG).

METHODS

A population-based study was performed for the PTPN22 polymorphism in 199 patients with WG and in 399 healthy individuals. The R620W variation was investigated by simple restriction fragment-length polymorphism analysis.

RESULTS

The PTPN22 620W allele frequency was significantly increased in antineutrophil cytoplasmic antibody (ANCA)-positive WG patients compared with healthy controls (P < 0.001). The association was particularly striking in patients with kidney, lung, eye, and peripheral nervous system involvement (i.e., those with generalized WG).

CONCLUSION

The PTPN22 620W allele appears to be involved in the pathogenesis of WG, and ANCA positivity seems to be the hallmark.

Limited versus severe Wegener's granulomatosis: baseline data on patients in the Wegener's granulomatosis etanercept trial

OBJECTIVE

To report baseline data on 180 patients with Wegener's granulomatosis (WG) enrolled in the WG Etanercept Trial (WGET), and to examine demographic and clinical differences between patients with limited disease and those with severe disease.

METHODS

Definitions of limited and severe disease were agreed upon by consensus of the investigators at a pretrial meeting and were incorporated into the protocol as a stratification criterion. These data were applied prospectively to the WGET patient cohort, based on clinical features and the intention to treat patients according to disease activity. Data related to disease onset, date of diagnosis, clinical features, antineutrophil cytoplasmic antibody assays, tissue biopsy findings, and other medical history were collected on a baseline medical history form. Physician-investigators from each center participated in the development of this form, and all were certified in its use prior to the start of the trial. Selected data on patients who were screened for the trial but were not enrolled were also collected.

RESULTS

Several significant differences between the limited and severe disease subsets were observed. Patients with limited disease were nearly a decade younger at disease onset compared with patients with severe disease. Thirty-three percent of patients with severe disease were women, compared with 58% of those with limited disease. Despite their younger age at symptom onset, patients with limited disease tended to have longer disease duration, a greater likelihood of experiencing exacerbation of previous disease following a period of remission, and a higher prevalence of destructive upper respiratory tract disorders at the time of enrollment (e.g., saddle-nose deformity). Patients with limited WG were less likely than those with severe disease to have antibodies to either proteinase 3 or myeloperoxidase. Patients with severe disease had a higher likelihood of previous thyroid disease, particularly either Graves' disease or Hashimoto thyroiditis, suggesting the possibility of different pathogenetic factors within these disease subsets. Other observed differences between these subsets, such as the greater frequency of alveolar hemorrhage in the severe disease group, were related to the a priori definitions of limited and severe disease.

CONCLUSION

There are significant differences between patients with limited WG and those with severe WG with regard to sex, age, the likelihood of recurrent disease, the risk of damage in certain organ systems, and, possibly, etiologic factors. These differences (and perhaps other differences that are currently unrecognized) in patient subsets may have implications for mechanisms of pathogenesis, prognosis, response to treatment, and the design of future clinical investigations.

Differences in CCR5 expression on peripheral blood CD4+CD28- T-cells and in granulomatous lesions between localized and generalized Wegener's granulomatosis

Wegener's granulomatosis (WG) is an autoimmune disease characterized by granulomatous lesions and a necrotizing vasculitis. Th1-type-cells lacking CD28 are expanded independent of age and immunosuppressive therapy in WG. To address their migratory properties of CD4(+)CD28(-) T-cells we studied the expression of the inducible inflammatory Th1-type chemokine receptor CCR5 in localized WG and generalized WG. Expansion of CD4(+)CD28(-) T-cells was more prominent in generalized WG compared to localized WG. In localized WG a larger fraction of CD4(+)CD28(-) T-cells displayed CCR5 expression compared to generalized WG. CCR5 expression was also higher in granulomatous lesions in localized WG. Higher levels of CCR5 expression on CD4(+)CD28(-) T-cells in localized WG may favor stronger CCR5-mediated recruitment of this T-cell subset into granulomatous lesions in localized WG. Expansion of Th-1-type CD4(+)CD28(-)CCR5(+) effector memory T-cells might contribute to disease progression and autoreactivity, either directly, by maintaining the inflammatory response, or as a result of bystander activation.