Circulating immune profile in granulomatosis with polyangiitis reveals distinct patterns related to disease activity.

Granulomatosis with polyangiitis (GPA) is an autoimmune disorder characterized by recurrent relapses that can cause severe tissue damage and life-threatening organ dysfunction. Multiple immune cells and cytokines/chemokines are involved in the different stages of the disease. Immune profiling of patients may be useful for tracking disease activity, however, reliable immune signatures for GPA activity are lacking. In this study, we examined circulating immune profiles in GPA patients during active and remission disease states to identify potential immune patterns associated with disease activity. The distribution and phenotypic characteristics of major circulating immune cells, and the profiles of circulating cytokines/chemokines, were studied on cryopreserved peripheral blood mononuclear cells from GPA patients (active, n = 20; remission, n = 20) and healthy controls (n = 20) leveraging a 40-color optimized multicolor immunofluorescence panel (OMIP-69) and in serum using a 46-plex Luminex multiplex assay, respectively. Deep phenotyping uncovered a distinct composition of major circulating immune cells in active GPA and GPA in remission, with the most significant findings emerging within the monocyte compartment. Our detailed analysis revealed circulating monocyte diversity beyond the conventional monocyte subsets. We identified eight classical monocyte populations, two intermediate monocyte populations, and one non-classical monocyte population. Notably, active GPA had a higher frequency of CD45RA+CCR5+CCR6-CCR7+/lowCD127-HLA-DR+CD2- classical monocytes and a lower frequency of CD45RA-CCR5-/lowCCR6-CCR7-CD127-HLA-DR+CD2+/- classical monocytes, which both strongly correlated with disease activity. Furthermore, serum levels of CXCL1, CXCL2, and CCL20, all linked to monocyte biology, were elevated in active GPA and correlated strongly with disease activity. These findings shed light on the circulating immune profile of GPA and may lead to immune signature profiles for assessing disease activity. Monocytes in particular may be studied further as potential markers for monitoring GPA.

Pathogenesis of antineutrophil cytoplasmic autoantibody-associated vasculitis and potential targets for biologic treatment.

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides (AAV) are autoimmune diseases in which the small vessels are inflamed. Clinical observations suggest a pathogenic role for ANCA. Such a role is supported by in vitro experimental data and animal models, particularly for myeloperoxidase-ANCA. An in vivo pathogenic role of ANCA directed to proteinase 3 has, however, not been fully substantiated. Additionally, the pathogenic role of B cells, T cells, and the alternative pathway of complement in AAV have been elucidated. Insight into these pathogenic pathways involved in AAV has opened and will further open new ways for targeted biologic treatment. In this review the pathogenesis of AAV and potential targets for biologic treatment are discussed.

Characterization of urinary CD4⁺ and CD8⁺ T cells in kidney transplantation patients with polyomavirus BK infection and allograft rejection.

BACKGROUND AND OBJECTIVES: The objective of this study was to characterize CD4(+) and CD8(+) T-cell populations in blood and urine of renal transplant patients with BK virus (BKV) infection or allograft rejection. MATERIALS AND METHODS: Percentages and absolute numbers of CD4(+) and CD8(+) effector memory T-cell subtype (TEM ) and terminal differentiated T cells (TTD ) in renal transplant patients with BKV infection (n = 14), with an episode of allograft rejection (n = 9), and in uncomplicated renal transplant patients with a stable kidney function (n = 12) were measured and compared using 4-color fluorescence-activated cell sorting. Results were correlated with the number of CD4(+) and CD8(+) T cells in renal biopsies. RESULTS: In patients with allograft rejection, the number of urinary CD4(+) TEM and CD8(+) TEM cells was significantly increased compared to patients with BKV infection or patients without complications. Positive correlation was found between the number of CD4(+) and CD8(+) cells in the renal biopsies and the number of CD4(+) and CD8(+) cells in urine. In patients with rejection, after 2 months of immunosuppressive therapy, a reduction in urinary CD8(+) TEM cells was found. CONCLUSIONS: CD4(+) TEM and CD8(+) TEM cells in urine could be a marker to distinguish allograft rejection from BKV-associated nephropathy and to monitor therapy effectiveness in renal transplant patients with allograft rejection.

Are urinary levels of high mobility group box 1 markers of active nephritis in anti-neutrophil cytoplasmic antibody-associated vasculitis?

The objective of this study is to evaluate urinary high mobility group box 1 (HMGB1) levels as markers for active nephritis in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in comparison with urinary CD4(+) effector memory T cells and urinary monocyte chemoattractant protein-1 (MCP-1). Twenty-four AAV patients with active nephritis and 12 healthy controls (HC) were evaluated. In nine patients, samples were also obtained during remission. Urinary levels of HMGB1 were measured by Western blot. CD4(+) T cells and CD4(+) effector memory T cells (CD4(+) CD45RO(+) CCR7(-) ) were determined in urine and whole blood by flow cytometry. Measurement of urinary levels of MCP-1 and serum HMGB1 levels were performed by enzyme-linked immunosorbent assay (ELISA). AAV patients with active nephritis had higher median intensity of HMGB1 in urine than HC [10·3 (7·05-18·50) versus 5·8 (4·48-7·01); P = 0·004]. Both urinary HMGB1 and MCP-1 levels decreased significantly from active nephritis to remission. The urinary MCP-1/creatinine ratio correlated with Birmingham Vasculitis Activity Score (BVAS) (P = 0·042). No correlation was found between the HMGB1/creatinine ratio and 24-h proteinuria, estimated glomerular filtration rate (eGFR), MCP-1/creatinine ratio, BVAS and serum HMGB1. A positive correlation was found between urinary HMGB1/creatinine ratio and CD4(+) T cells/creatinine ratio (P = 0·028) and effector memory T cells/creatinine ratio (P = 0·039) in urine. Urinary HMGB1 levels are increased in AAV patients with active nephritis when compared with HC and patients in remission, and urinary HMGB1 levels are associated with CD4(+) T cells and CD4(+) effector memory T cells in urine. Measurement of urinary HMGB1 may be of additional value in identifying active glomerulonephritis in AAV patients.

Abatacept treatment reduces disease activity in early primary Sjögren's syndrome (open-label proof of concept ASAP study).

OBJECTIVE: To assess the efficacy and safety of abatacept in patients with early and active primary Sjögren's syndrome (pSS). METHODS: All 15 patients (12 women, three men) included in the open-label Active Sjögren Abatacept Pilot study met the revised American-European Consensus Group criteria for pSS and were biological disease-modifying antirheumatic drug-naive. Patients were treated with eight intravenous abatacept infusions on days 1, 15 and 29 and every 4 weeks thereafter. Follow-up was conducted at 4, 12, 24 (on treatment), 36 and 48 weeks (off treatment). Disease activity was assessed with European League Against Rheumatism (EULAR) Sjögren's Syndrome Disease Activity Index (ESSDAI) and EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI). Several other functional, laboratory and subjective variables were analysed. Generalised estimating equations were used to analyse parameters over time. RESULTS: ESSDAI, ESSPRI, rheumatoid factor and IgG levels decreased significantly during abatacept treatment and increased post-treatment. Salivary and lacrimal gland function did not change during treatment. Fatigue and health-related quality of life (HR-QoL) improved significantly during treatment. No serious side effects or infections were seen. CONCLUSIONS: In this open-label study, abatacept treatment is effective, safe and well tolerated, and results in improved disease activity, laboratory parameters, fatigue and HR-QoL in patients with early and active pSS. TRIAL REGISTRATION NUMBER: 2009-015558-40.

Regulators of B-cell activity in SLE: a better target for treatment than B-cell depletion?

B cells, being a source of characteristic antinuclear autoantibodies, play a crucial role in the pathogenesis of systemic lupus erythematosus (SLE). Evidences indicate that alterations in B-cell regulation are responsible for B-cell hyperactivity as seen in SLE. T cells, soluble factors, and even B cells themselves regulate effector B-cell functions. The latter, so-called regulatory B cells possess regulatory function through production of the cytokine interleukin-10 (IL-10) that can damp down the humoral immune responses. This review will focus on B-cell regulation in the pathogenesis of SLE as a target for intervention. In particular, the regulatory impact of T cells through costimulation, soluble factors such as B lymphocyte stimulator, and the characteristics of IL 10-producing regulatory B cells will be discussed. Therapies targeting B cells as well as B-cell regulation seem promising, but the precise mechanisms involved in these interventions are not completely understood. More insight into B-cell regulation in SLE, and particularly in regulatory B cells, could lead to novel therapeutic strategies.

Staphylococcal toxic-shock-syndrome-toxin-1 as a risk factor for disease relapse in Wegener's granulomatosis.

OBJECTIVES: Nasal carriage of Staphylococcus aureus constitutes a risk factor for disease exacerbation in Wegener's granulomatosis (WG). We hypothesized that staphylococcal superantigens (SAg) are a determinant of S. aureus-related risk for disease relapse in WG. METHODS: In a retrospective longitudinal cohort study in 62 WG patients, we investigated the presence of the staphylococcal SAg genes sea, seb, sec, sed, see, tsst-1 and eta in S. aureus strains isolated from WG patients during an observation period of seven years. Subsequently, we assessed whether relapses of WG were associated with the presence of SAg-positive staphylococci. RESULTS: Of 1718 swab cultures analysed, 709 (41.2%) were S. aureus-positive. Fifty-one patients carried S. aureus, of whom 37 (72.5%) patients carried at least one SAg-positive S. aureus strain. Of the 709 S. aureus-positive cultures, 326 (46%) contained at least one SAg gene. Except for see, all assessed SAg genes were detected. sea was found most frequently, followed by sec, tsst-1 and eta and finally, by sed and seb. Using a multivariate, time-dependent Cox regression analysis we found that the presence of S. aureus was associated with relapses of WG (RR 3.2; 95% CI 1.2-8.4). The risk for relapse was modulated by the presence and type of SAg, with tsst-1 being associated with an increased risk for relapse (RR 13.3, 95% CI 4.2-42.6). CONCLUSION: The risk for relapse of WG increases with the presence of tsst-1-positive S. aureus. Eradication of tsst-1-positive S. aureus in WG may show whether disease relapses can be prevented.

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.