Facilitated expansion of Th17 cells in lupus nephritis patients.

The objective of this study was to investigate the mechanisms of T helper type 17 (Th17) expansion in lupus nephritis (LN) patients, and to determine whether or not it is associated with impaired function of regulatory T cells (Treg ). Major effector subsets of peripheral blood CD4+ T cells were assessed by flow cytometry in 33 LN patients with different activity of the disease and 19 healthy controls. The percentage of circulating Th17 cells was increased in LN (median = 1·2% of CD4+ compared to 0·6% in the control group, P < 0·01), while Treg cells remained unchanged (12·3 versus 12·1% in controls), resulting in a significantly lower Treg /Th17 ratio. Th17 expansion in the patient group was not related to LN activity, renal histology or blood and urine inflammatory biomarkers, but has been associated with a higher cumulative dose of cyclophosphamide. Treg cells in LN displayed mainly effector memory phenotype and expressed higher levels of transforming growth factor (TGF)-ß; however, their suppressant activity in lymphocyte proliferation assay was diminished compared to controls (~fourfold, P < 0·05). Co-culture of Treg and conventional CD4+ T cells resulted in marked suppression of the Th1 subset in both of the groups studied, but also in a potent expansion of Th17 cells, which in LN was twofold higher, as in controls (P < 0·05). In conclusion, our results demonstrate that Th17 expansion in LN is not increased during disease exacerbation, but is related to chronic immunosuppressive therapy. This immune signature is probably linked to the abnormal function of Treg cells, which were less suppressive in LN patients and even facilitated differentiation of Th17 cells.

Urinary cytokines and mRNA expression as biomarkers of disease activity in lupus nephritis.

Introduction Renal involvement is one of the most serious manifestations of systemic lupus erythematosus, but non-invasive assessment of inflammatory response in kidneys is challenging. In this study we aimed to validate markers of active lupus nephritis (LN) using urine immune profiling. Methods Urine and serum cytokines (17-plex array) and urine mRNA expression (∼40 immune and glomerular injury genes) were measured in LN patients with active disease ( n = 17) during remission ( n = 16) and in healthy subjects ( n = 18). Results Urine and serum levels of CCL2, CCL5 and CXCL10 were elevated in active LN as compared with disease remission (best discrimination for urine CXCL10 and CCL2) and correlated with LN activity. In the active disease, urinary cell transcriptome showed marked upregulation of proinflammatory cytokines (e.g. TNF, CCL2, CCL5, CXCL10), and type-1 immunity-related genes (e.g. CD3G, CD4, TBX21, IFNG). An active pattern of gene expression was also observed in four patients in remission, who had moderately increased urinary leucocyte count. Two patients from this group developed renal exacerbation during the following 3 months. Markers of type-17 immune axis (e.g. IL-17A) were not significantly increased in active LN. Conclusions Active LN patients were characterized by marked increase of proinflammatory mediators in the urine. Urine cytokines (CCL2 and CXCL10) and type-1 T-cell-related gene markers in the urine sediment had similar diagnostic performance in detection of active LN.

Signs of impaired immunoregulation and enhanced effector T-cell responses in the primary antiphospholipid syndrome.

INTRODUCTION: We investigated whether primary antiphospholipid syndrome (PAPS) is characterized by a deficiency in immunoregulatory pathways, a phenomenon recently implicated in the pathogenesis of autoimmune diseases. METHODS: Serum levels of immunoregulatory (e.g., IL-10 and TGF-ß1) and proinflammatory (e.g., IL-17A) cytokines were measured in PAPS, systemic lupus erythematosus (SLE) with secondary APS (SAPS), or without APS, and in healthy controls (n = 40 in each group). In a subgroup of PAPS patients we also compared phenotype and function (flow cytometry) of regulatory T-cells (Treg) and cytokine production by effector T-cells. RESULTS: Our major finding was decreased levels of TGF-ß1 in PAPS and SAPS as compared to SLE without APS and controls. TGF-ß1 was the lowest in PAPS patients showing high levels of aPL IgG with significant negative correlation with the titer. SLE patients were characterized by lower serum levels of IL-2 and increased IL-17A, as compared to the other groups. The numbers of circulating Treg cells and their phenotype (e.g., FoxP3 isoforms) were not disturbed in PAPS. However, surface expression of latency associated peptide (binds TGF-ß) in activated FoxP3 + cells and in vitro production of TGF-ß1 were decreased in PAPS patients with high titers of aPL IgG. Moreover, frequencies of cytokine producing effector T-helper cells (including Th17) were significantly elevated in this group. CONCLUSIONS: PAPS patients with high titers of aPL IgG antibodies were characterized by decreased systemic levels of TGF-ß1 and its impaired production in vitro, suggesting impaired immunoregulation and enhanced adaptive autoimmune responses leading to the production of aPL antibodies.