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Objective To assess circulating follicular helper T (Tfh)-like CD4+ T cells in patients with systemic lupus erythematosus (SLE) and determine their relationship to disease activity. Methods Blood samples from patients with SLE, as well as blood samples from patients with Behçet's disease (BD) and healthy individuals as controls, were analyzed. In all samples, circulating Tfh-like cells were enumerated by flow cytometry, using, as markers, expression of CXCR5, inducible T cell costimulator (ICOS), and programmed death 1 (PD-1) protein, as well as secretion of interleukin-21 (IL-21). The frequency of circulating Tfh-like cells was compared to that of circulating plasmablasts (CD19+IgD−CD38+). In addition, the possible association of circulating Tfh-like cells with the SLE Disease Activity Index (SLEDAI) was evaluated. Results The subset of circulating Tfh-like T cells, identified as CXCR5highICOShighPD-1high, was expanded in the blood of SLE patients compared to controls. Circulating Tfh-like cells were found to produce IL-21 and had lower expression of CCR7 as compared to that in circulating CXCR5high central memory T cells, thereby enabling their distinction. Expression of PD-1, but not ICOS or CXCR5, was significantly elevated in circulating Tfh-like cells from SLE patients compared to controls. PD-1 expression among CXCR5high circulating Tfh-like cells correlated with the SLEDAI, frequency of circulating plasmablasts, and anti-double-stranded DNA antibody positivity, but not with disease duration or past organ injury; rather, this cell profile appeared to be a reflection of current active disease. Conclusion Circulating Tfh-like cells are associated with disease activity in SLE, suggesting that their presence indicates abnormal homeostasis of T cell-B cell collaboration, with a causal relationship that is central to disease pathogenesis. These findings also suggest that circulating Tfh-like cells provide a surrogate for aberrant germinal center activity in SLE, and that their PD-1 expression offers a tool for measuring disease activity and monitoring the response to therapies. [ABSTRACT FROM AUTHOR]

Background Autoantibodies to ribosomal P proteins (anti-rib P) are specific serological markers for systemic lupus erythematosus ( SLE) and are associated with liver involvement in this disease. The similarity in autoimmune background between autoimmune hepatitis ( AIH) and SLE-associated hepatitis raises the possibility that anti-rib P antibodies might also have relevance in AIH. Aims To evaluate the frequency and clinical significance of anti-rib P antibodies in a large AIH cohort. Methods Sera obtained at diagnosis of 96 AIH patients and of 82 healthy controls were tested for IgG anti-ribosomal P protein by ELISA. All of the sera were also screened for other lupus-specific autoantibodies, three patients with the presence of anti-ds DNA ( n = 1) and anti-Sm ( n = 2) were excluded. Results Moderate to high titres (>40 U) of anti-rib P antibody were found in 9.7% (9/93) of the AIH patients and none of the controls ( P = 0.003). At presentation, AIH patients with and without anti-rib P antibodies had similar demographic/clinical features, including the frequency of cirrhosis (44.4 vs. 28.5%, P = 0.44), hepatic laboratorial findings ( P > 0.05). Importantly, at the final observation (follow-up period 10.2 ± 4.9 years), the AIH patients with anti-rib P had a significantly higher frequency of cirrhosis compared with the negative group (100 vs. 60%, P = 0.04). Conclusion The novel demonstration of anti-rib P in AIH patients without clinical or laboratory evidence of SLE suggests a common underlying mechanism targeting the liver in these two diseases. In addition, this antibody appears to predict the patients with worse AIH prognoses. [ABSTRACT FROM AUTHOR]