A splenic IgM memory subset with antibacterial specificities is sustained from persistent mucosal responses.

To what extent immune responses against the gut flora are compartmentalized within mucosal tissues in homeostatic conditions remains a much-debated issue. We describe here, based on an inducible AID fate-mapping mouse model, that systemic memory B cell subsets, including mainly IgM B cells in spleen, together with IgA plasma cells in spleen and bone marrow, are generated in mice in the absence of deliberate immunization. While the IgA component appears dependent on the gut flora, IgM memory B cells are still generated in germ-free mice, albeit to a reduced extent.

BAFF and CD4 T cells are major survival factors for long-lived splenic plasma cells in a B-cell-depletion context.

Previous data have suggested that B-cell-depletion therapy may induce the settlement of autoreactive long-lived plasma cells (LLPCs) in the spleen of patients with autoimmune cytopenia. To investigate this process, we used the AID-CreERT2-EYFP mouse model to follow plasma cells (PCs) engaged in an immune response. Multiplex polymerase chain reaction at the single-cell level revealed that only a small fraction of splenic PCs had a long-lived signature, whereas PCs present after anti-CD20 antibody treatment appeared more mature, similar to bone marrow PCs.

Long-term complications of splenectomy in adult immune thrombocytopenia.

The recent large decrease in splenectomy use for chronic immune thrombocytopenia (ITP) is partly due to still-unsolved questions about long-term safety. We performed the first single-center exposed/unexposed cohort study evaluating the long-term incidence of splenectomy complications in patients with primary ITP. Overall, 83 patients who underwent splenectomy more than 10 years ago (exposed) were matched with 83 nonsplenectomized patients (unexposed) on the date of ITP diagnosis ±5 years, age and gender.

Kikuchi Disease-Like Inflammatory Pattern in Cutaneous Inflammatory Infiltrates Without Lymph Node Involvement: A New Clue for the Diagnosis of Lupus?

Kikuchi-Fujimoto disease (KFD) is a rare and benign disorder that usually occurs in young adults with enlarged lymph nodes containing infiltrate of cytotoxic T cells and nuclear debris. It can be a manifestation of systemic lupus erythematosus (SLE) although the strength of this association has varied among studies. Although specific KFD cutaneous lesions are well described, pure cutaneous lesions have never been reported.

Are anti-proteinase-3 ANCA a useful marker of granulomatosis with polyangiitis (Wegener's) relapses? Results of a retrospective study on 126 patients.

Objectives: Predicting granulomatosis with polyangiitis (Wegener's) (GPA) relapses based on ANCA titers remains a source of debate. Our objective was to evaluate the relevance of monitoring PR3-ANCA titers for GPA management.

Methods: This retrospective study included 126 patients fulfilling the 1990 ACR criteria for GPA and PR3-ANCA-positive at the time of diagnosis.