Extrafollicular Plasmablasts Present in the Acute Phase of Infections Express High Levels of PD-L1 and Are Able to Limit T Cell Response.

During infections with protozoan parasites or some viruses, T cell immunosuppression is generated simultaneously with a high B cell activation. It has been described that, as well as producing antibodies, plasmablasts, the differentiation product of activated B cells, can condition the development of protective immunity in infections. Here, we show that, in infection, all the plasmablasts detected during the acute phase of the infection had higher surface expression of PD-L1 than other mononuclear cells.

Inhibitory Receptor Expression on T Cells as a Marker of Disease Activity and Target to Regulate Effector Cellular Responses in Rheumatoid Arthritis.

Objective: Inhibitory receptors are essential for the regulation of effector immune responses and may play critical roles in autoimmune diseases. We evaluated whether inhibitory receptor expression on T cells from patients with rheumatoid arthritis (RA) were correlated with immune activation, disease activity, and response to treatment, as well as whether inhibitory receptor-mediated pathways were functional.

Methods: Using flow cytometry, we performed extensive phenotypic and functional evaluation of CD4+ and CD8+ T cells from the blood and synovial fluid (SF) of RA patients ex vivo and after culture.