Mucosal-associated invariant T cells are depleted and functionally altered in patients with common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunoglobulin deficiency characterized by recurrent infections and complications, including autoimmunity, enteropathy, polyclonal lymphocytic infiltration or lymphoid malignancy. Innate T cells can support B cell maturation and antibody production. We investigated the numbers, phenotypes and functions of circulating B cell,.gamma delta T cell, invariant natural killer T (iNKT) cell and mucosal-associated invariant T (MAIT) cell subsets in 23 CVID patients and 27 healthy controls. Switched memory B cells and plasmablasts were depleted in CVID patients (p < 0.0001).gamma delta T cells were found at normal numbers, but iNKT and MALT cells were depleted (p < 0.0001 and p < 0.002). MAIT cells were especially low in patients with complicated CVID (p < 0.05). MAIT cells from patients appeared more activated and more frequently produced interleulcin-17A, interleukin-22 and tumor necrosis factor-alpha than MALT cells from healthy subjects in vitro. Thus, MAIT cell depletion and activation may contribute to immunodeficiency and complications associated with CVID. (C) 2016 Elsevier Inc. All rights reserved.