CD79A and congenital T-cell immunodeficiency: Thus, while the production of IgA+ B cells is conserved even under conditions of severe T cell deficiency, under physiological conditions (i.e., in the presence of functional T cells), most IgA+ PC are highly mutated, T cell-dependent, and GC-derived in order to contribute to the regulation of the bacterial community [2, 3, 5, 23].