GALT CD4+PD-1hi T follicular helper (Tfh) cells repopulate after anti-retroviral therapy

Human immunodeficiency virus (HIV) and simian (SIV) infections are characterized by dramatic alterations in the mucosal CD4 T cell compartment. Though viremia is effectively suppressed, peripheral numbers recover to near healthy levels after highly active anti-retroviral therapy (HAART), some of dysfunctional consequences HIV infection continue persist during therapy. We hypothesized that follicular helper (Tfh) deficiencies may play a role this process. Using macaque model we show SIV was associated with significant loss Tfh cells GALT drain mesentery lining gastrointestinal tract (GIT). Loss significantly correlated depletion overall memory compartment; most expressed CD95+CD28+ phenotype suggesting compartment likely drives infection. Continuous (cART) accompanied repopulation similar those uninfected animals. Repopulating displayed higher capacity produce IL-21 as compared infected animals cART fully restores functionally capable supporting GC reactions GALT.