RTX-naive ITP-spleen samples, compared with those from a 20-patient control trauma cohort, contained the following nonspecific, ITP-evocative, white-pulp lesions: follicular helper T-cell (programmed death-1 and inducible T-cell COStimulator) expansion in reactive follicles (P=0.01 and 0.03, respectively) and regulatory T-cell (FOXP3) expansion in the T-cell zone (P=0.049).
Moreover, the frequencies of circulating CXCR5(+) CD4(+)TFH cells with inducible costimulator (ICOS)(high) or programmed death-1 (PD-1)(high) expression were notably higher in ITP with platelet-antibody-positive ( ITP (+) ) patients than in ITP with platelet-antibody-negative ( ITP (-) ) patients and HC, as were the serum IL-21 and IL-6 levels (significant).