CD4+ T Cells Predict Relapse in Pemphigus Vulgaris Treated With Rituximab: A Retrospective Study

ABSTRACT Objective This study evaluated the CD4 + T‐cell role in mediating post‐Rituximab Pemphigus vulgaris (PV) relapse, comparing CD4 + count and CD4 + /CD20 + ratio between patients who achieved remission and those who relapsed. Methods The clinical course of 27 PV patients treated with Rituximab was evaluated after a 32‐month median follow‐up. CD4 + and CD20 + counts and CD4 + /CD20 + ratio were longitudinally collected at treatment start date (T0), at 2‐month intervals after Rituximab, until B‐cell repopulation, at B‐cell repopulation, at 6‐, 12‐, and 24‐month intervals after repopulation, and at the end of follow‐up or at relapse. Results Patients were administered Rituximab as adjuvant therapy: 16 (59%) relapsed while 11 (41%) achieved clinical remission. Higher CD4 + count ( p = 0.02*) and CD4 + /CD20 + ratio ( p = 0.004**) were found at B‐cell repopulation in patients experiencing remission. Moreover, a significant difference ( p = 0.002**) in post‐repopulation CD4 + T‐cell course was found between groups, with patients in clinical remission reporting a mean decrease of 233.5 cells/μL during follow‐up and relapsing patients experiencing a mean increase of 539.4 cells/μL and reaching the maximum CD4 + value at relapse. Conclusions Lower CD4 + T‐cell value at repopulation and increasing post‐repopulation CD4 + T‐cell count were predictive of disease relapse suggesting a time‐dependent role of CD4 + T cells in post‐Rituximab PV reactivation.