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

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.