ECMO Support in Paraneoplastic Pemphigus With Respiratory Failure: A Case Report With Immune Cell Monitoring.

Paraneoplastic pemphigus (PNP) is a life-threatening autoimmune blistering disease with a mortality rate of 70%-90%, driven largely by respiratory complications such as bronchiolitis obliterans. Managing respiratory failure in these patients remains exceptionally difficult. We report a 33-year-old male with follicular dendritic cell sarcoma who developed severe PNP complicated by type II respiratory failure and obstructive bronchiolitis requiring veno-venous extracorporeal membrane oxygenation (ECMO) support. The patient's PNP skin lesions improved during a treatment course that included ECMO support, intravenous immunoglobulin (IVIG), immunosuppressants, hemodialysis, and plasma exchange. Serial immune cell subset monitoring showed a rising CD4/CD8 ratio (+94.8%) and Helper T cells (+33.8%), alongside declining NK cells (-48.2%), T lymphocytes (-17.7%), and Suppressor T cells (-31.6%). This case illustrates successful short-term management of severe PNP with respiratory failure through multidisciplinary care, including ECMO. Because multiple interventions were administered concurrently, improvement cannot be attributed to any single therapy. Serial immune-cell monitoring may help track treatment response in this setting.