Use of convalescent plasma in COVID‐19 patients with immunosuppression

In the absence of effective countermeasures, human convalescent plasma has been widely used to treat severe acute respiratory syndrome coronavirus 2, the causative agent of novel coronavirus disease 19 (COVID‐19), including among patients with innate or acquired immunosuppression. However, the association between COVID‐19‐associated mortality in patients with immunosuppression and therapeutic use of convalescent plasma is unknown. We review 75 reports, including one large matched‐control registry study of 143 COVID‐19 patients with hematological malignancies, and 51 case reports and 23 case series representing 238 COVID‐19 patients with immunosuppression. We review clinical features and treatment protocols of COVID‐19 patients with immunosuppression after treatment with human convalescent plasma. We also discuss the time course and clinical features of recovery. The available data from case reports and case series provide evidence suggesting a mortality benefit and rapid clinical improvement in patients with several forms of immunosuppression following COVID‐19 convalescent plasma transfusion. The utility of convalescent plasma or other forms of antibody therapy in immune‐deficient and immune‐suppressed patients with COVID‐19 warrants further investigation.