Use of sutimlimab to manage anemia in a patient with high‐grade B ‐cell lymphoma and complement binding anti‐ AnWj autoantibody

BACKGROUND: Anti-AnWj autoantibody production with concomitant antigen suppression rarely has been reported secondary to lymphoid malignancy. Anti-AnWj autoantibodies are often considered clinically insignificant; however, cases of posttransfusion hemolysis have been documented which require transfusion of AnWj-negative red blood cells (RBC). AnWj-negative RBC units are rare, thus options for long-term transfusion are limited. We report the novel use of sutimlimab, a classical complement pathway inhibitor, for severe anemia in a patient with a complement fixing anti-AnWj autoantibody. CASE PRESENTATION: A 57-year-old male with high-grade B-cell lymphoma presented with severe anemia and was found to have an anti-AnWj autoantibody of IgM and IgG isotypes and a complement-positive direct antiglobulin test. AnWj-positive RBC were provided for transfusion. His hemoglobin did not augment, and he developed evidence of hemolysis following crossmatch-incompatible RBC units. Transfusion of In(Lu) RBC showed initial response; however, his anemia persisted. Sutimlimab was subsequently initiated based on the complement fixing ability of the autoantibody. An improvement in hemoglobin, decrease in lactate dehydrogenase, and decrease in RBC-bound complement fragments were observed following sutimlimab administration. CONCLUSION: Management strategies for clinically significant anti-AnWJ are not well defined. To our knowledge, this is the first case using sutimlimab to manage complement-mediated hemolysis due to an auto-anti-AnWj antibody. While initial response to sutimlimab was favorable, the patient's comorbid lymphoma, multiple therapies, and short treatment period limit definitive conclusions regarding efficacy. Anti-complement therapy warrants further study for refractory antibody-mediated hemolysis with evidence of complement activation in the absence of compatible transfusions.