Acute autoimmune hemolytic anemia due to anti‐En^a autoantibody successfully treated with rituximab

Abstract

BACKGROUND Autoimmune hemolytic anemia (AIHA) due to anti‐Ena has been previously reported in association with massive intravascular hemolysis, disseminated intravascular coagulation, and fatal outcomes. Here we report a case of successfully treated AIHA due to anti‐Ena. CASE REPORT A 69‐year‐old male with a past medical history of cirrhosis due to nonalcoholic steatohepatitis status post–orthotopic liver transplant presented with 1‐month history of progressive anemia. At presentation, his hemoglobin (Hb) was 5.6 g/dL, hematocrit (Hct) 16%, reticulocytes 0.3%, direct bilirubin (bili) 4 g/dL, lactate dehydrogenase 533 units/L (reference, 125‐220 units/L), and haptoglobin 254 mg/dL (reference, 40‐273 mg/dL). Blood bank testing revealed an autoantibody present in his plasma and a direct antiglobulin test positive for immunoglobulin G (IgC) but negative for complement. He received 1 unit of an incompatible blood group O phenotypically matched red blood cell unit. RESULTS Over the course of the next 5 days, the Hb and Hct decreased to 4.1 g/dL and 12%, respectively, direct bili increased to 12.3 mg/day, reticulocytes slightly increased to 0.9%, and haptoglobin decreased to less than 8 mg/dL. Marrow study showed a hypercellular marrow with erythroid hyperplasia. Additional workup performed at a reference laboratory identified an anti‐Ena autoantibody. He received prednisone and weekly rituximab infusions and was monitored weekly. At the 2‐month visit, Hb and Hct were 10 g/dL and 32%, respectively. CONCLUSION Unlike two of the previously reported fatal cases of AIHA with anti‐Ena specificity, this 69‐year‐old male treated with weekly rituximab infusion underwent clinical recovery and significant anemia improvement.

Red Cell Antibodies Against High Frequency Antigens, A Two Year Experience At A Regional Transfusion Institute

“…In the previous literature, there was a case report of AIHA due to anti Ena, which was treated successfully. 16 Anti Wr b was first described in a Wr (a+ b-) subjects. The antibody has been found as a separable specificity, together with "anti Ena", in the serum of En (a-) subjects who were also Wr (a-b-).…”