S4912 Infliximab-Induced Warm Autoimmune Hemolytic Anemia in a Patient With Ulcerative Colitis

Introduction: Autoimmune hemolytic anemia (AIHA) occurs when antibodies form against erythrocyte surface antigens leading to an increased destruction of red blood cells. There are multiple kinds of AIHA including warm antibody type, cold agglutinin, secondary cold agglutinin, and paroxysmal cold hemoglobinuria. In warm AIHA (w-AIHA), antibodies have the highest affinity for antigens at 37 degrees celsius (body temperature) and thus the most common type affecting 1 to 3 per 100,000. wAIHA can be further subdivided into primary and secondary. The cause of primary disease is usually unknown, but secondary can occur from causes such as medications, systemic lupus erythematosus, lymphoma, or infections. This case focuses on a patient with ulcerative colitis who developed warm autoimmune hemolytic anemia from the biologic medication infliximab. Case Description/Methods: A 25-year-old man with ulcerative colitis that was unresponsive to mesalamine on infliximab came in with complaints dyspnea for 1 week. He reported yellowing of his eyes, fatigue, and pale skin. The onset of symptoms correlated with his most recent infusion. He was found to have a hemoglobin of 5.6, WBC 19.3, AST 172, and a total bilirubin of 4.1 and was sent to the hospital. Upon admission, he received a transfusion of 3 units of packed red blood cells and computed tomography of the abdomen and pelvis was negative for any signs of acute gastrointestinal bleeding. Further workup revealed a lactate dehydrogenase of 2,911 and a positive Coombs test with antibody screen identifying warm autoantibodies. He was initiated on steroids 1 mg/kg/day and folic acid. His hemoglobin remained stable after initiation of treatment and he was discharged on oral prednisone with instructions to follow-up with hematology and gastroenterology. Discussion: Although rare, autoimmune hemolytic anemia is a serious side effect to be aware of in patients on biologics such as infliximab. This is especially true for patients with ulcerative colitis as it can also be an extraintestinal manifestation of the underlying inflammatory bowel disease. As in our patient’s case, not everyone responds well to first line mesalamine and biologics become their next best chance at getting into remission. Close monitoring should be imperative when infliximab is initiated in these patients. Once AIHA is suspected, the treatment should be held and other options explored. This was further evidenced in our patient by his quick resolution of symptoms and lab values upon discontinuing the medication.