Mixed Cold and Warm Autoimmune Hemolytic Anemia Following Babesiosis in an Immunocompromised Patient

Babesiosis is a tick-borne infection diagnosed by characteristic intracellular inclusions on peripheral blood smears. While nonimmune hemolytic anemia is a known complication of babesiosis infection, autoimmune hemolytic anemia caused by babesiosis infection is much more rare. Here, we describe a case of cold agglutinin syndrome in a patient with babesiosis infection who was also on ofatumumab therapy for multiple sclerosis. The patient continued to have evidence of hemolysis after appropriate antimicrobial therapy and after clearance of peripheral blood smears. This case illustrates a need for further research into CAS associated with babesiosis infection.