Autoimmune Hemolytic Anemia Associated With Human Babesiosis

Babesiosis is characterized by non-autoimmune hemolytic anemia as a result of invasion of red blood cells by intraerythrocytic protozoans. Upon evaluation of patients who have ongoing hemolysis despite antibiotic treatment, a new entity of autoimmune hemolytic anemia (AIHA) was recently identified in some patients with babesiosis. The data are limited to case reports and one case series. The aim of this research was to synthetize data on this topic according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the PubMed database. In this review, we found that all patients who had developed AIHA were asplenic. All had Coombs test positive for IgG or both IgG and C3 indicating Warm AIHA. Some but not all required blood transfusion and plasma exchange. Majority of patients responded to steroids and had resolution of parasitemia on follow-up. We believe that this review will make the clinicians aware that babesiosis can not only cause non-immune hemolysis but also AIHA. It is important to differentiate between the two entities as antibiotics alone may not be sufficient for immune-mediated hemolysis caused by babesiosis.