Absence of Anti-Babesia microti antibody in commercial intravenous immunoglobulin (IVIG)

Babesiosis is a worldwide emerging protozoan infection that is associated with a spectrum of disease severity from asymptomatic infection to severe organ damage and death. While effective treatment strategies are available, some immunocompromised patients experience severe acute and prolonged/relapsing illness due in part to an impaired host antibody response. Intravenous immunoglobulin (IVIG) has been used as an adjunctive therapy in some immunocompromised babesiosis patients, but its therapeutic effect is uncertain. We evaluated the presence of Babesia microti antibodies in commercial samples of IVIG. The presence of B. microti antibodies in commercial samples of IVIG were tested using an immunofluorescence assay. A subset of samples was then tested for B. microti antibodies using an enzyme linked immunosorbent assay. Out of 57 commercial IVIG samples tested using IFA, and 52 samples tested using ELISA, none were positive for B. microti antibodies. Commercially available IVIG may not be of therapeutic benefit for babesiosis patients. Additional sampling of IVIG for B. microti antibody and a clinical trial of babesiosis patients given IVIG compared with controls would provide further insight into the use of IVIG for the treatment of babesiosis.