A case of transfusion-transmission Anaplasma phagocytophilum from leukoreduced red blood cells.

Background: Anaplasma phagocytophilum is a tick-borne bacterium and the cause of human granulocytic anaplasmosis (HGA). Here, we report a case of transfusion-transmitted (TT)-HGA involving a leukoreduced (LR) red blood cell (RBC) unit.

Case Report: A 64-year-old woman with gastric adenocarcinoma and multiple myeloma who received weekly blood transfusions developed persistent fevers, hypotension, and shortness of breath 1 week after receiving an RBC transfusion. Persistent fevers, new thrombocytopenia, and transaminitis suggested a tick-borne infection.

Results: The absence of blood parasites on thick and thin blood smears suggested that malaria and Babesia infection were not present, and the recipient tested negative for antibodies to Borrelia burgdorferi. Blood testing by polymerase chain reaction (PCR) for Ehrlichia and Anaplasma species identified A. phagocytophilum. Treatment with doxycycline resolved the infection; however, the recipient expired due to complications of her known malignancies. The recipient lived in a nursing home and did not have pets or spend time outdoors. The donor was a female in her 70s from Maine who was diagnosed with HGA 3 weeks after donating blood and whose LR-RBCs from the donation were transfused to the recipient 9 days following collection.

Conclusion: This is a confirmed case of TT-HGA. Although rare, TT-HGA has been reported with LR-RBCs and platelets. In endemic areas, testing for tick-borne associated infections should be considered when investigating post-transfusion complications.