Transfusion-transmitted anaplasmosis from leukoreduced red blood cells

Human granulocytic anaplasmosis (HGA) is a tick-borne rickettsial infectious disease. To date four cases of transfusion-transmitted anaplasmosis (TTA) have been described in the literature, and only one from leukoreduced red blood cells (RBCs).

A 64-year-old patient with acute gastrointestinal blood loss was admitted to the hospital and received 5 units of prestorage leukoreduced RBCs. He was stabilized and discharged. He developed headache, fever, and chills 2 days after discharge and was readmitted. On Day 5 of his second admission polymorphonuclear leukocytes containing morulae consistent with HGA were reported in the peripheral smear.

Samples from the recipient tested positive by polymerase chain reaction (PCR) for Anaplasma phagocytophilum, the causative agent of HGA and a segment from one of the five donors tested positive by both serology and PCR.

Leukoreduction theoretically reduces the risk of TTA but does not interdict all infections. TTA requires consideration in recipients of RBC transfusion with unexplained fever.