HPRT1 and acute promyelocytic leukemia: A. phagocytophilum HZ was not handled in the laboratory during the p44 PCR and sequencing experiments; however, because these sequences were similar to those from A. phagocytophilum HZ from an HGA patient and cultured in the human promyelocytic leukemia cell line HL-60, human HPRT-specific PCR was performed with GL21 DNA.