Sequence analyses of variable cytomegalovirus genes for distinction between breast milk– and transfusion‐transmitted infections in very‐low‐birth‐weight infants

摘要

BACKGROUND Cytomegalovirus (CMV) transmission to very‐low‐birth‐weight infants (VLBWIs) sometimes induces serious clinical symptoms. Although breast milk is considered a major source of transmission, transfusion‐transmitted CMV (TT‐CMV) infection is often suspected when CMV disease develops after transfusion. Thus, it is clinically important to distinguish between transfusion‐transmitted and breast milk–transmitted CMV infections. STUDY DESIGN AND METHODS Study A: The incidence of acquired CMV transmission was prospectively investigated in 65 VLBWIs. Study B: To determine the transmission routes in 18 TT‐CMV–suspected VLBWIs who had been reported in our hemovigilance system, we performed polymerase chain reaction for CMV DNA in fed breast milk and/or repository blood samples related to transfused leukoreduced blood products. Furthermore, we evaluated the identity of CMV strains in patients' urine/blood samples and fed breast milk by sequence analyses of variable CMV genes UL139 and UL146 . RESULTS Study A: Acquired CMV infection was found in 4 of 65 VLBWIs (6.2%). Study B: CMV DNA was detected in fed breast milk for 12 of 14 TT‐CMV–suspected cases, for which breast milk was available. Furthermore, CMV DNA sequence‐matching rates between fed breast milk and patients' urine/blood for both UL139 and UL146 genes were 100% or nearly 100% in 11 patients. In contrast, repository blood samples for 11 of 14 patients were CMV DNA negative. CONCLUSION CMV is principally transmitted through breast milk in VLBWIs. The risk of TT‐CMV seems to be extremely low when using leukoreduced blood products. Sequence analyses of the variable CMV genes are useful for evaluating CMV transmission routes.