CD40LG and cytomegalovirus infection: The BM CMV‐DNA (+) rate was correlated with plasma CMV‐DNA (+), PBMC CMV‐DNA (+), urine CMV‐DNA (+), and serum CMV‐IgM (+) rates, indicating that the BM CMV‐DNA test is necessary for infants with negative blood or urine test results and a suspected CMV infection, which can guide the tracing and treatment of CMV infection‐associated diseases.23 We also evaluated the diagnostic performance of the four methods and determined that the best diagnostic performance for BM‐acquired CMV infection was achieved by the urine CMV‐DNA test, better by the PBMC CMV‐DNA test.