The current standard for diagnosing primary HCMV infection is the detection of HCMV immunoglobulin G (IgG) with or without HCMV immunoglobulin M (IgM) in an individual with previously undetectable HCMV IgG and IgM, known as seroconversion.2 The gene discussed is CD40LG; the disease is cytomegalovirus infection.