Journal of Blood & Lymph

Six Cases of Infectious Mononucleosis by Cytomegalovirus as Diagnosed by Multiplex Virus PCR Assay

Abstract

Nagao M, Yoshioka Y, Saito T, Tsunemine H, Ito K, Kodaka T, Tsuji G, Watanabe K, Shimizu N* and Takahashi T*

Infectious mononucleosis (IM) is mostly caused by Epstein-Barr virus (EBV) while IM by cytomegalovirus (CMV) is rather rare. In our retrospective clinical research with multiplex virus PCR analysis, we encountered 6 cases of CMV-IM and analyzed the clinical characteristics including diagnostic problems. The diagnosis of CMV-IM was made when the CMV genome was solely detected from the patient’s peripheral blood by multiplex virus PCR analysis. Then viral load was determined by quantitative PCR. Viral serological examinations were performed by a laboratory company as routine laboratory tests. Specific PCR signal for CMV genome was obtained by multiplex virus PCR in 6 patients, and blood CMV load ranged from 102 to 104 copies/mL. Clinical pictures and laboratory findings of these patients with CMV-IM were similar to those of EBV-IM in terms of fever, fatigue, morphology and number of atypical lymphocyte, and liver dysfunction. On serological examination, an IgM antibody against CMV was positive in all 6 patients; however, a VCA-IgM antibody against EBV was also positive in all patients examined, compromising serological differential diagnosis of IM. To make an exact diagnosis of CMV-IM, direct detection of the virus genome is important, and our multiplex virus PCR assay may be very useful in terms of quick performance and good specificity