Distribution of Human Cytomegalovirus gB Genotypes and Its Association with Diseases in Hematopoietic Stem Cell Transplant Recipients in Korea; A Preliminary Report

Choi, Su Mi; Kim, Jin Hee; Lee, Dong Gun; Park, Sun Hee; Choi, Jung Hyun; Yoo, Jin Hong; Park, Chul Min; Lee, Jong Wook; Min, Woo Sung; Hwang, Eung Soo; Shin, Wan Shik; Kim, Chun Choo

Abstract

BACKGROUND: Human cytomegalovirus (HCMV) glycoprotein B (gB) is the major envelope glycoprotein, encoded by the UL55 gene. Based on sequence variation in the UL55 gene, HCMV can be classified into four gB genotypes. Previous studies have suggested an association between HCMV gB genotypes and clinical outcome in the immunocompromised hosts. The goal of this study was to determine the distribution of HCMV gB genotypes and the effect of gB genotype in the developement of HCMV diseases in hematopoietic stem cell transplant (HSCT) recipients in Korea.
MATERIALS AND METHODS
DNA was extracted from 94 blood specimen of 52 allogeneic HSCT recipients with HCMV infection. HCMV gB genotype was determined using polymerase chain reaction to amplify a region of UL55, followed by restriction fragment length polymorphism (RFLP) analysis based on RsaI and HinfI digestion.
RESULTS
The distribution of gB types were as follows: gB1, 73.1% (38/52) of patients; gB2, 13.5% (7/52); gB3, 1.9% (1/52) and mixed infection (gB1 and gB2), 9.6% (5/52). While gB4 was not detected, a new genotype (described as gB7 by Trincado et al, 2000) was identified on the basis of their RFLP pattern. During average 708 days' follow up period, HCMV diseases developed in 5 patients. All of them had gB1 genotype. There was no statistically significant association between the incidence of HCMV diseases and the gB genotypes. Re-infection with gB1 strain was detected in one patient who had been previously infected with gB2. This episode was associated with fever, elevated liver enzyme and positive antigenemia.
CONCLUSION
HCMV gB1 was the dominant genotype and no gB4 was detected in allogeneic HSCT recipients in Korea, which is an unique pattern compared with the previous reports. Although we can not find significant association between the HCMV diseases and the gB genotypes, genotyping of HCMV will serve in the study of pathogenesis and transmission of this virus in transplant patients. Further study is underway with large study population.