Relationship between human cytomegalovirus glycoprotein B genotype and serum alanine aminotransferase elevation in infants.

The glycoprotein B (gB) region of the human cytomegalovirus (HCMV) is a major envelope glycoprotein that is a principal target of neutralizing antibodies and is known to stimulate the immune response of cytotoxic T lymphocytes. HCMV is currently classified into four genotypes on the basis of the nucleotide sequence of the gB region. The presence of HCMV in patients under 3 years of age was determined by subjecting urine samples taken from the patients to polymerase chain reaction (PCR) analysis. Analysis by direct sequencing of the gB region was carried out in 90 cases. These cases were grouped into the gB genotype 1 and gB genotype 3. Of 28 cases with a peak serum alanine aminotransferase (ALT) level(> or =100 IU/l), the duration of observed serum ALT elevation in the gB genotype 1 patients (166.7+/-126.7 days [mean+/-S.D.] [19 cases]) was significantly longer than that in the gB genotype 3 patients (39.7+/-31.7 days [9 cases]) (p<0.01). In the 54 cases with a serum ALT level(> or =50 IU/l), similar tendency was seen (p<0.05). These findings suggest that when serum ALT elevation is confirmed in young children infected with HCMV, analysis of the gB region is helpful for prediction of the duration of serum ALT elevation in the early stage of infection.