Cytomegalovirus Glycoprotein B Groups in Human Immunodeficiency Virus–Infected Patients with Incident Retinitis

Cytomegalovirus (CMV) strains may be categorized into 4 different groups on the basis of glycoprotein B (gB) genotype. gB genotypes in CMV polymerase chain reaction (PCR)-positive samples from case patients who were diagnosed with retinitis during prospective follow-up were compared with genotypes in CMV PCR-positive samples from an equal number of retinitis-free matched control subjects. All patients were infected with human immunodeficiency virus (HIV) and CMV. Control subjects and their plasma samples were matched with case patients according to baseline CD4(+) T cell count, transfusion history, HIV risk factor, and follow-up time. CMV DNA was genotyped by restriction-enzyme digestion. Eighteen patients met our case definition. Approximately one-third of patients had gB genotype 1, and half had gB genotype 2. These rates were similar among case patients and control subjects and were similar by risk group. The CMV gB2 genotype is not a major determinant of retinitis pathogenicity but appears to be highly prevalent among HIV-infected patients.