Cytomegalovirus glycoprotein B genotyping in ocular fluids and blood of AIDS patients with cytomegalovirus retinitis.

PURPOSE To determine the frequency of cytomegalovirus glycoprotein B (gB) genotypes in clinical samples of ocular fluids of patients with acquired immune deficiency syndrome (AIDS) who have cytomegalovirus retinitis and to compare these with the cytomegalovirus gB genotype in paired peripheral blood leukocytes. METHODS Glycoprotein B genotypes of cytomegalovirus genomic DNA were determined in 29 ocular and 9 paired blood samples of 27 patients, by polymerase chain reaction amplification followed by restriction fragment length polymorphism analysis. RESULTS In the 29 ocular samples, 30 gB genotypes were determined: Glycoprotein B1 was found in 8 samples (27%), gB2 in 9 samples (30%), gB3 in 6 samples (20%), and gB4 in 3 samples (10%). In one sample, a mixed genotype was observed. In addition to these previously characterized gB genotypes, a new gB variant was observed in the ocular fluid of four patients. Partial sequence analysis revealed that this new gB genotype is closely related to gB3, and it was therefore named gB3'. In the blood samples, only gB1, gB2, and gB3 genotypes were observed. In the nine paired samples of ocular fluid and blood, four showed a difference in gB genotype between these compartments. CONCLUSIONS The distribution of cytomegalovirus glycoprotein B genotypes gB1-gB4 in ocular fluids of patients with AIDS who have cytomegalovirus retinitis was determined in this study. The predominance of gB2, as described by others, was not confirmed. The glycoprotein B genotype in the eye can be different from the genotype found in the blood of the same patient. A new gB variant, gB3', was found in the ocular samples of 4 of 27 patients, but not in the blood samples tested.