Cytomegalovirus genotypes present in cerebrospinal fluid of HIV-infected patients

To compare cytomegalovirus (CMV) strains found in cerebrospinal fluid (CSF) of patients with HIV infection and CMV encephalitis with those present in the general population with respect to genetic variation in the N terminus of the glycoprotein B (gBn)-gene.

We sequenced gBn, which is a major target of the antiviral immune response, of CMV strains present in CSF of nine HIV-infected patients with acute encephalitis, in serum of 18 immunocompetent patients with primary CMV infection, and in serum of nine HIV-infected patients without neurological illness. Sequences were compared to prototype strains and analysed by use of phylogeny.

Fourty-four percent (4/9) of gBn-sequences present in CSF did not cluster with any of the four gBn-prototype strains. Phylogenetic analysis revealed that these sequences represented two further, distinct genotypes and comparison of sequences was highly suggestive for intragenic recombination. In immunocompetent patients and HIV-infected patients without neurological illness, genotype gBn1 was the predominant strain (4/9, 44% and 8/18, 42%, respectively). Genotypes distinct from prototype strains were found in none of the immunocompetent patients and 22% (2/9) of HIV- infected patients without neurological illness.

CMV strains present in CSF of HIV-infected patients with encephalitis differ significantly from those present in the general population. Intragenic recombination of CMV may be common in patients with advanced HIV infection and a source of new CMV strains with altered biological properties.