Human cytomegalovirus (HCMV) strains can be classified into four genotypes of the glycoprotein B (gB). In a previous study, the gB genotype 1 was found more frequently in bone marrow transplant recipients with nonfatal HCMV infection than in patients who died from HCMV disease [Fries et al. (1994): Journal of Infectious Diseases 169:769-774]. The distribution and cell tropism of different gB types in vivo were investigated. The gB type of HCMV was determined in blood or urine specimen from 76 organ and 47 bone marrow transplant recipients using PCR and restriction fragment length polymorphism (RFLP). The leukocyte populations (polymorphonuclear leukocytes, monocytes, T lymphocytes, non-T lymphocytes) of 20 viremic patients were purified by a fluorescence-activated cell sorter (FACS) and examined for HCMV infection by PCR. Sequence analysis of four randomly selected strains showed that gB types were similar to published sequences and no atypical gB types were found. Within the compartments blood and urine, the gB types were almost equally distributed, whereas the gB type 1, in contrast to gB types 2 and 3, did not infect T lymphocytes in vivo. These data show that the gB type correlates with viral tropism in vivo and thus provides further evidence that the gB variation may indeed influence the virulence of HCMV.

IgM antibodies to cytomegalovirus (CMV) could be detected in about 7 per cent of 629 pregnant women whereas in 225 nonpregnant control women of similar age distribution only 2.6 per cent showed CMV IgM antibodies. Intrauterine CMV infections were almost exclusively detected among the CMV IgM positive gravides. The high incidence of CMV IgM antibodies in pregnant women can be possibly explained by an increased rate of CMV reactivations during pregnancy. We were able to show that during CMV reactivation an intrauterine infection might occur.

A diagnostic hybridization assay for detecting human cytomegalovirus (HCMV) DNA in urine specimens was developed by using cloned viral DNA and in vitro-synthesized RNA probes. Both probes detected 3 pg of homologous DNA and hybridized with DNA of HCMV but not with other viral or human cellular DNA tested. In 95 urine specimens simultaneously tested by cell culture, the sensitivity of hybridization was at least 83%, and the specificity was at least 92%. This assay will be useful for rapid viral diagnosis with wide clinical applications such as screening of immunocompromised patients and quantitation of viral shedding in patients with primary or reactivated HCMV infection who may be receiving antiviral therapy.

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Human cytomegalovirus (HCMV) strains can be classified into four genotypes of the glycoprotein B (gB). In a previous study, the gB genotype 1 was found more frequently in bone marrow transplant recipients with nonfatal HCMV infection than in patients who died from HCMV disease [Fries et al. (1994): Journal of Infectious Diseases 169:769-774]. The distribution and cell tropism of different gB types in vivo were investigated. The gB type of HCMV was determined in blood or urine specimen from 76 organ and 47 bone marrow transplant recipients using PCR and restriction fragment length polymorphism (RFLP). The leukocyte populations (polymorphonuclear leukocytes, monocytes, T lymphocytes, non-T lymphocytes) of 20 viremic patients were purified by a fluorescence-activated cell sorter (FACS) and examined for HCMV infection by PCR. Sequence analysis of four randomly selected strains showed that gB types were similar to published sequences and no atypical gB types were found. Within the compartments blood and urine, the gB types were almost equally distributed, whereas the gB type 1, in contrast to gB types 2 and 3, did not infect T lymphocytes in vivo. These data show that the gB type correlates with viral tropism in vivo and thus provides further evidence that the gB variation may indeed influence the virulence of HCMV.