Human immunodeficiency virus type 1 antigenaemia is enhanced in patients with disseminated cytomegalovirus infection and deficient T lymphocytes

A novel pattern of pp65-positive cytomegalic endothelial cells circulating in peripheral blood from a renal transplant recipient

The present study reports a novel pattern of cytomegalic endothelial cells (CEC) in peripheral blood from a female renal transplant recipient infected with human cytomegalovirus (HCMV), which has not been reported previously. Localization of specific early antigen of HCMV, pp65 antigen, was examined by immunohistochemistry. Staining of an endothelial cell marker (CD34) was used to characterize endothelial cells. It is demonstrated that many leukocytes surrounded and adhered to a protein-like material, in which pp65-positive CEC were detected. The composition and function of this protein-like material are yet unknown. The patient lacked clinical symptoms of HCMV disease. Furthermore, similar localization patterns were found in other renal transplant recipients suffering from HCMV infections as determined by real-time PCR to detect HCMV DNA in blood. These patients showed no or only minor clinical symptoms of HCMV infection. It is suggested that these novel localization patterns of CEC may play a role in the host defense in patients infected with HCMV, but the exact relation between HCMV infection and CEC formation needs further investigation.

Cytomegalovirus infection in human immunodeficiency virus type 1-infected children

BACKGROUND

Cytomegalovirus (CMV) is a frequent opportunistic infection in human immunodeficiency virus type 1 (HIV-1)-infected children. The interactions of CMV and HIV-1 in coinfected children are not well-characterized.

OBJECTIVE

To evaluate the prevalence of asymptomatic CMV infection and symptomatic CMV disease and to assess the influence of CMV on clinical and laboratory markers of HIV disease progression in CMV-coinfected children.

METHODS

Serial urine CMV cultures were performed on 500 children (131 HIV-1-infected (HIV+), 129 seroreverters born to HIV-infected mothers, and 240 HIV-uninfected (HIV-)). The clinical, immunologic and virologic data of 131 HIV+ children were analyzed.

RESULTS

CMV was recovered in 40 of 131 HIV+ (31%), 22 of 129 seroreverters (17%) and 30 of 240 HIV- (13%) children. Of the 40 HIV+ children with CMV coinfection, 7 developed symptomatic CMV disease (17.5%) including chorioretinitis (3), colitis (2) and pneumonitis (2). The HIV+ children with symptomatic CMV disease had significantly lower mean CD4+ T lymphocyte proportions (17% vs. 26%; age-adjusted P = 0.013) and greater HIV p24 antigen concentrations (329 pg/ml vs. 57 pg/ml; age-adjusted P = 0.13) than HIV+ children with asymptomatic CMV infection. In a subset of children coinfected with CMV before 6 months of age (n = 11), 5 (45%) developed symptomatic CMV disease, and 4 of these 5 children died within 10 months of diagnosis of CMV disease. At the time of the first positive CMV culture in these children, mean CD4+ T lymphocyte proportions did not differ according to the presence or absence of CMV-related symptoms (symptomatic CMV+, 21% vs. asymptomatic CMV = 38%; P = 0.14). In HIV+ children with symptomatic CMV disease, p24 antigen concentrations were greater than in those with asymptomatic CMV infection (461 vs. 190 pg/ml, P = 0.06).

CONCLUSIONS

Symptomatic CMV disease occurred in young CMV-coinfected children with low CD4+ lymphocytes and elevated HIV p24 antigen concentrations. Whether progressive immunodeficiency allows the emergence of CMV disease or CMV infection causes more rapidly progressive HIV-1 disease or whether there is a more complex relationship remains to be determined.

CD8+ T lymphocytes and cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome

PURPOSE

We compared the levels of CD8+ and CD4+ cells in human immunodeficiency virus (HIV)-seropositive patients who had normal eye examinations, microvasculopathy, or ocular infections other than cytomegalovirus retinitis to those of patients with cytomegalovirus retinitis, to determine whether lymphocyte counts other than CD4+ are predictive of cytomegalovirus retinitis.

METHODS

The records of HIV-positive patients who had a lymphocyte subset analysis within three months of a complete eye examination were reviewed for age, gender, mode of HIV transmission, stage of disease, ocular findings, and absolute lymphocyte counts. Data for patients without cytomegalovirus retinitis were compared with those for patients with cytomegalovirus retinitis.

RESULTS

Ninety-three HIV-positive patients had a lymphocyte subset analysis within three months of a complete eye examination; 76 patients had no cytomegalovirus retinitis and 17 had cytomegalovirus retinitis. Patients without cytomegalovirus retinitis and those with cytomegalovirus retinitis had the following median cell counts: CD4+, 76.0 and 15.0 cells/microliters; CD8+, 634.5 and 280.0 cells/microliters, respectively. Patients with cytomegalovirus retinitis had significantly lower CD4+ and CD8+ cell counts than those without cytomegalovirus retinitis (P < .001). CD4+ and CD8+ cells are significantly correlated with each other, and the correlation is much higher in patients with cytomegalovirus retinitis (r = .80, P < .001) than in patients without cytomegalovirus retinitis (r = .57, P < .001). Stepwise logistic regression analysis showed that CD8+ cell counts were also predictive of cytomegalovirus retinitis.

CONCLUSION

Patients with low CD4+ cell counts are known to be at high risk for cytomegalovirus retinitis. We showed that patients with low CD8+ cell counts are also at high risk for cytomegalovirus retinitis.

The role of human cytomegalovirus in haematological diseases

Infection with HCMV in healthy individuals generally results in mild or subclinical illness. Pathogenic infections occur predominantly in immunodeficient patients, such as transplant recipients, neonates and patients with AIDS. Primary infection is frequently latent or chronic and PBLs represent sites for virus latency and persistence. HCMV can be recovered from PMNL, monocytes and T-lymphocytes. Although virus-related cases of haematopoietic dysfunction are seen infrequently in infected normal persons, the importance of HCMV as a pathogenic agent in haematopoiesis is dramatically illustrated in the case of patients receiving BMT. Primary or reactivated HCMV infections are a common feature in BMT recipients, enhancing failure of marrow engraftment, GVHD, and many opportunistic infections. HCMV can infect both haematopoietic progenitor cells and stromal elements, identifying the entire haematopoietic system as a target for HCMV dissemination and latency. As a result, lympho- and myelosuppression can be due to both direct inhibition of progenitor cell growth as well as the failure of stem cell self-renewal due to stromal cell dysfunction. HCMV can also exert suppressive effects on immune cell function by direct and indirect mechanisms. These effects can have dire consequences, particularly when a state of immunosuppression already exists, as in the HIV infection. The diverse effects of CMV on the lymphohaematopoietic system are summarized in Figure 1.

Role of CD8+ in late opportunistic infections of patients with AIDS

We studied the relationship of CD4+ and CD8+ depletion to initial and late opportunistic infections in 62 patients with AIDS. The mean interval between initial and late infections was 12.2 months. Geometric mean (and 95% confidence intervals) of T-cell counts at the diagnosis of each infection were: (Pneumocystis carinii pneumonia) CD4+ 0.051 (0.044-0.058) x 10(9)/l, CD8+ 0.561 (0.476-0.646) x 10(9)/l; (cytomegalovirus retinitis) CD4+ 0.025 (0.019-0.031) x 10(9)/l, CD8+ 0.333 (0.183-0.483) x 10(9)/l. Mycobacterium avium-intracellulare bacteraemia closely followed cytomegalovirus dissemination. Most patients were free from late opportunistic infections caused by disseminated cytomegalovirus and M. avium-intracellulare until CD8+ declined below 0.500 x 10(9)/l. Zidovudine improved CD4+, but less so CD8+, and similarly enhanced the survival of patients treated in 1985-1990 and 1991.