CD8+ T lymphocyte counts as an adjunctive predictor of cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome

Relationship Between Opacity of Cytomegalovirus Retinitis Lesion Borders and Severity of Immunodeficiency Among People With AIDS

Purpose

To evaluate risk factors for severity of cytomegalovirus (CMV) retinitis lesion whitening (opacity), using a standardized scoring system.

Methods

We performed a cross-sectional, observational investigation of all individuals with newly diagnosed AIDS-related CMV retinitis in three randomized clinical trials and one prospective observational study. Opacity was scored by masked readers, using a prospectively defined ordinal 6-point scale. Demographic factors, laboratory data (CD4+, CD8+ T-lymphocyte counts, human immunodeficiency virus [HIV] blood levels), and lesion characteristics (location, size) were compared to the highest opacity score assigned to either eye. Among eyes with active lesions (scores ≥3), factors associated with severe opacity (scores 5, 6) were identified.

Results

There were 299 participants (401 eyes with CMV retinitis). In one or more comparisons, increased opacity was associated with lower CD4+ and lower CD8+ T-lymphocyte counts, higher HIV blood level, lack of antiretroviral therapy, male sex, race/ethnicity, and bilateral disease. In eyes with active disease, severe opacity was associated with lower CD4+ T-lymphocyte count, higher HIV blood level, older age, Karnofsky score, lesion size, and bilateral disease. No relationship was identified between opacity and lesion location.

Conclusions

Lesion border opacity (resulting from CMV activity) reflects level of immune function; as immunodeficiency becomes worse, CMV activity (and opacity) increases. The positive relationship between opacity and HIV blood level may reflect both immunodeficiency and increased CMV activity caused by transactivation of CMV by HIV. Scoring of opacity may be a useful, standard measure for continued study of CMV retinitis across different settings and populations. (Clinicaltrials.gov number for the HPMPC CMV Retinitis Trial: NCT00000142; Clinicaltrials.gov number for the Monoclonal Antibody CMV Retinitis Trial: NCT00000135; Clinicaltrials.gov number for the Ganciclovir-Cidofovir CMV Retinitis Trial: NCT0000014; Clinicaltrials.gov number for the Longitudinal Study of the Ocular Complications of AIDS: NCT00000168.).

Laboratory-based risk factors for cytomegalovirus retinitis

BACKGROUND

Very few studies have investigated risk factors for cytomegalovirus (CMV) retinitis. Identifying these risk factors will have many benefits, including helping establish screening regimens, examination frequency regimens, and targeted prophylaxis with oral therapy with valganciclovir or other anti-CMV agents. The purpose of this study was to determine the laboratory-based risk factors for CMV retinitis in patients with AIDS.

METHODS

We conducted a case-control study involving 120 patients in whom CMV retinitis had been diagnosed in 1990-99 and 159 patients without CMV retinitis from the same period. The sampling was from a primary study base in eastern Ontario and western Quebec of patients with AIDS and CD4 counts less than 50 cells/microL at the time of diagnosis of retinitis in the case subjects or an analogous date for the control subjects. There were two components to the study. In the first component (n = 279) we examined standard-of-care laboratory tests (hematologic and nutrition variables) done during the study period. In the second component (n = 57), which was a subset of the first, we examined laboratory tests (HLA type, qualitative and quantitative CMV polymerase chain reaction [PCR] and HIV load) on stored blood samples from the eastern Ontario site. Multivariate logistic regression was used to model the data and control for confounding. We developed a systematic model-building strategy, from assumption testing to model building to model checking.

RESULTS

A low hemoglobin concentration was a statistically significant predictor of CMV retinitis (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.94-0.98). Both qualitative CMV PCR (OR 21.71, 95% CI 1.80-261.67) and quantitative CMV PCR (OR 33.03,95% CI 2.32-469.39) were strong predictors of CMV retinitis. Among the 80 HLA types tested, HLA-Bw4 (OR 11.68, 95% CI 1.29-105.82) and HLA-DRB115 (OR 9.34, 95% CI 1.14-76.41) were significant predictors of CMV retinitis, whereas HLA-Cw7 was protective against CMV retinitis (OR 0.09, 95% CI 0.01-0.67).

INTERPRETATION

We have identified laboratory variables that elevate (or decrease) the risk of CMV retinitis. These findings may be useful to clinicians and health policy experts in developing rational guidelines for screening, examination frequency and targeted prophylaxis for patients with AIDS.

Sustained cytomegalovirus-specific CD4+ T cell response associated with prevention of recurrence of cytomegalovirus retinitis without secondary prophylaxis after highly active antiretroviral therapy in patients with AIDS

It has been demonstrated that the cytomegalovirus (CMV)-specific CD4(+) T cell response could be restored after ganciclovir and highly active antiretroviral therapy (HAART) in AIDS patients. In this study, we first confirmed the above observation cross-sectionally. We then performed a prospective longitudinal study over a period of 48 weeks. The second study included nine patients. All patients had received HAART. Five patients had a history of retinitis that was, however, under control after discontinuation of anti-CMV therapy more than 1 year before this study (group A). The other four had active CMV retinitis at the start of this study and anti-CMV therapy was required to control retinitis (group B). Median periods between commencement of HAART and the start of this study in group A and in group B were 27 and 4.5 months, respectively. Within both groups, the number of CD4(+) T cells that produced tumor necrosis factor alpha in response to CMV antigen did not vary throughout the observation period (Friedman test; p > 0.05). However, the median number of responsive CD4(+) T cells in group A patients was significantly higher than in group B (p < 0.05). Our results demonstrate that the number of CMV-responsive CD4(+) T cells increased when HIV was well controlled with HAART and was then maintained, and suggest that these cells may play an important role in the control of retinitis in patients with AIDS.