Effects of protease inhibitors on the course of CMV retinitis in relation to CD4+ lymphocyte responses in HIV+ patients

Ocular immune reconstitution inflammatory syndromes

PURPOSE OF REVIEW

The aim of this article is to review the current literature concerning immune reconstitution inflammatory syndrome in relation to the eye. The definition, epidemiology, pathophysiology, risk factors, clinical features, diagnosis and treatment are discussed.

RECENT FINDINGS

Immune reconstitution inflammatory syndrome affecting the eye has been documented in association with cytomegalovirus retinitis following the introduction of highly active antiretroviral therapy in a large number of patients. This syndrome is referred to as immune recovery uveitis, which is presumed to be mediated by recovery of immune responses specific to residual cytomegalovirus antigen located in the eye. In addition to improved immunity itself, risk factors include a low CD4 T count at the time of initiation of highly active antiretroviral therapy and involvement of a larger proportion of retina. Immune recovery uveitis is a major cause of visual loss and morbidity among patients with AIDS who are receiving highly active antiretroviral therapy.

SUMMARY

Immune recovery uveitis is the most common form of immune reconstitution inflammatory syndrome in HIV-infected patients with cytomegalovirus retinitis who are receiving highly active antiretroviral therapy. Clear clinical definitions are required for ocular immune reconstitution inflammatory syndromes to avoid misclassification of other inflammatory conditions. A multidisciplinary approach is important in the diagnosis and management of immune recovery uveitis.

INTRAOCULAR VIRAL AND IMMUNE PATHOGENESIS OF IMMUNE RECOVERY UVEITIS IN PATIENTS WITH HEALED CYTOMEGALOVIRUS RETINITIS

PURPOSE

To investigate immune and viral contributions to the pathogenesis of immune recovery uveitis (IRU), which presents as vitritis, macular edema, or formation of epiretinal membranes, and develops in patients with acquired immunodeficiency syndrome (AIDS) who experienced cytomegalovirus (CMV) retinitis before antiretroviral treatment (ART) induced immune reconstitution.

METHODS

Aqueous and vitreous fluids from patients with IRU, active CMV retinitis, and control human immunodeficiency virus (HIV)-negative, noninflamed eyes were compared for presence of cytokines IL-6, IL12, interferon gamma using enzyme-linked immunosorbent assay techniques, and CMV DNA (by polymerase chain reaction).

RESULTS

IRU eyes (11 patients, 18 samples) had the highest levels of IL-12 (median 48 pg/mL), moderate levels of IL-6 (median 146 pg/mL), and low but significant interferon gamma (median 15 pg/mL), compared to controls (P < 0.01). All uveitis eyes tested (9/9) were CMV DNA negative. In contrast, active CMV retinitis eyes were CMV DNA positive, had higher levels of IL-6 (median 349 pg/mL) (25 patients, 41 samples) than both control (P = 0.0001) and uveitis eyes (P = 0.048), similar levels of interferon gamma (median 27 pg/mL) to uveitis eyes, but less IL-12 (median 0 pg/mL) than uveitis eyes.

CONCLUSIONS

Inflammatory IRU can be differentiated from active CMV retinitis by the presence of IL-12, less IL-6, and absence of detectable CMV replication.

HIV-associated retinopathy in the HAART era

BACKGROUND

The effectiveness of highly active antiretroviral therapy (HAART) in restoring immune function in patients with acquired immunodeficiency syndrome (AIDS) has led to changes in the incidence, natural history, management, and sequelae of human immunodeficiency virus (HIV)-associated retinopathies, especially cytomegalovirus (CMV) retinitis.

METHODS

The medical literature pertaining to HIV-associated retinopathies was reviewed with special attention to the differences in incidence, management strategies, and complications of these conditions in the eras both before and after the widespread use of HAART.

RESULTS

In the pre-HAART era, CMV retinitis was the most common HIV-associated retinopathy, occurring in 20%-40% of patients. Median time to progression was 47 to 104 days, mean survival after diagnosis was 6 to 10 months, and indefinite intravenous maintenance therapy was mandatory. Retinal detachment occurred in 24%-50% of patients annually. Herpetic retinopathy and toxoplasmosis retinochoroiditis occurred in 1%-3% of patients and Pneumocystis carinii choroiditis, syphilitic retinitis, tuberculous choroiditis, cryptococcal choroiditis, and intraocular lymphoma occurred infrequently. In the HAART era the incidence of CMV retinitis has declined 80% and survival after diagnosis has increased to over 1 year. Immune recovery in patients on HAART has allowed safe discontinuation of maintenance therapy in patients with regressed CMV retinitis and other HIV-associated retinopathies. Immune recovery uveitis (IRU) is a HAART dependent inflammatory response that may occur in up to 63% of patients with regressed CMV retinitis and elevated CD4 counts and is associated with vision loss from epiretinal membrane, cataract, and cystoid macular edema.

CONCLUSIONS

The incidence, visual morbidity, and mortality of CMV retinitis and other HIV-associated retinopathies have decreased in the era of HAART and lifelong maintenance therapy may safely be discontinued in patients with restored immune function. Patients with regressed CMV retinitis, however, may still lose vision from epiretinal membrane, cystoid macular edema, and cataract secondary to IRU.

Variation of CD4+ and CD8+ T Lymphocytes as Predictor of Outcome in Renal Allograft Recipients Who Developed Acute Respiratory Distress Syndrome Caused by Cytomegalovirus Pneumonia

INTRODUCTION

We investigated the variation of CD4+ and CD8+ T lymphocytes in renal allograft recipients who developed acute respiratory distress syndrome (ARDS) caused by cytomegalovirus (CMV) infection and their relationship to patients outcome.

METHODS

Twenty one cadaveric renal allograft recipients who developed ARDS caused by CMV infection were enrolled in this study. CD4+ and CD8+ T lymphocytes were examined in peripheral blood on five occasions: the admission day (day 0) to ICU as ARDS, day 5, day 10, day 15 in ICU, and discharge day. A value taken in the second month after transplantation was assumed to be the preinfection value.

RESULTS

Among 13 surviving patients, the numbers of CD4+ and CD8+ T cells and their ratio increased as the patients recovered. The numbers of CD4+ T cells increased significantly on day 10, day 15, and at discharge day compared with day 0 (P < .05). The number of CD8+ T cells on discharge day and the ratios after day 10 were also significantly higher than those on day 0 (P < .05). In eight nonsurviving patients, the numbers of CD4+ and CD8+ T cells and their ratio was similar to day 0. The number of CD4+ and CD8+ cells after day 5 and their ratio after day 10 were significantly lower than those of survival group (P < .05).

CONCLUSION

The variations of CD4+ and CD8+ T lymphocytes and their ratio are useful indicators of the severity of disease and the outcome of patients with CMV infections accompanying ARDS after renal transplantation. Nevertheless, it may be helpful to evaluate the efficiency of ongoing treatment methods in these patients.

Paradoxical activity of CMV retinitis in patients receiving highly active antiretroviral therapy

PURPOSE

To report two types of atypical behaviors of cytomegalovirus (CMV) retinitis in the highly active antiretroviral therapy (HAART) era, including active CMV retinitis in the presence of persistently high CD4 cell counts during HAART and CMV retinitis that has not reactivated despite persistently low CD4 cell counts.

METHODS

Prospective, longitudinal, observational study of a cohort of 116 patients with acquired immunodeficiency syndrome who had a history of CMV retinitis during the HAART era.

RESULTS

Sixty (52%) of the 116 patients with acquired immunodeficiency syndrome and CMV retinitis were HAART responders. Subsequently, HAART failed for 9 of the 60 patients with low CD4 cell counts. Of these 9 patients, 5 developed reactivation of CMV retinitis, and 4 remained free of CMV retinitis despite CD4 cell counts of <50/microL and lack of anti-CMV therapy. Paradoxically, there was a patient with a documented median CD4 cell count of 204/microL for 19 months who had newly diagnosed active CMV retinitis.

CONCLUSION

In the HAART era, CMV retinitis may remain quiescent despite extremely low CD4 cell counts, and rarely, CMV retinitis may become active in the setting of persistently high CD4 cell counts in a subset of HAART responders.

Cytomegalovirus retinitis after initiation of highly active antiretroviral therapy in HIV infected patients: natural history and clinical predictors

PURPOSE

To characterize the natural course and clinical predictors of cytomegalovirus (CMV) retinitis in human immunodeficiency virus (HIV)-infected patients after initiation of highly active antiretroviral therapy (HAART).

METHODS

Retrospective analysis of 53 HIV-positive patients (73 eyes with CMV retinitis) treated with and without HAART. All participants continued to take anti-CMV therapy. Survival analysis was used to characterize the natural course of CMV retinitis. Proportional hazards analysis was performed to assess the correlation of the nine potential clinical predictors (baseline CD4 count, post-HAART CD4 count, post-HAART rise in CD4 count, baseline weight, post-HAART rise in weight, post-HAART percentage rise in weight, log of baseline HIV viral load, log of minimum post-HAART HIV viral load, and post-HAART log unit reduction in HIV viral load) with the duration of CMV retinitis remission.

RESULTS

Patients receiving HAART had a median CMV retinitis remission duration of 574 days (95% confidence interval, 336-NA) whereas those not receiving HAART had a median remission duration of 80.5 days (95% confidence interval, 28-NA; P < 0.001). Within the HAART-treated population, the minimal viral load reached after HAART was the only clinical predictor to demonstrate significance (P = 0.0075). Several other clinical predictors demonstrated borderline significance; however, this was most likely due to the high correlation of these variables with the minimum post-HAART viral load. A potential secondary clinical predictor identified was the post-HAART rise in CD4 count (P = 0.085).

CONCLUSION

With the introduction of HAART, HIV-infected patients have much longer remission durations from recurrent CMV retinitis. The minimum HIV viral load level reached after the initiation of HAART treatment appears to be more important than other clinical variables in the prediction of favorable CMV retinitis remission status. Furthermore, a rise in CD4 T-lymphocyte count by itself appears to be a less significant clinical predictor but may be useful in combination with the HIV viral load data. Selective discontinuation of anti-CMV therapy may be considered in patients with a favorable set of clinical predictors.

Diagnosis of cytomegalovirus infections by qualitative and quantitative PCR in HIV infected patients

A high incidence of cytomegalovirus (CMV) infections is observed in Brazil. These viruses are causatives of significant morbidity and mortality among patients with advanced human immunodeficiency virus (HIV) infection. This work, shows the application of a PCR on determination of CMV load in the buffy coat and plasma. We analyzed the samples of 247 HIV infected patients in order to diagnose CMV infection and disease. We developed a semi-quantitative PCR that amplifies part of the glycoprotein B (gB) gene of CMV. The semi-quantitative PCR was carried out only in positive clinical samples in a qualitative PCR confirmed by a nested-PCR. CD4 lymphocyte count, HIV viral load and CMV disease symptom were correlated with CMV load. CMV genome was detected in the buffy coat of 82 of 237 (34.6%) patients, in 10 of these the CMV load was determined varying between 928 and 332 880 viral copies/microg DNA. None of these 237 patients developed any suggestive manifestation of CMV disease. For the other 10 HIV infected patients selected based on the suspicion of CMV disease, CMV genome was detected in only one case. This patient presented a high CMV load, 8 000 000 copies/microg DNA, and developed a disseminated form of CMV disease including hepatitis and retinitis. Our results were greatly influenced by the impact of the highly active antiretroviral therapy that reduced incidence of CMV viremia and occurrence of CMV disease in the HIV infected patients.

Risk factors for cytomegalovirus retinitis following bone marrow transplantation from unrelated donors in patients with severe aplastic anemia or myelodysplasia

Two cases of cytomegalovirus (CMV) retinitis following bone marrow transplantation (BMT) from unrelated donors are reported. 1 patient had been treated for severe aplastic anemia (SAA) and the other for hypoplastic myelodysplastic syndrome (MDS). Because first line therapy with antithymocyte globulin (ATG) and cyclosporin A (CsA) had failed, BMT was performed following a conditioning regimen of ATG, cyclophosphamide, and total lymphoid irradiation. Treatment for CMV retinitis was successfully carried out with gancyclovir (systemic and intraocular injection), foscarnet, and photocoagulation (Case 1) and gancyclovir and foscarnet (Case 2). Both patients also developed Epstein-Barr virus-associated lymphoproliferative disease (EBV-LPD). We compared these 2 cases with 14 SAA patients who did not develop CMV retinitis after BMT using marrow from either HLA-identical siblings (n = 9) or from unrelated donors (n = 5). Unlike the retinitis patients, the latter 5 patients received ATG only once. The retinitis patients had significantly lower CD4+ T-cell levels in their peripheral blood than the 14 patients who did not develop CMV retinitis. We believe that repeated treatment with ATG and transplantation from unrelated donors may lead to immune dysfunction that could increase the likelihood of CMV retinitis, as well as LPD. For such BMT patients, regular ophthalmic examinations and careful testing for CMV antigenemia are recommended.

Discontinuation of maintenance therapy for cytomegalovirus retinitis in HIV-infected patients receiving highly active antiretroviral therapy

OBJECTIVE

To study the safety of discontinuing cytomegalovirus (CMV) maintenance therapy among patients with cured CMV retinitis receiving highly active antiretroviral therapy (HAART).

METHODS

Patients with a history of CMV retinitis who were receiving anti-CMV maintenance therapy and who had a CD4 cell count > 75 x 10(6) cells/l and a plasma HIV RNA level < 30000 copies/ml while on HAART were included in a multicentre prospective study. Maintenance therapy for CMV retinitis was discontinued at enrolment and all the patients were monitored for 48 weeks by ophthalmological examinations and by determination of CMV markers, CD4 cell counts and plasma HIV RNA levels. T helper-1 anti-CMV responses were assessed in a subgroup of patients. The primary study endpoint was recurrence of CMV disease.

RESULTS

At entry, the 48 assessable patients had been taking HAART for a median of 18 months. The median CD4 cell count was 239 x 10(6) cells/l and the median HIV RNA load was 213 copies/ml. Over the 48 weeks, 2 of the 48 patients had a recurrence of CMV disease. The cumulative probability of CMV retinitis relapse was 2.2% at week 48 (95% confidence interval, 0.4-11.3) and that of all forms of CMV disease 4.2%. CMV blood markers remained negative throughout follow-up. The proportion of patients with CMV-specific CD4 T cell reactivity was 46% at baseline and 64% at week 48.

CONCLUSIONS

CMV retinitis maintenance therapy may be safely discontinued in patients with CD4 cell counts above 75 x 10(6) cells/l who have been taking HAART for at least 18 months.

CD4(+) lymphocyte-mediated suppression of cytomegalovirus expression in human astrocytes

Cytomegalovirus-stimulated CD4(+) lymphocytes from seropositive but not seronegative donors suppressed viral gene expression in primary human astrocytes. This suppressive activity was mediated through soluble factors. These findings suggest that CD4(+) lymphocytes play a role in defense of the brain against cytomegalovirus.

Development of virus-specific CD4(+) T cells during primary cytomegalovirus infection

Although virus-specific CD4(+) T cells have been characterized extensively in latently infected individuals, it is unclear how these protective T-cell responses develop during primary virus infection in humans. Here, we analyzed the kinetics and characteristics of cytomegalovirus-specific (CMV-specific) CD4(+) T cells in the course of primary CMV infection in kidney transplant recipients. Our data reveal that, as the first sign of specific immunity, circulating CMV-specific CD4(+) T cells become detectable with a median of 7 days after first appearance of CMV-DNA in peripheral blood. These cells produce the T helper 1 type (Th1) cytokines IFNgamma and TNFalpha, but not the T helper 2 type (Th2) cytokine IL4. In primary CMV infection, the vast majority of these circulating virus-specific T cells have features of recently activated naive T cells in that they coexpress CD45RA and CD45R0 and appear to be in the cell cycle. In contrast, in people who have recovered from CMV infection earlier in life, virus-specific T cells do not cycle and express surface markers characteristic of memory T cells. After the initial rise, circulating virus-specific CD4(+) T cells decline rapidly. During this phase, a strong rise in IgM and IgG anti-CMV antibody titers occurs, concomitant with the reduction of CMV-DNA in the circulation.

Retrospective study of CMV retinitis in patients with AIDS

OBJECTIVES

To study the characteristics of clinical presentations and treatment outcome of patients with HIV infection who developed cytomegalovirus(CMV) retinitis.

METHODS

A retrospective study for the period 1986-97 at the regional Unit of Infectious Diseases, Newcastle General Hospital; a teaching hospital in the north-east of England. Twenty-seven patients with advanced HIV disease and clinically confirmed CMV retinitis were studied. The mean age was 40.8 years, standard deviation +/-6.3 years. The male : female ratio was 25 : 2. Twenty-six of the patients were white Caucasians and one was of Afro-Caribbean origin.

RESULT

The median time between the first AIDS-defining diagnosis and development of CMV retinitis was 1.5 years and the CD4+ cell count at the time of diagnosis of CMV retinitis was 7/mm3. After 14 months of treatment. 80% of patients on mono antiretroviral therapy had impairment of sight (visual acuity 3/60) versus 30% for those on triple antiretroviral therapy. In the same period, the survival rate was 18 versus 70% for mono versus triple antiretroviral therapy, respectively.

CONCLUSION

The outcome for patients with CMV retinitis was significantly better for those who were on triple than for those on mono antiretroviral therapy.

Detection of CMV DNA in peripheral blood leukocytes as a long-range harbinger of CMV disease in HIV-infected patients. Swiss HIV Cohort Study

The incidence of cytomegalovirus (CMV) end-organ disease can be reduced in AIDS patients by oral ganciclovir. However, the cost effectiveness of this prophylaxis is low. Targeting prophylaxis to patients with the highest risk of developing CMV disease might be useful. Several studies have shown the potential of various polymerase chain reaction (PCR) assays and of the antigenemia assay to identify the subset of patients with a definitely higher risk of developing CMV disease. We studied the CMV viral load using quantitative PCR in the leukocytes and plasma (or serum) of 28 patients in the four years before they experienced a CMV event. We observed rising CMV DNA copy numbers in the patients' leukocytes a year before the event. In contrast, plasma or serum copy numbers rose later and in fewer patients. In a control population of 21 profoundly immunodeficient patients (median CD4+ T cell count: 31/mm(3)) without history of CMV disease, only five had detectable CMV DNA in the leukocytes, three of whom had barely above-threshold levels. We suggest that, at the present time, leukocyte CMV DNA PCR might represent a sensitive test providing an early warning signal of increased risk of CMV disease. Performing it twice a year might identify patients at risk so that closer monitoring and targeted prophylaxis can be conducted.

Cytomegalovirus retinitis in advanced HIV-infected patients treated with protease inhibitors: incidence and outcome over 2 years

We prospectively studied the incidence of cytomegalovirus (CMV) retinitis in 93 patients treated with highly active antiretroviral therapy (HAART) containing a protease inhibitor (PI), during a median follow-up period of 24 months. The median initial CD4+ count was 22 cells/microl (range, 1-311 cells/microl), and the median plasma HIV viral load was 5.1 log10 copies/ml (range, 2.4-6.4 log10 copies/ml). The fundus was examined monthly in patients with a history of CMV retinitis or an initial CD4+ count <50 cells/microl and every 3 months in the other patients. Of patients with previously controlled CMV retinitis, 1 of 7 relapsed. In addition, 6 of 59 patients with a CD4+ count <50 cells/microl and no history of CMV retinitis before starting PI therapy developed CMV retinitis. Of them, 3 had at least one relapse during follow-up. CD4+ counts were <40 cells/microl at the time of primary or recurrent CMV retinitis, except in two cases (147 cells/microl and 203 cells/microl). In conclusion, the incidence of CMV retinitis was 0.091 per patient-year among study subjects with advanced HIV infection who were receiving HAART (95% confidence interval [CI], 0.037-0.145). The time to progression of CMV retinitis (mean, 215 days; 95% CI, 113-317 days) was longer than reported before widespread use of PIs.

Influence of highly active antiretroviral therapy on the development of CMV disease in HIV positive patients at high risk for CMV disease

BACKGROUND/AIMS

In the pre-HAART era, HIV positive patients with CD4+ cell counts below 50 cells x10(6)/l, and those with detectable cytomegalovirus (CMV) DNA in their peripheral blood, were considered to be at high risk for the development of CMV disease. With the start of highly active antiretroviral therapy (HAART), a restoration of immune function occurred in these patients, and as a consequence patients became less vulnerable to CMV disease. Since it is not exactly known how HAART influences CMV viral load in peripheral blood and the incidence of CMV disease in high risk HIV positive patients a group of patients was followed before and after initiation of HAART.

METHODS

29 HIV positive patients, seen in the first 3 months of 1996 at the AIDS clinic of the Academic Medical Centre, at high risk for development of CMV disease (positive CMV DNA assay in blood and/or CD4+ cell count below 50 cells x10(6)/l), not receiving anti-CMV maintenance therapy, were included in a prospective cohort study. HAART was started in the second trimester of 1996. Patients were evaluated for the occurrence of CMV retinitis, or CMV disease elsewhere, comparing the incidence of CMV events before and after the start of HAART. Following the introduction of HAART, CD4+ cell counts and quantitative polymerase chain reaction (PCR) for CMV DNA in blood were monitored in all patients who remained alive and were not receiving anti-CMV maintenance therapy (n=22). Follow up was performed until August 1998; the mean follow up after the start of HAART was 14.9 months (range 8-22 months).

RESULTS

In the pre-HAART period four patients developed CMV disease, and four died (without clinically manifest CMV disease). After the start of HAART no patient developed CMV disease or died. With HAART, the mean CD4+ cell counts increased from 34 cells x10(6)/l to 194 cells x10(6)/l at the end of follow up. CMV DNA could be detected in the blood of 11 patients. Quantification showed a decline in the amount of detectable DNA during follow up. At the last examination only one patient showed a positive PCR assay. This was the only patient with a CD4+ cell count remaining below 100 cells x10(6)/l.

CONCLUSION

In HIV positive patients at high risk of CMV retinitis, either with a positive CMV PCR assay in blood and/or with CD4+ cell counts below 50 cell x10(6)/l, HAART causes a dramatic decrease in the occurrence of CMV disease. This decrease is paralleled by an increase in CD4+ cell count, and a decrease in the amount of CMV DNA in the blood, which was below detection levels in all patients with CD4+ cell counts above 100 cells x10(6)/l.

Changing patterns of HIV related ocular disease

Cytomegalovirus (CMV) retinitis is the commonest ocular complication of AIDS and the prevention of recurrence has been dependent on lifelong maintenance treatment. Recently there has been a dramatic downturn in the number of new cases of CMV retinitis, which has been attributed to the introduction of highly active antiretroviral therapy (HAART) and subsequent improved survival. Whereas paucity of inflammation has been considered to be the hallmark of the ophthalmic manifestations of AIDS, with immune recovery, a new pattern of ophthalmic AIDS has emerged. This is characterised by a heightened inflammatory response and more frequent complications associated with this response--for example, vitritis, cystoid macular oedema. In spite of this, regression of CMV retinitis has been reported, as well as absence of reactivation or progression after withdrawal of anti-CMV maintenance treatment. How long this situation will continue is not known and we remain cautious about the future of CMV retinitis and other opportunistic ocular infections.