Recurrences of cytomegalovirus retinitis in a human immunodeficiency virus-infected patient, despite potent antiretroviral therapy and apparent immune reconstitution

EYE DISEASE IN KIDNEY TRANSPLANTATION: CLINICAL CHALLENGES IN A UNIQUE PATIENT POPULATION

Eye disease is common among kidney transplant recipients and their management is challenging. Chronic kidney disease is associated with ocular complications, both independently and in the context of various systemic disorders. In addition, chronic immunosuppression predisposes kidney transplant recipients to an array of long-term ocular issues. This may be broadly categorized into infections, malignancies, and other immunosuppression-specific side effects. The interdependence of kidney disease, transplant pharmacotherapy and ocular health therefore requires a multispecialty approach. Although the kidney transplant population has grown along with the burden of associated oculopathies, systematic guidelines targeting this patient group are lacking. This evidenced-based narrative review summarizes the pertinent issues that may present in the ophthalmic and optometric clinical settings, with emphasis on collaborative management and directions for future research.

High prevalence of gastrointestinal manifestations among Cytomegalovirus end-organ disease in the combination antiretroviral era

BACKGROUND

Cytomegalovirus (CMV) end-organ disease (EOD) continues to pose a significant risk to patients with advanced HIV disease despite decreased incidence with combination anti-retroviral therapy (ART) and lower mortality with effective anti-CMV therapy. Subclinical CMV shedding may also contribute to ongoing inflammation and non-infectious comorbidities.

METHODS

We examined the occurrence of CMV EOD and CMV shedding in a cohort of patients participating in a prospective observational study of severely immunosuppressed (CD4 ≤100 cells/μl), ART-naïve, HIV-1 infected adult participants.

RESULTS

We studied 206 participants, of whom 193 (93.7%) were CMV IgG positive. Twenty-five participants (12.1%) developed confirmed CMV EOD. At baseline, 47 (22.8%) had CMV viremia detectable by PCR in the absence of clinical disease (CMV viremia). The remaining 134 (65%) had neither CMV EOD nor CMV viremia detected at baseline. Five participants with CMV EOD (2.4% of total cohort, 20% of CMV EOD) met AIDS Clinical Trials Group criteria for CMV immune reconstitution inflammatory syndrome (IRIS). Only one-third of CMV EOD patients had retinitis, while two-thirds presented with histologically confirmed gastrointestinal illness. CMV viremia was associated with higher percentages of activated CD8+ T cells even after HIV suppression.

CONCLUSION

The manifestations of CMV EOD in advanced HIV disease before and after initiation of ART may be more diverse than previously described, with high incidence of gastrointestinal illness. Recognition and treatment of unusual clinical presentations of CMV infection remains important in reducing morbidity and mortality from HIV co-infections.

Cytomegalovirus Retinitis in Patients With Acquired Immunodeficiency Syndrome After Initiating Antiretroviral Therapy

PURPOSE

To evaluate the rates of new-onset cytomegalovirus (CMV) retinitis and worsening existing CMV retinitis in patients with AIDS after initiating combination antiretroviral therapy (cART) and the role of an immune recovery inflammatory syndrome (IRIS).

DESIGN

Cohort study.

METHODS

Immune recovery was defined as an increase in CD4⁺ T cells to ≥100 cells/μL; rates of new-onset CMV retinitis and of worsening of CMV retinitis (either increasing border activity or retinitis progression) were compared between those with and without immune recovery.

RESULTS

Among patients without CMV retinitis, 1 of 75 patients with immune recovery developed CMV retinitis in the first 6 months after initiating cART vs 1 of 31 without immune recovery (P = .14). Among patients with CMV retinitis, the rates of retinitis progression and increasing retinitis border activity among patients during the first 6 months after initiating cART in those with immune recovery were 0.11 per person-year (PY; 95% confidence interval [CI] 0-0.62) and 0.11 per PY (95% CI 0-0.62), respectively, vs 0.67 per PY (95% CI 0.22-1.56) and 0.40 per PY (95% CI 0.08-1.17), respectively, for those without immune recovery (P = .11 and .47).

CONCLUSIONS

Among persons with AIDS who experience immune recovery, there was neither an increased rate of new-onset CMV retinitis nor worsening of existing CMV retinitis in the first 6 months after initiating cART vs those without immune recovery. These data are consistent with the known 3- to 6-month lag in recovery of specific immunity to CMV after initiating cART and suggest that "immune recovery retinitis," a proposed immune recovery inflammatory syndrome phenomenon, is rare.

Association of CMV-Specific T Cell-Mediated Immunity with CMV DNAemia and Development of CMV Disease in HIV-1-Infected Individuals

BACKGROUND

Among HIV-1-infected individuals, cytomegalovirus (CMV) reactivation and disease occur in the setting of advanced immunosuppression. The value of a standardized assessment of CMV-specific T-cell mediated immunity by the CMV QuantiFERON assay (CMV-QFT) has not yet been thoroughly investigated in HIV-1-infected subjects.

METHODS

Prospective, longitudinal study in 153 HIV-1-infected subjects with a CD4+ T cell count < 350/μL who simultaneously underwent CMV-QFT, CMV serology testing and CMV-DNA quantification. Factors associated with CMV-QFT were evaluated. Clinical screening for CMV manifestations was then performed every 3 months.

RESULTS

Among the 141 CMV IgG-seropositive individuals the CMV-QFT assay yielded reactive results in 84% (118/141), negative results in 15% (21/141) and indeterminate (negative mitogen IFN-gamma response) results in 1% (2/141) of subjects. The mean actual CD4+ T cell count was significantly higher in CMV-QFT reactive subjects, when compared to CMV-QFT non-reactive individuals (183 ± 102 vs. 126 ± 104 cells/μL, P = 0.015). A significantly lower proportion of CMV-QFT reactive vs. non-reactive patients displayed CMV DNAemia > 100 copies/mL (23% (27/118) vs. 48% (11/23), P = 0.02). Furthermore, a statistically significant inverse association between mitogen IFN-gamma response and CMV-DNAemia > 1000 copies/mL was observed (P < 0.001). During the observational period, 5 CMV end-organ manifestations were observed. In three of the CMV cases the CMV-QFT yielded indeterminate results.

CONCLUSIONS

While CMV-QFT reactivity indicates CMV-specific immunity, indeterminate results due to negative mitogen IFN-gamma response might reflect HIV-1-induced immunodeficiency. Thus, dependency upon CD4+ T cell count should be considered when interpreting CMV-QFT results.

Management of ganciclovir-resistant cytomegalovirus retinitis in HIV infection in the era of antiretroviral therapy

The incidence of cytomegalovirus retinitis has decreased significantly since the advent of antiretroviral therapy. However, it remains an important problem in both the developed and developing worlds. Furthermore, long-term antiviral suppression is associated with a significant increase in viral resistance. We present the case of a 46-year-old man who developed cytomegalovirus retinitis one year after being diagnosed with HIV. While he initially demonstrated an excellent clinical response to ganciclovir, his cytomegalovirus viral load remained persistently elevated. Over the subsequent years, his virus developed ganciclovir resistance with a concomitant deterioration in his visual acuity. He responded poorly to salvage therapy with foscarnet and cidofovir. This case highlights the ongoing difficulty of managing cytomegalovirus disease nearly two decades into the era of antiretroviral therapy and underlines the need to develop new treatment strategies.

Toxoplasma encephalitis in an HIV-infected patient on highly active antiretroviral therapy despite sustained immune response

Toxoplasma encephalitis (TE) is usually diagnosed in advanced stages of HIV infection when the CD4+ count is <100–200 cells/µl. A 55-year-old woman with HIV/AIDS, well controlled on antiretroviral therapy (ART), CD4+ count in the 300 cells/μl range for >1 year presented with acute onset of headache, nausea and vomiting. She had been on her current ART regimen consisting of raltegravir, co-formulated emtricitabine/tenofovir and etravirine for three years and had been off Pneumocystis prophylaxis for 10 months (trimethoprim-sulfamethoxazole). Brain MRI showed multiple ring-enhancing, supratentorial and infra-tentorial parenchymal lesions suspicious for metastases. She had no other evidence of metastatic disease in her body. The possibilities of TE and primary CNS lymphoma were considered but deemed unlikely given the high CD4+ count. A brain biopsy demonstrated Toxoplasma tachyzoites. There was no evidence of lymphoma or carcinoma. Anti-toxoplasma treatment yielded good initial clinical and radiographic responses. While on TE maintenance therapy, she developed similar symptoms. Repeat MRI showed progression of lesions. Further work-up including CSF Epstein-Barr virus PCR and SPECT Th 201 imaging was not conclusive for CNS lymphoma. The patient’s clinical condition deteriorated and she died. We postulate that functional immunological dysfunction is a possible mechanism by which our patient developed TE despite demonstrating sustained immune response on ART.

Evaluation of the United States public health service guidelines for discontinuation of anticytomegalovirus therapy after immune recovery in patients with cytomegalovirus retinitis

PURPOSE

To evaluate United States Public Health Service (USPHS) guidelines for discontinuing anticytomegalovirus (CMV) therapy in patients with AIDS who have immune recovery and quiescent retinitis after initiating highly active antiretroviral therapy.

DESIGN

Cohort study of patients with CMV retinitis (Longitudinal Study of Ocular Complications of AIDS).

METHODS

Participants had CMV retinitis and CD4+ T-cell counts of 50 cells/μL or fewer enrolled from 1998 through 2009 who demonstrated sustained immune recovery (2 consecutive CD4+ T-cell counts of 100 cells/μL or more at least 6 months apart) and inactive retinitis. Participants were classified into 2 groups according to anti-CMV treatment after immune recover: (1) continued anti-CMV therapy and (2) discontinued therapy. We evaluated survival, visual acuity, and CMV retinitis activity; we used propensity scores to adjust for confounding factors for these analyses.

RESULTS

Of 152 participants reviewed, 71 demonstrated immune recovery, 37 of whom discontinued therapy and 34 of whom continued therapy. At immune recovery, participants continuing therapy tended to be older (44 vs 40 years; P = .09), have bilateral retinitis (53% vs 32%; P = .10), and have lower CD4+ T-cell counts (148 vs 207 cells/μL; P < .001). There were no statistical differences in any of the clinical outcomes (death, retinitis progress, visual acuity, or incidence of bilateral retinitis). Both groups lost visual acuity during follow-up, on average 1.2 letters per year (P < .01).

CONCLUSIONS

Discontinuation of anti-CMV therapy after immune recovery did not increase the risk of poor outcomes. These results support the current guidelines for discontinuation of anti-CMV therapy after achievement of sustained immune recovery.

Association of host genetic risk factors with the course of cytomegalovirus retinitis in patients infected with human immunodeficiency virus

PURPOSE

To evaluate the effects of previously reported host genetics factors that influence cytomegalovirus (CMV) retinitis incidence, progression to acquired immune deficiency syndrome (AIDS), and efficacy of highly active antiretroviral therapy (HAART) for mortality, retinitis progression, and retinal detachment in patients with CMV retinitis and AIDS in the era of HAART.

DESIGN

Prospective, multicenter, observational study.

METHODS

Cox proportional hazards model based genetic association tests examined the influence of IL-10R1_S420L, CCR5-Δ32, CCR2-V64I, CCR5 promoter, and SDF-3'A polymorphisms among patients with mortality, retinitis progression, and retinal detachment. Participants were 203 European-American and 117 African-American patients with AIDS and CMV retinitis.

RESULTS

European-American patients with the CCR5 +.P1.+ promoter haplotype showed increased risk for mortality (hazard ratio [HR] = 1.83; 95% confidence interval [CI]: 1.00-3.40; P = .05). Although the same haplotype also trended for increased risk for mortality in African-American patients, the result was not significant (HR = 2.28; 95% CI: 0.93-5.60; P = .07). However, this haplotype was associated with faster retinitis progression in African Americans (HR = 5.22; 95% CI: 1.54-17.71; P = .007). Increased risk of retinitis progression was also evident for African-American patients with the SDF1-3'A variant (HR = 3.89; 95% CI: 1.42-10.60; P = .008). In addition, the SDF1-3'A variant increased the retinal detachment risk in this patient group (HR = 3.05; 95% CI: 1.01-9.16; P = .05).

CONCLUSION

Besides overall immune health, host genetic factors influence mortality, retinitis progression, and retinal detachment in patients with AIDS and CMV retinitis that are receiving HAART.

Cytomegalovirus retinitis and the acquired immunodeficiency syndrome--bench to bedside: LXVII Edward Jackson Memorial Lecture

PURPOSE

To update information on cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS) and to integrate information on its pathogenesis and clinical outcomes.

DESIGN

Literature review.

METHODS

Selected articles from the medical literature, particularly large epidemiologic studies, including the Johns Hopkins Cytomegalovirus Retinitis Cohort Study, the Longitudinal Study of the Ocular Complications of AIDS, and the Cytomegalovirus Retinitis and Viral Resistance Study, were reviewed. Clinical information is discussed in light of knowledge on CMV, its pathogenesis, and its interactions with human immunodeficiency virus (HIV).

RESULTS

Cytomegalovirus uses several mechanisms to evade the immune system and establish latent infection in immunologically normal hosts. With immune deficiency, such as late-stage AIDS, CMV reactivates, is disseminated to the eye, and establishes a productive infection, resulting in retinal necrosis. HIV and CMV potentiate each other: CMV accelerates HIV disease, and CMV retinitis is associated with increased mortality. Randomized clinical trials have demonstrated the efficacy of treatments for CMV retinitis. Systemically administered treatment for CMV retinitis decreases AIDS mortality. Highly active antiretroviral therapy (HAART) effectively suppresses HIV replication, resulting in immune recovery, which, if sufficient, controls retinitis without anti-CMV therapy. Resistant CMV, detected in the blood, correlates with resistant virus in the eye and is associated with worse clinical outcomes, including mortality. Host factors, including host genetics and access to care, play a role in the development of CMV retinitis.

CONCLUSIONS

Clinical outcomes of CMV retinitis in patients with AIDS are dependent on characteristics of the virus and host and on HIV-CMV interactions.

Effect of nucleoside and nucleotide analog reverse transcriptase inhibitors on cell-mediated immune functions

Nucleoside analog reverse transcriptase inhibitors (NRTIs) constitute the most commonly used drugs in antiretroviral therapy. NRTIs differ with respect to their host cell toxicity. We compared the in vitro effect of zidovudine (AZT; 2 μg/ml), lamivudine (3TC; 5 μg/ml), stavudine (d4T; 1 μg/ml), and tenofovir (TFV; 1 μg/ml) on Candida cell-mediated immunity (CMI) of peripheral blood mononuclear cells (PBMCs). The concentrations of the active derivative AZT-triphosphate were 4-fold higher in Candida-stimulated compared with unstimulated PBMCs (p = 0.01), but those of 3TC-triphosphate and TFV-diphosphate did not differ significantly. AZT treatment decreased proliferation of unstimulated and Candida-stimulated PBMCs and IFN-γ ELISPOT responses; 3TC decreased proliferation of unstimulated PBMCs only; d4T and TFV decreased proliferation of Candida-stimulated PBMCs only. AZT, but not the other NRTIs, increased unstimulated PBMC apoptosis measured by caspase 3 activity. All NRTIs increased annexin-V-measured apoptosis of Candida-stimulated PBMCs. The effect of d4T on apoptosis of Candida-stimulated PBMCs strongly correlated with its inhibitory effect on mitochondrial DNA synthesis (r² = 0.94; p = 0.007). The other NRTIs did not significantly decrease the mitochondrial:nuclear DNA ratios in Candida-stimulated or unstimulated cultures, suggesting that other mechanisms mediated their effect on apoptosis and CMI. In conclusion, AZT had the most pronounced inhibitory effect on CMI. Further studies are warranted to determine the clinical significance of this observation.

Effect of host genetics on the development of cytomegalovirus retinitis in patients with AIDS

BACKGROUND

Cytomegalovirus (CMV) retinitis is a common opportunistic infection among patients with AIDS and still causes visual morbidity despite the wide spread usage of highly active antiretroviral therapy (HAART). The ubiquitous CMV pathogen contains a human interleukin-10 (IL-10) homolog in its genome and utilizes it to evade host immune reactions through an IL-10 receptor mediated immune-suppression pathway.

METHODS

Effects of IL-10R1, IL-10 and previously described AIDS restriction gene variants are investigated on the development of CMV retinitis in the Longitudinal Study of the Ocular Complications of AIDS (LSOCA) cohort (N = 1284).

RESULTS

In European Americans (n = 750), a haplotype carrying an amino acid changing variation in the cytoplasmic domain (S420L) of IL-10R1 can be protective (OR, 0.14; 95% CI, 0.02-0.94; P = .04) against, whereas another haplotype carrying an amino acid changing variation in the extracellular domain (I224V) of IL-10R1 can be more susceptible (OR, 6.21; 95% CI, 1.22- 31.54; P = .03) to CMV retinitis. In African Americans (n = 534), potential effects of IL-10 variants are observed.

CONCLUSION

Host genetics may have a role in the occurrence of CMV retinitis in patients infected with HIV.

Course of cytomegalovirus retinitis in the era of highly active antiretroviral therapy: five-year outcomes

PURPOSE

To describe the 5-year outcomes of patients with cytomegalovirus (CMV) retinitis and AIDS in the era of highly active antiretroviral therapy (HAART).

DESIGN

Prospective, multicenter, observational study.

PARTICIPANTS

A total of 503 patients with AIDS and CMV retinitis.

METHODS

Follow-up every 3 months with medical history, ophthalmologic examination, laboratory testing, and retinal photographs. Participants were classified as having previously diagnosed CMV retinitis and immune recovery (CD4+ T cells ≥ 100 cells/μl), previously diagnosed retinitis and immune compromise, and newly diagnosed CMV retinitis (diagnosis <45 days before enrollment).

MAIN OUTCOME MEASURES

Mortality, retinitis progression (movement of the border of a CMV lesion ≥ ½ disc diameter or occurrence of a new lesion), retinal detachment, immune recovery uveitis (IRU), and visual loss (< 20/40 and ≥ 20/200).

RESULTS

Overall mortality was 9.8 deaths/100 person-years (PY). Rates varied by group at enrollment from 3.0/100 PY for those with previously diagnosed retinitis and immune recovery to 26.1/100 PY for those with newly diagnosed retinitis. The rate of retinitis progression was 7.0/100 PY and varied from 1.4/100 PY for those with previously diagnosed retinitis and immune recovery to 28.0/100 PY for those with newly diagnosed retinitis. The rate of retinal detachment was 2.3/100 eye-years (EY) and varied from 1.2/100 EY for those with previously diagnosed retinitis and immune recovery to 4.9/100 EY for those with newly diagnosed retinitis. The rate of IRU was 1.7/100 PY and varied from 1.3/100 PY for those with previously diagnosed retinitis and immune recovery at enrollment to 3.6/100 PY for those with newly diagnosed retinitis who subsequently experienced immune recovery. The rates of visual loss to < 20/40 and to ≤ 20/200 were 7.9/100 EY and 3.4/100 EY, respectively; they varied from 6.1/100 EY and 2.7/100 EY for those with previously diagnosed retinitis and immune recovery to 11.8/100 EY and 5.1/100 EY for those with newly diagnosed retinitis. Although the event rates tended to decline with time, in general, at no time did they reach zero.

CONCLUSIONS

Despite the availability of HAART, patients with AIDS and CMV retinitis remain at increased risk for mortality, retinitis progression, complications of the retinitis, and visual loss over a 5-year period.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Immune reconstitution inflammatory syndrome (IRIS) associated with Cryptococcus neoformans infection in AIDS patients

Cryptococcosis is frequently associated to the immune reconstitution inflammatory syndrome (IRIS) in AIDS patients on highly active antiretroviral therapy (HAART). This study aimed to evaluate clinical and evolutive features of IRIS associated cryptococcosis patients in Uberaba, Brazil.

PATIENTS

Eighty-one AIDS individuals admitted at the teaching hospital with cryptococcal meningitis were evaluated and from these, 40 were prospectively followed. Of 40 patients with cryptococcosis, nine (22.5%) presented clinical and laboratory features of IRIS. Six (66.6%) were male, with a mean age of 37.2. Five (55.5%) presented cryptococcosis as first AIDS defining condition. In seven (77.9%) IRIS was characterised as a relapse of meningeal symptoms after 10 weeks, mean time of 72 days, of starting HAART whereas, two asymptomatic patients developed the syndrome as an unmasked cryptococcosis after 10 and 12 weeks on HAART. Lymphadenitis as isolated finding associated with IRIS was evidenced in three cases. All patients presented low CD4(+) and high RNA viral load baseline values. Cultures of cerebrospinal fluid and lymph-node fragments tissues of these cases were negative. Six of nine individuals developed high intracranial pressure requiring a daily relief lumbar puncture. No deaths occurred during the evolution of these patients. The incidence and clinical evolutive profile observed in this case series are in accordance with other reports elsewhere.

Immune restoration diseases reflect diverse immunopathological mechanisms

Up to one in four patients infected with human immunodeficiency virus type 1 and given antiretroviral therapy (ART) experiences inflammatory or cellular proliferative disease associated with a preexisting opportunistic infection, which may be subclinical. These immune restoration diseases (IRD) appear to result from the restoration of immunocompetence. IRD associated with intracellular pathogens are characterized by cellular immune responses and/or granulomatous inflammation. Mycobacterial and cryptococcal IRD are attributed to a pathological overproduction of Th1 cytokines. Clinicopathological characteristics of IRD associated with viral infections suggest different pathogenic mechanisms. For example, IRD associated with varicella-zoster virus or JC polyomavirus infection correlate with a CD8 T-cell response in the central nervous system. Exacerbations or de novo presentations of hepatitis associated with hepatitis C virus (HCV) infection following ART may also reflect restoration of pathogen-specific immune responses as titers of HCV-reactive antibodies rise in parallel with liver enzymes and plasma markers of T-cell activation. Correlations between immunological parameters assessed in longitudinal sample sets and clinical presentations are required to illuminate the diverse immunological scenarios described collectively as IRD. Here we present salient clinical features and review progress toward understanding their pathogeneses.

Human cytomegalovirus (CMV)-specific CD8+ T cell responses are reduced in HIV-infected individuals with a history of CMV disease despite CD4+ T cell recovery

Cytomegalovirus (CMV)-specific immunity was investigated in human immunodeficiency virus (HIV)-infected individuals. A case-control (1:2) study was performed with cases defined as having a history of CMV end-organ disease (n=15) and controls (n=30) matched by current CD4(+) T cell count. CMV-specific CD8(+) T cells responses were quantified using the high throughput Quantiferon-CMV test (Cellestis, Melbourne, Australia). 40/44 (91%) had a positive Quantiferon-CMV test and the magnitude of response to CMV peptides correlated significantly with response to mitogen (p<0.0001) but not with CD4(+) T cell count at the time of testing, CD4(+) T cell nadir or HIV viral load. Cases had a significantly lower Quantiferon-CMV test than controls but there was no significant difference in response to mitogen or other antigens. In individuals with a history of CMV disease, CMV-specific CD8(+) T cell responses are reduced even in the setting of CD4(+) T cell reconstitution.

Production of Monoclonal Antibodies Against Phosphoprotein 65 from Human Cytomegalovirus

Human cytomegalovirus (HCMV) has a very high infection rate in the normal population. Early diagnosis is of great value, especially in immunosuppressed individuals. HCMV phosphoprotein 65 (pp65) is the most widely used antigen for diagnosis. In this report, we prepared a monoclonal antibody against pp65, which could be used for both immunohistochemistry and Western blot diagnosis of HCMV infection.

Evolving characteristics of toxoplasmosis in patients infected with human immunodeficiency virus-1: clinical course and Toxoplasma gondii-specific immune responses

Toxoplasmic encephalitis (TE) is the most important opportunistic infection of the central nervous system in patients infected with human immunodeficiency virus (HIV)-1. This study evaluated the effect of highly active anti-retroviral therapy (HAART) and Toxoplasma gondii-specific immune responses on the occurrence of TE. The clinical characteristics of all patients diagnosed with TE in two centres since 1990 (n = 140) were analysed. Patients were grouped according to the date of diagnosis (period 1, 1990-1993; period 2, 1994-1996; period 3, 1997 onwards). Immune responses to T. gondii were evaluated in a subgroup (n = 12) by interferon (IFN)-gamma-specific ELISPOT tests. There were marked differences in the estimated Kaplan-Meier overall survival (OS), with a 1-year OS (5-year OS) of 41% (7%) in period 1, 56% (29%) in period 2, and 90% (78%) in period 3 (p <0.0001). In period 3, TE was found to be the first AIDS-defining illness more frequently than in earlier periods (74% vs. 38%, p 0.0002). Persistent neurological deficits caused by TE were present in 37% of the patients. Patients with an acute episode of TE or a TE relapse had significantly lower responses in the T. gondii-specific ELISPOT than patients who discontinued maintenance therapy and were relapse-free (p 0.0044). Survival of HIV patients with TE has improved markedly since the introduction of HAART, but persistent neurological deficits are often present in surviving patients. While preventive therapy remains essential, evaluation of T. gondii-specific immune responses may be an important step in improving estimates of the individual risk of TE and TE relapses.

Susceptibility to opportunistic infections in HIV-infected patients with increased CD4 T-cell counts on antiretroviral therapy may be predicted by markers of dysfunctional effector memory CD4 T cells and B cells

OBJECTIVES

HIV-infected patients responding to combination antiretroviral therapy (ART) after experiencing severe immunodeficiency may exhibit persistent immune defects and occasionally experience opportunistic infections (OIs) despite increased CD4 T-cell counts. The investigation of immune defects in such patients was examined in this study.

METHODS

CD4 effector memory T-cell (T(em)-cell) function [assessed by blood cytomegalovirus (CMV) interferon-gamma (IFN-gamma) enzyme-linked immunosorbent spot-forming cell assay (ELISPOT) counts] and B-cell dysregulation [assessed by serum immunoglobulin A (IgA) and IgE levels] were examined in 27 patients with increased CD4 T-cell counts after receiving ART for over 2 years. Two of these patients and one other had developed OIs on ART and are described in detail.

RESULTS

Serum levels of IgA and IgE were higher than reference intervals (P<0.001) and CMV IFN-gamma ELISPOT counts were lower than those in non-HIV-infected controls (P<0.001) in the HIV-infected patients. Low CMV IFN-gamma ELISPOT counts were associated with high IgA levels (r=-0.5, P=0.01, Spearman's correlation test) and segregated with high IgE levels (P=0.06, Fisher's test). CMV IFN-gamma ELISPOT counts and serum IgA and IgE levels did not change significantly over a median time of 35 (range 8-60) months after the first measurement, whereas CD4 T-cell counts increased. All three patients who experienced OIs had repeatedly low CMV IFN-gamma ELISPOT counts and increased serum levels of IgA and/or IgE.

CONCLUSION

Low CD4 T(em)-cell function and B-cell dysregulation are immune defects that may persist independently of changes in the CD4 T-cell count in HIV-1-infected patients responding to ART and are associated with an increased risk of developing an OI.

Longitudinal Study of the Ocular Complications of AIDS

OBJECTIVE

To report the prevalence of ocular complications of AIDS in the era of highly active antiretroviral therapy (HAART).

DESIGN

Cohort study.

PARTICIPANTS

Patients with AIDS, 13 years or older.

METHODS

History, eye examination, and laboratory testing at enrollment.

MAIN OUTCOME MEASURE

Frequency of ocular complications at enrollment.

RESULTS

As of March 31, 2003, 1632 participants with AIDS were enrolled. The cohort had a history of severe immune deficiency, as evidenced by a median nadir CD4+ T-cell count of 30 cells per microliter. At enrollment, the median CD4+ T-cell count was 164 cells per microliter. CD4+ T-cell counts were <50 in 24.1% but > or =100 in 63.6% and > or =200 in 43.0%. Cytomegalovirus (CMV) retinitis was present in 22.1%, whereas other ocular opportunistic infections each were present in < or =0.6%. The incidence of CMV retinitis estimated from retrospective data was 5.60/100 person-years. Of the 360 patients with CMV retinitis, 22.5% were newly diagnosed at enrollment, and the remainder had more long-standing CMV retinitis (median, 2.8 years).

CONCLUSIONS

Although there is the possibility of oversampling patients with AIDS and ocular complications (as compared with a random sample), which would lead to increased estimates of prevalent and incident ocular morbidities, these data still suggest a substantial decline in the incidence of CMV retinitis from the pre-HAART era. Nevertheless, new cases of CMV retinitis continue to occur, and there is a population of patients with long-standing retinitis who will require management.

Human retinal and brain cell lines: A model of HCMV retinitis and encephalitis

Although HIV is accepted as the etiologic agent in AIDS, other factors have been implicated in accelerating the disease. Human cytomegalovirus (HCMV) in particular has been implicated as a cofactor in the progression from AIDS-related complex (ARC) to AIDS. HCMV infection of the central nervous system (CNS) (brain, retina) has been reported in at least 50% of AIDS patients, and has been implicated in producing encephalitis and sight-threatening retinitis. HCMV exhibits strict species specificity and animal models for human HCMV are conspicuous by their absence. We have developed a human brain cell line (mixed glial/neuronal) and a multipotential human retinal precursor cell line (neuronal in nature). We have tested the suitability of these cell lines as models for the study of HCMV infectibility. In this study, we report that these cell lines are optimal for the study of HCMV infectibility and pathogenesis in tissues of neural origin and appropriate to study HIV-HCMV interaction. Immortalized human brain and retinal cell lines were infected with a laboratory strain of HCMV (AD 169, Towne) at a multiplicity of infection moi (1-5) and viral infectibility and cell specificity monitored by: (a) phenotypic analysis (multinucleate cells, syncytium formation, etc.), (b) antigen expression (IE, E, late) by immunohistochemistry, Western blot analysis, (c) presence of viral particles by TEM, and (d) expression of indicator plasmids (HIV-LTR-CAT). We report that both human retinal and brain cell lines are permissive for HCMV infectibility. Cell specificity was not seen; both cells expressing glial/neuronal cell markers were positive for the presence of HCMV early/late antigens. Formation of multinucleate giant cells with nuclear inclusion bodies and syncytia were seen. Productive viral infection was confirmed by the ability of cell-free supernatant from the third passage of infected cells to produce pathogenicity and express viral particles, when added to fresh cultures. Using indicator plasmids, HIV-LTR, and CAT, we have shown that HIV and HCMV interact at the cellular level. We have also shown that HIV production in retinal and brain cell lines transfected with cloned HIV was enhanced by HCMV-IE genes. We did not see any differences in HCMV. AD 169, Towne isolate, and data from both strains is presented in this paper. This model could prove extremely useful for the study of cell specificity/cellular and molecular interaction between HIV/HCMV and to test antiviral therapies.

Regulatory T cells generated during cytomegalovirus in vitro stimulation of mononuclear cells from HIV-infected individuals on HAART correlate with decreased lymphocyte proliferation

HIV-infected patients fail to fully recover cell-mediated immunity despite HAART. To identify regulatory factors, we studied the phenotype and function of in vitro cytomegalovirus (CMV)-stimulated T cells from HAART recipients. CFSE-measured proliferation showed CD4+ and CD8+ cells dividing in CMV-stimulated cultures. Compared with healthy controls, CMV-stimulated lymphocytes from HAART recipients had lower 3H-thymidine incorporation; lower IFNgamma and TNFalpha production; higher CD4+ CD27- CD28- and CD8+ CD27- CD28- frequencies; lower CD4+ CD25hi; and higher FoxP3 expression in CD8+ CD25hi cells. CMV-specific proliferation correlated with higher IFNgamma, TNFalpha and IL10 levels and higher CD4+ perforin+ and CD8+ perforin+ frequencies. Decreased proliferation correlated with higher CD4+ CD27- CD28- frequencies and TGFbeta1 production, which also correlated with each other. Anti-TGFbeta1 neutralizing antibodies restored CMV-specific proliferation in a dose-dependent fashion. In HIV-infected subjects, decreased proliferation correlated with higher CMV-stimulated CD8+ CD25hi frequencies and their FoxP3 expression. These data indicate that FoxP3- and TGFbeta1-expressing regulatory T cells contribute to decreased immunity in HAART recipients.

Disseminate and fatal cytomegalovirus disease with thymitis in a naive HIV-patient after early initiation of HAART: Immune restoration disease?

We describe a naive HIV-infected patient who developed a Pneumocystis carinii pneumonia and disseminate and fatal cytomegalovirus disease within 3 months after initiation of HAART, suggesting due to coincidence in time, an immune restoration disease. We propose an alternative hypothesis.

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.

Course of cytomegalovirus retinitis in the era of highly active antiretroviral therapy: 1. Retinitis progression

PURPOSE

To describe the course of cytomegalovirus (CMV) retinitis in patients with AIDS in the era of highly active antiretroviral therapy (HAART).

DESIGN

Multicenter, prospective, observational study.

PARTICIPANTS

Two hundred seventy-one patients with AIDS and CMV retinitis.

METHODS

Follow-up every 3 months with medical history, ophthalmologic examination, laboratory testing, and fundus photographs. Photographs were evaluated for relapse of the retinitis (progression) by graders at a centralized reading center.

MAIN OUTCOME MEASURE

Retinitis progression (movement of the border of a CMV lesion > or =750 microm over a > or =750-microm front or occurrence of a new lesion one-quarter disc area or more in size).

RESULTS

The overall rate of retinitis progression was 0.10/person-year (PY); among those with CD4+ T-cell counts of <50/microl, it was 0.58/PY, compared to 0.02/PY among those with CD4+ T-cell counts of > or =200/microl (P<0.0001). In the multivariate analysis, significant risk factors for retinitis progression included a low CD4+ T-cell count, positive CMV load, longer time from AIDS diagnosis, and low Karnofsky score.

CONCLUSIONS

Compared with the rate of retinitis progression (approximately 3.0/PY) reported in the pre-HAART era, the rate of retinitis progression was reduced among patients in the HAART era, even among those with low CD4+ T-cell counts, who might be expected to behave most like patients from the pre-HAART era. However, these events also occurred among patients with high CD4+ T-cell counts and presumed immune recovery. Continued ophthalmologic follow-up of patients with immune recovery is recommended to detect early retinitis progression.

Restoration of CD4 T-cell responses to cytomegalovirus is short-lived in severely immunodeficient HIV-infected patients responding to highly active antiretroviral therapy

OBJECTIVES

To define the level of pathogen-specific immune reconstitution persisting over 3 to 5 years of highly active antiretroviral therapy (HAART) in HIV-infected patients who began therapy with CD4 T-cell counts below 50 cells/microL.

METHODS

Cytomegalovirus (CMV)-specific T-cell responses were analysed in adult HIV-1-infected patients with nadir CD4 T-cell counts below 50 cells/microL before HAART. CMV-specific CD4 T-cell responses were measured by interferon-gamma enzyme-linked immunospot assay (ELISpot assay), lymphoproliferation and interferon-gamma levels in cell culture supernatants.

RESULTS

CD4 T-cell responses to CMV were low in untreated patients and remained low during the first year on HAART, but increased progressively to levels similar to those found in HIV-seronegative CMV-seropositive controls at 3 years. Responses then declined markedly and at 5 years were lower than controls. This could not be explained by changes in CD4 or CD8 T-cell counts or plasma HIV RNA levels. Interferon-gamma and interleukin-5 responses to a mitogen were maintained or elevated.

CONCLUSIONS

CMV-specific CD4 T-cell responses were found to decline after 3-5 years on HAART and may provide inadequate long-term protection against CMV disease in patients who are severely immunodeficient prior to treatment.

Canadian consensus guidelines for the management of cytomegalovirus disease in HIV/AIDS

BACKGROUND

The management of HIV-infected patients with cytomegalovirus (CMV) disease has changed significantly with the availability of highly active antiretroviral therapy (HAART).

OBJECTIVES

These updated guidelines are intended to provide practical help to physicians managing HIV-positive patients with or at risk for CMV disease.

METHODS

The 10 members of the Canadian CMV Disease in HIV/AIDS Consensus Group were infectious disease specialists, a primary care physician and ophthalmologists with expertise in HIV and CMV infection. Financial support by Hoffmann-La Roche Canada Ltd was unrestricted, and was limited to travel expenses and honoraria. The consensus group met in June and October 2002. Key areas to be considered were identified, and group members selected, reviewed and presented relevant recent literature for their assigned section for the group's consideration. Evidence was assessed based on established criteria, which were expert opinions of the members. Draft documents were circulated to the entire group and modified until consensus was reached. The final guidelines represent the group's consensus agreement. The guidelines were approved by the Canadian Infectious Disease Society.

RESULTS AND CONCLUSIONS

The guidelines address symptom monitoring, screening for early detection and prevention, and treatment using oral, intravenous and intraocular anti-CMV therapies in conjunction with HAART.

Cytomegalovirus infection in the era of HAART: fewer reactivations and more immunity

The incidence of cytomegalovirus (CMV) disease, once the most common and highly feared viral complication of AIDS, has dramatically decreased with the advent of highly active antiretroviral therapy (HAART). HAART-associated changes in the epidemiology of CMV disease resulted from the increase in CMV-specific immune responses coupled with the decrease in CMV reactivation. However, CMV disease continues to afflict HIV-infected patients on HAART when CD4+ cell counts fail to rise above 100 cells/mm(3) and when reconstitution of normal CMV-specific immune responses does not occur. The latter scenario may lead to recurrent or de novo CMV end-organ disease, or to the recently described CMV immune recovery vitritis. HAART-associated immune reconstitution offers unique opportunities to investigate the virological and immunological correlates of protection against CMV disease. Although the full extent of CMV-specific immune reconstitution has not been defined thus far, CMV-specific interferon-gamma production has been shown to be significantly associated with protection against CMV reactivation and recurrent disease.

Antimicrobial-Specific Cell-Mediated Immune Reconstitution in Children with Advanced Human Immunodeficiency Virus Infection Receiving Highly Active Antiretroviral Therapy

To identify virological and immunological correlates of microbial-specific immune reconstitution in children with advanced human immunodeficiency virus (HIV) infection, Candida- and tetanus-specific lymphocyte proliferation was measured in 165 children initiating a new highly active antiretroviral therapy (HAART) regimen. During the study, the proportions of children with immunity to Candida and tetanus increased from 53% to 66% and 19% to 22%, respectively. Tetanus immunity was associated with an HIV load < or =400 RNA copies/mL and with Candida immunity. At the end of the study, 23% of the patients with baseline negative lymphocyte proliferation had tetanus immunity, and 65% had Candida immunity. Reconstitution of tetanus immunity correlated with lower end-of-study HIV loads and activated CD8+ cell percentages and higher baseline and in-study CD4+ cell percentages, but not with a gain of CD4+ cells. Reconstitution of Candida immunity showed similar trends. In conclusion, children with advanced HIV infection receiving HAART reconstituted Candida immunity more readily than they did tetanus immunity, suggesting a role for antigen reexposure. Additional factors for immune reconstitution were low HIV load, high CD4+ cell percentages, and low levels of activated CD8+ cells.

IL-23 and IFN-gamma deficiency in immunodeficient HIV patients who achieved a long-term increase in CD4 T-cell counts on highly active antiretroviral therapy

The pathogenesis of HIV infection and the susceptibility to opportunistic infections has been associated with poor type 1 cytokine production. In severely immunodeficient HIV patients who achieved increased CD4 T-cell counts on longterm highly active antiretroviral therapy, we observed reduced expression of IL-23p19 and IFN-gamma messenger RNA. Impaired IL-23-induced IFN-gamma production by memory T cells might thus contribute to opportunistic infections in a minority of patients with substantial CD4 T-cell recovery.

Adverse events of desirable gain in immunocompetence: the Immune Restoration Inflammatory Syndromes

Augmentation of inflammation may occur during immune reconstitution in a immunocompromised host. This phenomenon is able to cause atypical inflammatory disorders, synonymously summarized as 'Immune Reconstitution Syndrome', 'Immune Restoration Disease' and 'Immune Restoration Inflammatory Syndrome' (IRIS). Immune reconstitution occurs, if temporarily use of immunosuppressive agents was terminated or if highly active antiretroviral therapy in human immunodeficiency virus positive individuals with secondary immunodeficiency was initiated. Unexpected deterioration of inflammatory disease and atypical clinical features, resembling symptoms of autoimmune disease may arise. They have to be distinguished from intercurrent infection and rheumatic disease, respectively. Treatment of IRIS would consist of both potential differential diagnoses: use of anti-inflammatory and immunosuppressive drugs like in autoimmune disorders as well as antimicrobial chemotherapy to decrease the burden of pathogen like in infectious disease. Therefore, awareness for IRIS is of increasing importance from a clinical point of view. However, diagnostic criteria and standards of treatment still have to be defined.

Immune reconstitution in HIV-infected patients

The prognosis of patients infected with human immunodeficiency virus (HIV) type 1 has dramatically improved since the advent of potent antiretroviral therapies (ARTs), which have enabled sustained suppression of HIV replication and recovery of CD4 T cell counts. Knowledge of the function of CD4 T cells in immune reconstitution was derived from large clinical studies demonstrating that primary and secondary prophylaxis against infectious agents, such as Pneumocystis jirovecii (Pneumocystis carinii), Mycobacterium avium complex, cytomegalovirus, and other pathogens, can be discontinued safely once CD4 T cell counts have increased beyond pathogen-specific threshold levels (usually >200 CD4 T cells/mm3) for 3-6 months. The downside of immune reconstitution is an inflammatory syndrome occurring days to months after the start of ART, with outcomes ranging from minimal morbidity to fatal progression. This syndrome can be elicited by infectious and noninfectious antigens. Microbiologically, the possible pathogenic pathways involve recognition of antigens associated with ongoing infection or recognition of persisting antigens associated with past (nonreplicating) infection. Specific antimicrobial therapy, nonsteroidal anti-inflammatory drugs, and/or steroids for managing immune reconstitution syndrome should be considered.

Posterior segment manifestations of HIV/AIDS

The ocular posterior segment manifestations of AIDS may be divided into four categories: retinal vasculopathy, unusual malignancies, neuro-ophthalmologic abnormalities, and opportunistic infections. Microvasculopathy is the most common manifestation. Opportunistic infections, particularly cytomegalovirus retinitis and progressive outer retinal necrosis, are the most likely to result in visual loss due to infection or subsequent retinal detachment. Diagnosis and treatment are guided by the particular conditions and immune status of the patient.

Fibrovascular Changes Misdiagnosed as Cytomegalovirus Retinitis Reactivation in a Patient with Immune Recovery

A patient with human immunodeficiency virus infection and cytomegalovirus (CMV) retinitis developed immune recovery uveitis as a result of receipt of highly active antiretroviral therapy. Fibrovascular changes occurred in the CMV retinitis scar, were misdiagnosed as CMV retinitis reactivation, and were treated with anti-CMV medication. Fibrovascular membranes can be misdiagnosed as reactivated CMV retinitis, and a proper diagnosis is essential to avoid unnecessary therapy with potentially toxic antiviral medications.

Cytomegalovirus-specific IFN-gamma production is associated with protection against cytomegalovirus reactivation in HIV-infected patients on highly active antiretroviral therapy

OBJECTIVES

To identify the predictors of cytomegalovirus reactivation in AIDS patients on highly active antiretroviral therapy (HAART).

DESIGN

This prospective study enrolled cytomegalovirus-seropositive AIDS patients on or about to start HAART, who were not receiving anti-cytomegalovirus prophylaxis. Clinical and laboratory data were collected over 3.5 years at clinic visits, which coincided with the study visits.

METHODS

Blood was obtained at every study visit and was used for measurements of cytomegalovirus cell-mediated immunity (lymphocyte proliferation, IFN-gamma, IL-2, and IL-10 production), cytomegalovirus viral load, CD4 cell count, and HIV viral load. A logistic-normal model was used to analyse outcome data with repeated observations.

RESULTS

Twenty-six patients had 40 episodes of cytomegalovirus reactivation (positive cytomegalovirus viral load) during the study. Their immunological and virological parameters were compared with 26 randomly selected control individuals from the same cohort. The risk of cytomegalovirus reactivation significantly decreased with every 6-month increase in HAART duration [odds ratio (OR) 0.5; P = 0.02] and marginally increased with every log10 RNA copies/ml HIV viral load (OR 2; P = 0.07). CD4 cell counts, cytomegalovirus lymphocyte proliferation, IL-2, and IL-10 did not reach significance as predictors of cytomegalovirus reactivation. However, cytomegalovirus IFN-gamma production significantly decreased the risk of cytomegalovirus reactivation (OR 0.03; P = 0.04).

CONCLUSION

Cytomegalovirus-specific IFN-gamma has a unique value as an immunological predictor of cytomegalovirus reactivation, demonstrating the importance of cellular immune responses in the control of cytomegalovirus replication in HAART recipients.

Immune Restoration Inflammatory Syndromes: The Dark Side of Successful Antiretroviral Treatment

The prevalence of cellular immunodeficiency has increased due to rising use of immunosuppressive therapies and the pandemic spread of HIV infection. More recently, the introduction of highly active antiretroviral therapy (HAART) in HIV has led to significant immune reconstitution, even in patients with previously long-lasting secondary immunodeficiency. HAART reduces morbidity and mortality in HIV infection and also changes the clinical course of prevalent subclinical opportunistic infections or autoimmune diseases. Atypical inflammatory disorders develop after initiation of HAART and have been summarized as "immune reconstitution syndrome," "immune restoration disease," and "immune restoration inflammatory syndrome." However, diagnostic criteria and standards of therapy are yet to be defined. The awareness for these diseases is of increasing importance from a clinical point of view. This review summarizes the variety of immunoreconstitution disorders and describes possible diagnostic pitfalls. We also propose possible therapeutic options.

Partial restoration of cytokine profile despite reconstitution of cytomegalovirus-specific cell-mediated immunity in human immunodeficiency virus-infected patients during highly active antiretroviral treatment

We reconstituted cytomegalovirus (CMV)-specific T-cell responses in human immunodeficiency virus-1-positive, CMV-positive patients receiving highly active antiretroviral treatment (HAART). We used several combinations of functionality parameters to determine the degree of T-lymphocyte reconstitution obtained during 1 year of treatment. Untreated patients displayed CMV-specific cytotoxic T-lymphocyte (CTL) activity despite the absence of CMV-specific lymphoproliferative responses (LPRs) and despite the fact that interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) were not secreted. The absence of LPRs, IFN-gamma and IL-2 before antiretroviral treatment suggests that CMV-specific immunity was deregulated despite the high CD4+ T-cell counts presented by our cohort, which are critical to the reactivation of CMV disease. After 6 months of HAART, CTL activity had increased compared with the baseline, as had the levels of secreted IFN-gamma and LPR. However, the levels of specific IL-2 produced did not change during therapy, and no specific IL-2 was detected during the follow-up period. Taken together, our findings suggest that 1 year of HAART led to the recovery of some, but not all, CMV-specific responses in our cohort of patients.

Multiple relapses of human cytomegalovirus retinitis during HAART in an AIDS patient with reconstitution of CD4+ T cell count in the absence of HCMV-specific CD4+ T cell response

BACKGROUND

While in the past human cytomegalovirus (HCMV) represented the major viral opportunistic pathogen in patients with AIDS, incidence of HCMV disease in HIV-infected patients drastically dropped after introduction of highly active antiretroviral therapy (HAART). However, cases of HCMV disease in HIV-infected patients treated with HAART have been reported.

OBJECTIVE

A 38-year-old HIV-infected patient developed HCMV retinitis in May 1999 after reaching a nadir of 69 CD4(+) T cells/microl. HAART and anti-HCMV treatments with parenteral ganciclovir (GCV) were started, resulting in HIV viremia suppression, rise in CD4(+) T cell count to >300 cells/microl and recovery from retinitis. Notwithstanding the apparent immune reconstitution, every attempt to discontinue GCV maintenance treatment was followed by a relapse of retinal lesions. Thus, HCMV-specific CD4(+) cellular immune response was investigated.

RESULTS

Lymphoproliferation assay and cytokine flow cytometry analysis were performed repeatedly from November 1999 showing absolute lack of HCMV specific CD4(+) T cell response, in the presence of an efficient lymphoprolipherative response against another pathogen (Candida) or a mitogen (Phytohemoagglutinin).

CONCLUSION

In some patients, immune reconstitution after HAART may be only partial, since lack of pathogen-specific CD4(+) T cell response may persist even in the case of a significant rise in the absolute CD4(+) T cell count. This case suggests that immunologic assays investigating specific immune response against HCMV in HIV infected patients may be more useful than the CD4(+) T cell count alone in assessing immune function reconstitution after HAART and in deciding interruption of anti-HCMV secondary prophylaxis.

The role of immune reconstitution in cytomegalovirus infection

Cytomegalovirus (CMV) causes high morbidity and mortality in immunocompromised patients. The host immune response to CMV comprises specific and nonspecific cellular and humoral responses, but current knowledge supports a protective role only for cell-mediated immune responses. Although complete CMV eradication is unusual even in immunocompetent hosts, its morbidity can be limited by CMV-specific CD8+ cytotoxic lymphocytes supported by CD4+-mediated T lymphocyte helper activity. In patients with congenital or acquired deficiencies of cell-mediated immunity, recovery of CD4+ lymphocyte numbers and/or function coincides with cessation of CMV-associated morbidity. However, an immunological test that can predict protection against CMV disease across different types of high-risk patients is not yet available. In recent years, the introduction of antivirals active against CMV has improved the outcome of CMV disease. In addition, there is a continuous effort to develop CMV-specific immune-based therapies including vaccines and immune modulators such as cytokines, which may be of supplemental benefit in the control of CMV disease.

Persisting murine cytomegalovirus can reactivate and has unique transcriptional activity in ocular tissue

Cytomegalovirus (CMV) retinitis is an important ocular complication in human immunodeficiency virus-infected individuals and the leading cause of blindness in those not undergoing highly active antiretroviral therapy. Murine CMV (MCMV) infection of mice has been shown to be a useful small-animal model for the study of CMV pathogenesis in the eye. The purpose of this study was to evaluate CMV persistence in ocular tissue and to determine the potential for reactivation. Following subretinal inoculation of immunocompetent BALB/c mice, tissues were tested for infectious virus by plaque assay and for the presence of viral DNA and RNA by PCR. The latent phase of the infection in mouse tissues was analyzed by plaque assay, PCR, and explantation cocultivation in both immunocompetent and cyclophosphamide-treated mice. The acute phase of the infection was resolved by 2 to 3 weeks postinfection, while viral DNA persisted beyond 12 months. Immediate-early 1 transcripts were detected in 100% of the ocular samples tested, and glycoprotein H transcripts were detected in 86% of the samples, but no difference in viral DNA or RNA levels between immunocompetent and immunosuppressed animals was measured. Irrespective of immune status, no in vivo reactivation was detected; however, reactivated virus was observed in 76 to 82% of the eyes following explantation onto a permissive cell layer. The transcriptional activity and relatively high frequency of explantation-induced reactivation in both immunocompetent and immunosuppressed mice suggest that control of MCMV latency in ocular tissue might involve other regulatory events that are not entirely dependent on intact specific immunity.

New developments in laboratory monitoring of HIV-1 infection

The laboratory tests currently available to the clinician for day-to-day management of HIV infection are generally limited to the measurement of the viral load and of the CD4 cell count. More recently, analysis of drug resistance and of plasma drug levels have been added to the monitoring armamentarium. There are, however, numerous other techniques currently available to researchers that may in the future be incorporated into clinical routine. These include the analysis of human and viral genetic determinants of disease evolution, detailed analyses of immune recovery and reserve, pharmacogenetic determinants of treatment response, and toxicity. These approaches may in the future provide highly individualized disease management.

Clinical indicators of immune restoration following highly active antiretroviral therapy

The course of human immunodeficiency virus (HIV) disease is characterized by a progressive decline in immune function. The advent of highly active antiretroviral therapy (HAART) has allowed patients to experience a significant degree of immune restoration when compared with the era before the availability of HAART. Multiple studies, which have employed sophisticated in vitro measures of immune function, have demonstrated improvement in CD4(+) lymphocyte (T4) responses to various opportunistic pathogens. In addition, for patients treated during acute HIV infection, HIV-specific T4 responses have been restored. By contrast, there are a limited number of in vivo measures of T4 function available to assess immune recovery following initiation of HAART. The primary measurement is an increase in CD4 lymphocyte count, the significance of which may be underappreciated. Delayed-type hypersensitivity testing to recall antigens and serological response to prophylactic vaccines may also have a role. This review discusses available markers of immune function and offers suggestions regarding their use in HAART recipients.

Declining levels of rescued lymphoproliferative response to human cytomegalovirus (HCMV) in AIDS patients with or without HCMV disease following long-term HAART

OBJECTIVE

To investigate the lymphoproliferative response (LPR) to human cytomegalovirus (HCMV) in two groups of AIDS patients undergoing long-term highly active antiretroviral therapy (HAART): group 1 ( n = 22) with nadir CD4(+) cell count <50/microl and no HCMV disease; group 2 ( n = 16) with <50/microl CD4(+) T-cell count and HCMV disease. All patients had previously undergone antiretroviral monotherapy or dual therapy before initiating HAART.

STUDY DESIGN AND METHODS

The two groups of patients were tested prospectively for CD4(+) T cell count, HIV RNA load, HCMV viremia, and LPR to HCMV at baseline, and then after 3 and 4 years of HAART. A control group of 13 recently diagnosed treatment-naive AIDS patients with CD4(+) T-cell counts <100/microl was also investigated.

RESULTS

No LPR to HCMV was found in any of the treatment-naive patients nor in any patient of the two groups examined at baseline, when HCMV viremia was 13.6% in the patient group without disease and 87.5% in the group with disease ( p <.0001). After 3 years of HAART, the frequency of patients who recovered an LPR to HCMV was not significantly different (81.8% in the group without HCMV disease, and 68.7% in the group with HCMV disease), whereas, compared with baseline, the HIV load decreased and the CD4(+) T-cell count increased significantly and to a comparable extent in the two groups of patients. In addition, the frequency of patients with HCMV viremia, although reduced, became comparable in both groups. After 4 years of HAART, the frequency of responders to HCMV without and with HCMV disease dropped to comparable levels (50.0 vs. 56.3%, respectively) in association with high median CD4(+) T-cell counts and low median HIV RNA plasma levels. In parallel, the frequency of patients with HCMV viremia did not change significantly. In addition, after between 3 and 4 years of HAART, although the frequency of stable responders and nonresponders remained unchanged (50%) in both groups, most of the remaining patients showed declining levels of responsiveness to HCMV. Although some patients from both groups were found to have CD4(+) T-cell counts >150/microl in the absence of LPR to HCMV, thus suggesting dissociation of specific and nonspecific immune reconstitution, a significant correlation was found between CD4(+) T-cell count and LPR to HCMV (r = 0.44; p <.001). From a clinical standpoint, anti-HCMV therapy could be safely discontinued in 8 patients with HCMV retinitis showing CD4(+) T-cell counts >150/microl, recovery of HCMV LPR, and no HCMV viremia.

CONCLUSIONS

Declining levels of the previously recovered LPR to HCMV are often observed after long-term HAART. However, because the role of LPR in the evolution of HCMV infection and disease during HAART remains to be defined, the clinical impact of the declining LPR to HCMV must still be clarified in long-term prospective studies.

Immune reconstitution in HIV-1-infected individuals treated with potent antiretroviral therapy

Potent combination antiretroviral therapy that was introduced in the mid-1990s for treatment of HIV-1 infection has resulted in unprecedented decreases in HIV-1 replication and increases in CD4+ T cell counts in many individuals. Coincident with the introduction of potent combination antiretroviral therapy, substantial declines in AIDS-related morbidity and mortality have been observed. Although these declines strongly suggest that significant immune reconstitution is occurring, increasing evidence suggests that immune reconstitution is neither uniform nor complete in all treated individuals. Clinical data suggest that some HIV-1-associated malignancies have not declined despite the new therapies, and that not all treated individuals reconstitute CD4+ T cell numbers to normal values. Laboratory studies reveal that immune responses to ubiquitous antigens are reconstituted, but that responses to rarely encountered antigens, such as tetanus, are not reconstituted without repeat vaccination. Many questions remain concerning the extent and clinical significance of the immune reconstitution that occurs in the setting of antiretroviral drug therapy. A better understanding of the nature of the immune reconstitution that results from potent antiretroviral therapy is critical to the optimal clinical management of HIV-1-infected individuals, and may provide important insights into the immunopathogenesis of HIV-1 infection as well.