Immune restoration and CD4+ T-cell function with antiretroviral therapies

Quantification of Oral Candidal Carriage Rate and Prevalence of Oral Candidal Species in HIV Patients with and Without Highly Active Antiretroviral Therapy

BACKGROUND

Most documents review decrease in the prevalence of HIV related oral lesions to the tune of 10-50% following the advent of HAART. However long term use of HAART on oral health status of HIV infected subjects is poorly documented. Also antifungal agents can effectively treat mucosal candidiasis. However their use can lead to colonization with less susceptible strains among normal susceptible strains.

AIMS AND OBJECTIVES

To know the candidal carriage rate (i.e. presence/absence of candidal growth), candidal density(CFUs/ml) & species variations (species diversity) in HIV positive individuals with and without highly active anti-retroviral therapy (HAART), attending the regional voluntary Counselling and Confidential Testing Centre (VCCTC).

MATERIALS AND METHODS

The study population were categorized into 3 groups. Method followed were Germ tube test, Chlamydospore formation test, CHROM-Agar test.

RESULTS

Quantification comparison study of candidal carriage rate, density with detection of various candidal species in the oral cavity of HIV-positive individuals with and without HAART therapy was conducted.

CONCLUSION

HIV positive individuals with HAART therapy treatment prooved higher candidal carriage rate and lower density than Non-HAART category.

The role of CD38 in HIV infection

The widely-expressed molecule CD38 is a single-stranded type II transmembrane glycoprotein that is mainly involved in regulating the differentiation and activation state of the cell. CD38 has broad and complex functions, including enzymatic activity, intercellular signal transduction, cell activation, cytokine production, receptor function and adhesion activity, and it plays an important role in the physiological and pathological processes of many diseases. Many studies have shown that CD38 is related to the occurrence and development of HIV infection, and CD38 may regulate its progression through different mechanisms. Therefore, investigating the role of CD38 in HIV infection and the potential signaling pathways that are involved may provide a new perspective on potential treatments for HIV infection. In the present review, the current understanding of the roles CD38 plays in HIV infection are summarized. In addition, the specific role of CD38 in the process of HIV infection of human CD4⁺ T lymphocytes is also discussed.

Effects of HIV infection and ART on phenotype and function of circulating monocytes, natural killer, and innate lymphoid cells

HIV infection causes upregulation of markers of inflammation, immune activation and apoptosis of host adaptive, and innate immune cells particularly monocytes, natural killer (NK) and innate lymphoid cells (ILCs). Although antiretroviral therapy (ART) restores CD4 T-cell counts, the persistent aberrant activation of monocytes, NK and ILCs observed likely contributes to the incomplete recovery of T-cell effector functions. A better understanding of the effects of HIV infection and ART on the phenotype and function of circulating monocytes, NK, and ILCs is required to guide development of novel therapeutic interventions to optimize immune recovery.

Baseline Naive CD4+ T-cell Level Predicting Immune Reconstitution in Treated HIV-infected Late Presenters

Background:

Among HIV-infected patients initiating antiretroviral therapy (ART), early changes in CD4+ T-cell subsets are well described. However, HIV-infected late presenters initiating treatment present with a suboptimal CD4+ T-cell reconstitution and remain at a higher risk for AIDS and non-AIDS events. Therefore, factors associated with CD4+ T-cell reconstitution need to be determined in this population, which will allow designing effective immunotherapeutic strategies.

Methods:

Thirty-one adult patients with baseline CD4+ T-cell count <350 cells/mm³ exhibiting viral suppression after ART initiation were followed in the HIV/AIDS research center of Peking Union Medical College Hospital in Beijing, China, from October 2002 to September 2013. Changes in T-cell subsets and associated determinants were measured.

Results:

Median baseline CD4+ T-cell count was 70 cells/mm³. We found a biphasic reconstitution of T-cell subsets and immune activation: a rapid change during the first 6 months followed by a more gradual change over the subsequent 8 years. Baseline CD4+ T-cell count >200 cells/mm³ in comparison to CD4+ T-cell count ≤200 cells/mm³ was associated with more complete immune Reconstitution (77.8% vs. 27.3% respectively; P = 0.017) and normalized CD4/CD8 ratio. We showed that the baseline percentage of naive CD4+ T-cell was a predictive marker for complete immune reconstitution (area under receiver operating characteristic curve 0.907), and 12.4% as cutoff value had a sensitivity of 84.6% and a specificity of 88.2%.

Conclusions:

Baseline naive CD4+ T-cell percentage may serve as a predictive marker for optimal immune reconstitution during long-term therapy. Such study findings suggest that increasing thymic output should represent an avenue to improve patients who are diagnosed late in the course of infection.

Delayed reconstitution of B cell immunity to pneumococcus in HIV-infected Malawian children on antiretroviral therapy

OBJECTIVE

Despite CD4(+) count restoration and viral load suppression with antiretroviral therapy (ART), HIV-infected children remain at increased risk of life-threatening infections including invasive pneumococcal disease (IPD). We therefore investigated whether persistent susceptibility to IPD following ART is associated with incomplete recovery of B-cell function.

METHODS

41 HIV-infected Malawian children commencing ART were followed-up for a 1 year period during which time blood samples were collected at 0, 3, 6 and 12 months for comprehensive immunophenotyping and pneumomococcal-specific Memory B-cell Enzyme-Linked Immunospot assays. In addition, nasopharyngeal swab samples were cultured to determine pneumococcal carriage rates.

RESULTS

Normalization of major lymphocyte subsets such as CD4(+) percentages was evident following 3 months of ART. The proportions of mature naïve B cells (CD19(+) CD10(-) CD27(-) CD21(hi)) and resting memory B cells (CD19(+) CD27(+) CD21(hi)) increased and apoptosis-prone mature activated B cells (CD19(+) CD21(lo) CD10(-)) decreased markedly by 12 months. However, in the context of high nasopharyngeal pneumococcal carriage rates (83%), restoration of pneumococcal protein antigen-specific B-cell memory was more delayed.

CONCLUSIONS

These data show that, in chronically HIV-infected children receiving ART, improvement in B-cell memory profiles and function is slower than CD4(+) T-cells. This supports early initiation of ART and informs research into optimal timing of immunization with pneumococcal vaccines.

Low antigen-specific CD4 T-cell immune responses despite normal absolute CD4 counts after long-term antiretroviral therapy an African cohort

BACKGROUND

CD4 counts guide antiretroviral therapy (ART) initiation and prophylaxis for opportunistic infections. It is unclear whether normal CD4 counts translate to normalized immune responses among ART-treated adults. We compared antigen-specific CD4 T-cell immune responses among ART-treated adults with CD4≥500cells/μl, optimal immune responders (O-IR), and their age-matched healthy HIV-negative counterparts.

METHODS

In a sample-based case-control study, cryopreserved peripheral blood mononuclear cells from 15 O-IR after 7 years of ART and 15 healthy controls, were analyzed for CD4+ T-cell proliferation using CFSE dye and cytokine production.

RESULTS

CD4 T-cell proliferation, upon stimulation with PPD and pneumococcal polysaccharide antigen, was lower among O-IR relative to HIV-negative controls; p=0.016 and p=0.016 respectively. CD4 T-cell production of IL-2 was lower among O-IR relative to HIV-negative control p=0.002. CD4 T-cell proliferation upon stimulation with SEB and CMV antigens was similar among O-IR and HIV-negative controls p=0.971 and p=0.480, respectively, and so was IL-4 and IFN γ production; p=0.528 and p=0.892, respectively.

CONCLUSION

Seven years of suppressive ART caused partial CD4 T-cell function recovery in an African HIV treatment cohort, despite restoration of CD4 T-cell counts to levels≥500cells/μl. The role innate immunity in the recovery of immune function during long-term ART should be investigated to guide decisions on continued prophylaxis against opportunistic infections.

Delayed-type hypersensitivity (DTH) test anergy does not impact CD4 reconstitution or normalization of DTH responses during antiretroviral therapy

Introduction

Delayed-type hypersensitivity (DTH) testing is an in vivo assessment of cell-mediated immunity. Although highly active antiretroviral therapy (HAART) improves immunologic parameters, the relationship between DTH responsiveness and CD4 gains on HAART is not completely understood. We investigated CD4 reconstitution and the change in DTH responses from treatment baseline through 24 months of viral load (VL)-suppressive HAART in the U.S. Military HIV Natural History Study.

Methods

Treatment-naïve subjects with VL <400 copies/mL after ≥24 months on HAART were included (n=302). DTH testing consisted of ≥3 recall antigens, and responses were classified by the number of positive skin tests: anergic (0–1) or non-anergic (≥2). Pre-HAART DTH results were compared for the outcome of CD4 reconstitution at 24 months of HAART. Improvement in DTH responses was also analyzed for those anergic before HAART initiation.

Results

Non-anergic responses were observed in 216 (72%) participants, while 86 (28%) individuals were anergic prior to HAART initiation. Demographically there were similar distributions of age at HIV diagnosis and HAART initiation, as well as gender and race or ethnicity. There were no significant differences between non-anergic and anergic participants in pre-HAART CD4 count (409 cells/μL, interquartile range (IQR) 315–517 vs. 373 cells/μL, IQR 228–487; p=0.104) and VL (4.3 log₁₀ copies/mL, IQR 3.4–4.9 vs. 4.4 log₁₀ copies/mL, IQR 3.6–5.0; p=0.292). Median CD4 gains 24 months after HAART initiation were similar between the non-anergic (220 cells/μL, IQR 115–358) and anergic groups (246 cells/μL, IQR 136–358; p=0.498). For individuals anergic before HAART initiation, DTH normalization occurred at 24 months post-HAART in the majority of participants (51 of 86, 59%). Normalization of DTH responses was not associated with CD4 count at HAART initiation (OR 0.73, 95% CI 0.47, 1.09 per 100 cells; p=0.129) nor with AIDS diagnoses prior to HAART (OR 0.34, 95% CI 0.04, 2.51; p=0.283).

Conclusions

DTH responsiveness has been shown to predict HIV disease progression independent of CD4 count in untreated individuals. In the setting of HAART, pre-HAART anergy does not appear to impact CD4 gains or the ability to normalize DTH responses after 24 months of VL-suppressive HAART.

Immune activation and HIV persistence: implications for curative approaches to HIV infection

Despite complete or near-complete suppression of human immunodeficiency virus (HIV) replication with combination antiretroviral therapy, both HIV and chronic inflammation/immune dysfunction persist indefinitely. Untangling the association between the virus and the host immune environment during therapy might lead to novel interventions aimed at either curing the infection or preventing the development of inflammation-associated end-organ disease. Chronic inflammation and immune dysfunction might lead to HIV persistence by causing virus production, generating new target cells, enabling infecting of activated and resting target cells, altering the migration patterns of susceptible target cells, increasing the proliferation of infected cells, and preventing normal HIV-specific clearance mechanisms from function. Chronic HIV production or replication might contribute to persistent inflammation and immune dysfunction. The rapidly evolving data on these issues strongly suggest that a vicious cycle might exist in which HIV persistence causes inflammation that in turn contributes to HIV persistence.

Paclitaxel for AIDS-associated Kaposi’s sarcoma

Treatment options are limited for patients with advanced acquired immunodeficiency syndrome-related Kaposi's sarcoma (AIDS-KS). The management of early stage cutaneous AIDS-KS has been revolutionized by the introduction of highly active antiretroviral therapy and for most patients highly active antiretroviral therapy alone will control early stage AIDS-KS. However, patients with advanced stage Kaposi's sarcoma with visceral disease, tumor-associated edema or extensive oral disease require systemic chemotherapy in addition to antiretrovirals. The standard first-line therapy for these affected individuals is a liposomal anthracycline, and response rates of around 70% are usually achieved. For patients with refractory or recurrent AIDS-KS, treatment algorithms are less well defined. The use of paclitaxel in these circumstances is reviewed.

Poor immunological recovery among severely immunosuppressed antiretroviral therapy-naïve Ugandans

Introduction

CD4 T lymphocytes remain the surrogate measure for monitoring HIV progress in resource-limited settings. The absolute CD4 cell counts form the basis for antiretroviral therapy (ART) initiation and monitoring among HIV-infected adults. However, the rate of CD4 cell change differs among patients, and the factors responsible are inadequately documented.

Objective

This study investigated the relationship between HIV severity and ART outcomes among ART-naïve Ugandans, with the primary outcome of complete immunological recovery among patients of different baseline CD4 counts.

Methods

Patients’ records at two HIV/ART sites – the Joint Clinic Research Centre (JCRC) in the Kampala region and Mbarara Hospital in Western Uganda – were reviewed. Records of 426 patients – 68.3% female and 63.2% from JCRC – who initiated ART between 2002 and 2007 were included. HIV severity was based on baseline CD4 cell counts, with low counts considered as severe immunosuppression, while attaining 418 CD4 cells/μL signified complete immunological recovery. Incidence rates of complete immunological recovery were calculated for, and compared between baseline CD4 cell categories: <50 with ≥50, <100 with ≥100, <200 with ≥200, and ≥200 with ≥250 cells/μL.

Results

The incidence of complete immunological recovery was 158 during 791.9 person-years of observation, and patients with baseline CD4 ≥ 200 cells/μL reached the end point of immunological recovery 1.89 times faster than the patients with baseline CD4 < 200 cells/μL. CD4 cell change also differed by time, sex, and site, with a faster increase observed during the first year of treatment. CD4 cell increase was faster among females, and among patients from Mbarara.

Conclusion

Initiating ART at an advanced HIV stage was the main reason for poor immunological recovery among Ugandans. Earlier ART initiation might lead to better immunological responses.

Depression of local cell-mediated immunity and histological characteristics of disseminated AIDS-related Mycobacterium avium infection after the initiation of antiretroviral therapy

OBJECTIVE

The aim of the present study was to examine the immunohistological characteristics of disseminated Mycobacterium avium infection after the initiation of antiretroviral therapy (ART) for acquired immunodeficiency syndrome (AIDS).

METHODS

We histologically investigated five autopsied AIDS patients with systemic M. avium infection.

RESULTS

The inflammatory cell composition in the affected tissues was assessed using immunohistochemistry. The celiac lymph nodes and intestinal canal were the most commonly involved organs in the AIDS cases. The most common histological feature was unstructured aggregation of histiocytes. Immunohistochemistry revealed depression of CD4(+), CD8(+) and CD57(+) cells in the gut lamina propria and mesenteric lymph nodes.

CONCLUSION

These findings suggest that local cell-mediated immunity is depressed in affected tissues and that the primary histological feature is poor organization of granulomas in mycobacterial lesions, despite the administration of adequate ART.

Frequency of circulating regulatory T cells increases during chronic HIV infection and is largely controlled by highly active antiretroviral therapy

Regulatory T cells (Tregs) act by suppressing the activation and effector functions of innate and adaptive immune responses. HIV infection impacts Treg proportion and phenotype, although discrepant results have been reported depending on the patient population and the way Tregs were characterized. The effects of highly active antiretroviral therapy (HAART) on Treg frequency have not been thoroughly documented. We performed a detailed longitudinal analysis of Treg frequency and phenotype in 11 HIV-infected individuals enrolled in a single, prospective clinical trial, in which all patients underwent the same treatment protocol and were sampled at the same time points. Tregs were characterized for their expression of molecules associated with activation, cell cycle, apoptosis, or function, and compared to circulating Tregs from a group of age-matched healthy individuals.

Our results revealed increased proportions, but reduced absolute numbers of circulating CD3⁺CD4⁺FOXP3⁺ Tregs in chronically infected HIV-infected patients. Treg frequency was largely normalized by HAART. Importantly, we show that similar conclusions were drawn regardless of the combination of markers used to define Tregs. Our results also showed increased expression of cell cycle markers (Ki67 and cyclin B) in Tregs from untreated infected individuals, which were decreased by HAART. However, the Treg phenotype in untreated patients was not consistent with a higher level of generalized activation, as they expressed very low levels of CD69, slightly elevated levels of HLA-DR and similar levels of GARP compared to Tregs from uninfected donors. Moreover, none of these markers was significantly changed by HAART. Treg expression of CTLA-4 and cytotoxic molecules was identical between patients and controls. The most striking difference in terms of functional molecules was the high expression of CD39 by Tregs in untreated patients, which HAART only partially controlled.

[Modeling of antiretroviral response from taxonomy of CD4 cells count trajectories in profound immunodeficiency setting]

Modeling of CD4 cells counts response was performed through a Non-Hierarchical-descendant process with profoundly immunocompromised symptomatic patients under nevirapine or efavirenz-based antiretroviral regimen in Abidjan. Similar CD4 cells count trajectories have been modelled in meta-trajectories linked to patients' classes. Global immunological response is similar between "nevirapine group" and "efavirenz group" but the model showed an internal variation of this response in each group. In the both groups, some variables presented a significant variation between classes: average CD4, CD4 Nadir, CD4 peak and average gain of CD4. In "nevirapine group", these following parameters vary significantly between classes: mean weight, mean haemoglobin count and mean increase in haemoglobin count and sex. It's also important to note that, all meta-trajectories began with distinctive categories of baseline CD4 cells counts. Other explanatory factors must be sought because the characteristics we have chosen to describe patients'classes, are not exhaustive.

Síndrome de restauração imune associada à histoplasmose

Paciente masculino, 27 anos, portador de HIV, com quadro de histoplasmose cutânea disseminada. Terapia antirretroviral oral e anfotericina B por via EV (dose total acumulada 0,5g) foram introduzidas, verificando-se rápida cicatrização das lesões após duas semanas. A anfotericina B foi substituída por itraconazol (200mg/dia). O paciente interrompeu voluntariamente os tratamentos. A terapia antirretroviral foi reintroduzida, havendo aumento da contagem de células T CD4-positivas (No restante do texto, a autora usa o símbolo "+" (T CD4+) ao invés da palavra "positiva". O que fazer neste caso? Seguimos o padrão do restante do texto ou acatamos essa opção da autora no resumo?!). Neste momento, diagnosticou-se histoplasmose ganglionar. O aumento da contagem de células T CD4-positivas (de novo aqui), associado à redução da carga viral a níveis inferiores ao limite de detecção após a reintrodução da terapia antirretroviral, sugere que essa piora clínica paradoxal seja uma síndrome de restauração imune

Surgical crown lengthening in a population with human immunodeficiency virus: a retrospective analysis)

BACKGROUND

Individuals with human immunodeficiency virus (HIV) have an increased risk of developing health problems, including some that are life threatening. Today, dental treatment for the population with a positive HIV diagnosis (HIV+) is comprehensive. There are limited reports on the outcomes of intraoral surgical therapy in patients with HIV, such as crown lengthening surgery (CLS) with osseous recontouring. This report investigates the outcome of CLS procedures performed at an urban dental school in a population of individuals with HIV. Specifically, this retrospective clinical analysis evaluates the healing response after CLS.

METHODS

Paper and electronic records were examined from the year 2000 to the present. Twenty-one individuals with HIV and immunosuppression, ranging from insignificant to severe, underwent CLS. Pertinent details, including laboratory values, medications, smoking history/status, and postoperative outcomes, were recorded. One such surgery is described in detail with radiographs, photographs, and a videoclip.

RESULTS

Of the 21 patients with HIV examined after CLS, none had postoperative complications, such as delayed healing, infection, or prolonged bleeding. Variations in viral load (<48 to 40,000 copies/mL), CD4 cell count (126 to 1,260 cells/mm(3)), smoking (6 of 21 patients), platelets (130,000 to 369,000 cells/mm(3)), and neutrophils (1.1 to 4.5 × 103 /mm(3)) did not impact surgical healing. In addition, variations in medication regimens (highly active anti-retroviral therapy [18]; on protease inhibitors [1]; no medications [2]) did not have an impact.

CONCLUSIONS

The results of this retrospective analysis show the absence of postoperative complications after CLS in this population with HIV. Additional investigation into this area will help health care practitioners increase the range of surgical services provided to this group of patients.

Impact of the immune reconstitution inflammatory syndrome (IRIS) on mortality and morbidity in HIV-infected patients in Mexico

OBJECTIVES

To estimate the impact of immune reconstitution inflammatory syndrome (IRIS) on morbidity and mortality in patients starting highly-active antiretroviral therapy (HAART).

METHODS

A retrospective cohort study of HIV-positive patients starting HAART was conducted at a tertiary care referral center in Mexico City. We estimated the incidence of IRIS, hospitalizations and death rates during the first 2 years of HAART. The relative risk of death (RR) and hospitalization for patients with IRIS were adjusted for relevant covariates using regression methods.

RESULTS

During the 2-year follow-up period, 27% of patients developed IRIS (14 IRIS cases per 100 person-years). The relative risk of death among patients who developed IRIS was 3 times higher (95% confidence interval (CI) 1.19-7.65, p = 0.03). After adjusting for previous opportunistic infections we still observed a higher death rate among patients with IRIS (RR 2.3, 95% CI 0.9-5.9, p=0.09). An effect modification of IRIS over mortality was observed by previous opportunistic infection.

CONCLUSIONS

IRIS-associated mortality is strongly confounded by previous opportunistic infection. Patients with AIDS who eventually developed IRIS had the highest risk of death at the 2-year follow-up.

Clinical Markers of Immunodeficiency and Mechanism of Immune Reconstitution Inflammatory Syndrome and Highly Active Antiretroviral Therapy on HIV

Antiretroviral therapy (ART) has improved survival and changed the disease pattern of HIV infection. However, ART may cause serious side effects, such as metabolic and cardiovascular complications. In addition, immune reconstitution inflammatory syndrome (IRIS) is being increasingly reported in relation to ART. The article presents the consensus of a workshop around 4 key issues: (1) the differences in the response of adults and children to highly active antiretroviral therapy, (2) the mechanism of the new HIV entry inhibitors and its effect on oral markers, (3) the pathogenesis of IRIS and the contradictory findings of the possible oral lesions related with IRIS, (4) and the benefits and barriers associated with using ART in the developing and developed world. The consensus of the workshop was that there is a need for future studies on the oral manifestations of HIV in individuals treated with new ARTs—especially, children. IRIS was considered a promising field for future research; as such, workshop attendees recommended formulating an IRIS–oral lesions case definition and following strict criteria for its diagnosis.

In vitro naïve T cell proliferation failure predicts poor post-immunization responses to neoantigen, but not recall antigens, in HIV-infection

Immune reconstitution after HAART is incomplete, but no widely accepted method to quantify subclinical immune deficiency is available. We immunized 9 HIV-negative subjects and 29 HIV-infected patients with CD4>/=450 cells/microL and undetectable HIV RNA levels with 2 doses of diphtheria/tetanus toxoid (TT) and KLH, a presumed neoantigen. We quantified the response by lymphoproliferative assay, delayed-type hypersensitivity (DTH), and antibody titers up to 59days after enrollment. We assessed T cell proliferative capacity using anti-Vbeta3 and anti-Vbeta5 antibody stimulation, which we herein show induced predominant proliferation of naïve T cells. Subjects with detectable responses to KLH tended to exhibit greater proliferative responses to anti-Vbeta3/Vbeta5 stimulation; no such pattern was seen with response to TT. Several measures of in vitro T cell proliferative capacity correlated significantly with DTH and antibody responses to KLH, but not with TT responses; this association was independent of naïve T cell numbers. Our results indicate that naïve T cell proliferation predicts response to neo-, but not recall antigens, and suggest that it may be a meaningful reflection of in vivo immune competence in HIV-infected persons.

Impact of gamma-chain cytokines on T cell homeostasis in HIV-1 infection: therapeutic implications

CD4(+) T cell lymphocytes are a major target for human immunodeficiency virus type-1 (HIV-1) infection. During this chronic infection, CD4(+) T cell loss (induced through direct viral replication), generalized immune activation and increased susceptibility to apoptosis result in impaired T cell homeostasis with subsequent development of opportunistic infections and cancers. Highly active antiretroviral therapy (HAART) has a well-defined, beneficial effect on HIV-1-related clinical outcome; however, it does not lead to normalization of immune dysregulation. In order to boost both CD4(+) T cell restoration and HIV-1 specific immunity, immunotherapy with gamma-chain cytokines has been used in HIV-1-infected patients during concomitant HAART. In this review, we summarize the role of gamma-chain cytokines, especially interleukin (IL)-2 and IL-7, in influencing T cell homeostasis and proliferation, and discuss how immunotherapy with these cytokines may be beneficial to reconstitute the T cell compartment in the context of HIV-1 infection. The intriguing results of two large trials evaluating the efficacy of IL-2 in restoring immune function during HIV-1 infection are also discussed. In addition, we consider the promises and caveats of the first phase I/II clinical trials with IL-7 in HIV-1-infected patients and the knowledge that is still lacking in the field of T cell reconstitution through gamma-chain cytokines.

Effects of long-term use of HAART on oral health status of HIV-infected subjects

BACKGROUND

The aim of this study was to determine the effects of long-term use of highly active antiretroviral therapy (HAART) on oral health status of HIV-infected subjects.

METHODS

Oral examination and measurement of saliva flow rate of both unstimulated and wax-stimulated whole saliva were performed in HIV-infected subjects with and without HAART, and in non-HIV individuals. The following data were recorded; duration and risk of HIV infection, type and duration of HAART, CD4 cell count, viral load, presence of orofacial pain, oral dryness, oral burning sensation, oral lesions, cervical caries, and periodontal pocket. Multiple logistic regression analysis was performed to determine the effects of long-term use of HAART on oral health status of HIV-infected subjects.

RESULTS

One hundred and fifty-seven HIV-infected subjects - 99 on HAART (age range 23-57 years, mean 39 years) and 58 not on HAART (age range 20-59 years, mean 34 years) - and 50 non-HIV controls (age range 19-59 years, mean 36 years) were enrolled. The most common HAART regimen was 2 NRTI + 2 NNRTI. HIV-infected subjects without HAART showed greater risks of having orofacial pain, oral dryness, oral lesions, and periodontal pockets than those with short-term HAART (P < 0.01). The subjects with long-term HAART were found to have a greater risk of having oral lesions than those with short-term HAART (P < 0.05). The unstimulated and stimulated salivary flow rates of the subjects with HAART were significantly lower than in those without HAART (P < 0.05).

CONCLUSION

We conclude that long-term HAART has adverse effects on oral health status of HIV-infected subjects.

Tuberculosis-associated immune reconstitution inflammatory syndrome and unmasking of tuberculosis by antiretroviral therapy

The tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a frequent early complication of antiretroviral therapy (ART), used to treat HIV-1 infection, especially in countries where TB is prevalent. TB-IRIS is characterized by an exaggerated inflammatory response toward the antigens of Mycobacterium tuberculosis that results in clinical deterioration in patients experiencing immune recovery during early ART. Two forms of TB-IRIS are recognized: paradoxical; and unmasking. Paradoxical TB-IRIS manifests with new or recurrent TB symptoms or signs in patients being treated for TB during early ART, and unmasking TB-IRIS is characterized by an exaggerated, unusually inflammatory initial presentation of TB during early ART. In this review the incidence, clinical features, risk factors, treatment, and prevention of TB-IRIS in adult and pediatric patients are discussed.

Pneumocystis-associated organizing pneumonia as a manifestation of immune reconstitution inflammatory syndrome in an HIV-infected individual with a normal CD4+ T-cell count following antiretroviral therapy

We describe a rare case of Pneumocystic jirovecii-associated organizing pneumonia (PJP) in an HIV-infected individual on highly active antiretroviral therapy (HAART) with a CD4(+) T-cell count of 835 x 10(3) cells/mL and a low viral load. PJP was confirmed using transbronchial biopsies and bronchoalveolar lavage. The presentation in this patient suggests immune reconstitution inflammatory syndrome (IRIS) after institution of antiretroviral therapy (ART). This case report, however, is the first documented presentation of PJP in a patient with CD4 count greater than 300 prior to the induction of HAART who developed PJP and organizing pneumonia as a manifestation of IRIS. This suggests that there is continuing immune dysfunction in the face of re-expansion of CD4(+) T-cells and low viral load in HIV patients despite ART.

A brief review of potential mechanisms of immune reconstitution inflammatory syndrome in HIV following antiretroviral therapy

A subset of HIV-infected individuals who receive antiretroviral therapy (ART) develop a paradoxical pathological response that significantly increases morbidity and sometimes mortality. Following the induction of highly active ART, a rapid decline in the viral load results within weeks and coincides with a steep rise in the CD4(+) T-cell counts and immune hyperactivation. Although no mechanistic pathway has been elucidated for the development of immune reconstitution inflammatory syndrome (IRIS), it is thought that change in the nature of the immune response is a predominant factor in the development of reconstitution disease. In this article, we review the current state of knowledge in this field and provide a model for the development of IRIS.

B cells in HIV infection and disease

In recent years, intense research efforts have been dedicated to elucidating the pathogenic mechanisms of HIV-associated disease progression. In addition to the progressive depletion and dysfunction of CD4(+) T cells, HIV infection also leads to extensive defects in the humoral arm of the immune system. The lack of immune control of the virus in almost all infected individuals is a great impediment to the treatment of HIV-associated disease and to the development of a successful HIV vaccine. This Review focuses on advances in our understanding of the mechanisms of B-cell dysfunction in HIV-associated disease and discusses similarities with other diseases that are associated with B-cell dysfunction.

Unmasked tuberculosis and tuberculosis immune reconstitution inflammatory disease: a disease spectrum after initiation of antiretroviral therapy

Antiretroviral therapy (ART) has beneficial effects on mortality and lowers the incidence of diseases caused by opportunistic infections, such as tuberculosis (TB). Although ART has sustained long-term benefits, the risk of TB is high during the first 3 months after ART initiation. Among cases of ART-associated TB, we define "unmasked TB" as that which occurs in patients with reactivation disease who develop clinically recognizable TB after ART with the restoration of previously acquired TB antigen-specific functional immune responses. TB cases with clinical evidence of an inflammatory syndrome are a subset of these unmasked cases, which we define as "unmasked TB-immune reconstitution inflammatory syndrome." With more widespread use of ART in areas with a high prevalence of TB, unmasked TB will likely become more common. TB diagnostics with improved sensitivity and specificity are urgently needed to detect subclinical TB before it is unmasked.

Incomplete reconstitution of T cell subsets on combination antiretroviral therapy in the AIDS Clinical Trials Group protocol 384

BACKGROUND

Initiation of combination antiretroviral therapy (ART) results in higher total CD4 cell counts, a surrogate for immune reconstitution. Whether the baseline CD4 cell count affects reconstitution of immune cell subsets has not been well characterized.

METHODS

Using data from 978 patients (621 with comprehensive immunological assessments) from the AIDS [Acquired Immunodeficiency Syndrome] Clinical Trials Group protocol 384, a randomized trial of initial ART, we compared reconstitution of CD4(+), CD4(+) naive and memory, CD4(+) activation, CD8(+), CD8(+) activation, B, and natural killer cells among patients in different baseline CD4(+) strata. Reference ranges for T cell populations in control patients negative for human immunodeficiency virus (HIV) infection were calculated using data from AIDS Clinical Trials Group protocol A5113.

RESULTS

Patients in the lower baseline CD4(+) strata did not achieve total CD4(+) cell counts similar to those of patients in the higher strata during 144 weeks of ART, although CD4(+) cell count increases were similar. Ratios of CD4(+) naive-memory cell counts and CD4(+):CD8(+) cell counts remained significantly reduced in patients with lower baseline CD4(+) cell counts (

CONCLUSIONS

After nearly 3 years of ART, T cell subsets in patients with baseline CD4(+) cell counts >350 cells/mm(3) achieved or approached the reference range those of control individuals without HIV infection. In contrast, patients who began ART with Collapse

Key Words Collapse

MESH Headings

• Acquired Immunodeficiency Syndrome/drug therapy
• Acquired Immunodeficiency Syndrome/immunology
• Adult
• Antiretroviral Therapy, Highly Active
• B-Lymphocytes/immunology
• CD4 Lymphocyte Count
• CD4-CD8 Ratio
• Female
• Humans
• Killer Cells, Natural/immunology
• Male
• Middle Aged
• T-Lymphocyte Subsets/immunology

Collapse

Grants

• AI25879 NIAID NIH HHS
• AI066992 NIAID NIH HHS
• K01 AI062435-02 NIAID NIH HHS
• R01 AI066992 NIAID NIH HHS
• U01 AI038858 NIAID NIH HHS
• AI27659 NIAID NIH HHS
• AI38855 NIAID NIH HHS
• IP30AI060354 NIAID NIH HHS
• U01 AI025879 NIAID NIH HHS
• K01 AI062435 NIAID NIH HHS
• AI27666 NIAID NIH HHS
• AI38858 NIAID NIH HHS
• K01 AI062435-04 NIAID NIH HHS
• U01 AI038855 NIAID NIH HHS
• K01 AI062435-03 NIAID NIH HHS
• K01AI062435 NIAID NIH HHS
• U01 AI027666 NIAID NIH HHS
• K01 AI062435-01A1 NIAID NIH HHS
• U01 AI027659 NIAID NIH HHS
• P30 AI060354 NIAID NIH HHS

Collapse

Affiliation(s)

Gregory K Robbins Infectious Diseases Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
John G Spritzler
Ellen S Chan
David M Asmuth
Rajesh T Gandhi
Benigno A Rodriguez
Gail Skowron
Paul R Skolnik
Robert W Shafer
Richard B Pollard

Collapse

Immune reconstitution inflammatory syndrome in HIV-infected patients receiving antiretroviral therapy : pathogenesis, clinical manifestations and management

The use of antiretroviral therapy (ART) to treat HIV infection, by restoring CD4+ cell count and immune function, is associated with significant reductions in morbidity and mortality. Soon after ART initiation, there is a rapid phase of restoration of pathogen-specific immunity. In certain patients, this results in inflammatory responses that may result in clinical deterioration known as 'the immune reconstitution inflammatory syndrome' (IRIS). IRIS may be targeted at viable infective antigens, dead or dying infective antigens, host antigens, tumour antigens and other antigens, giving rise to a heterogeneous range of clinical manifestations. The commonest forms of IRIS are associated with mycobacterial infections, fungi and herpes viruses. In most patients, ART should be continued and treatment for the associated condition optimized, and there is anecdotal evidence for the use of corticosteroids in patients who are severely affected. In this review, we discuss research relating to pathogenesis, the range of clinical manifestations, treatment options and prevention issues.

[Immune reconstitution inflammatory syndrome (IRIS)]

Overwhelming immune reaction resulting in granulomatous inflammation after infection with opportunistic pathogens has been termed immune reconstitution inflammatory syndrome (IRIS). IRIS has mainly been described in patients with human immunodeficiency virus (HIV). However, IRIS is not restricted to HIV-patients and may occur in other infections and immunodeficiencies. In our clinic, we experienced a Whipple's disease patient with IRIS. IRIS occurs mainly after initiation of the highly active anti-retroviral therapy (HAART). Soon after HAART initiation, a marked inflammatory reaction can occur, triggered by restoration of pathogen-specific immunity. IRIS may be targeted by various infective antigens, dead or dying infective antigens, host antigens, tumor antigens and other antigens, giving rise to a heterogenous range of clinical manifestations. Treatment should be optimized for the associated condition and initiated immediately. Glucocorticoids should be used in patients who are severely affected by IRIS.

Insights into pathogenic events of HIV-associated Kaposi sarcoma and immune reconstitution syndrome related Kaposi sarcoma

A decrease in the incidence of human immune deficiency virus-associated Kaposi sarcoma (HIV-KS) and regression of some established HIV-KS lesions is evident after the introduction of highly active anti-retroviral treatment (HAART), and is attributed to generalized immune restoration, to the reconstitution of human herpesvirus (HHV)-8 specific cellular immune responses, and to the decrease in HIV Tat protein and HHV-8 loads following HAART. However, a small subset of HIV-seropositive subjects with a low CD4+ T cell count at the time of introduction of HAART, may develop HIV-KS as immune reconstitution inflammatory syndrome (IRIS) within 8 weeks thereafter.

Rapid modifications of peripheral T-cell subsets that express CD127 in macaques treated with recombinant IL-7

BACKGROUND

Interleukin-7 (IL-7) is a key regulator of thymopoiesis and T-cell homeostasis, which increases blood T-cell number by enhancing thymic output of naive cells and peripheral proliferation.

METHODS

We explored the effects of unglycosylated recombinant simian IL-7 (rsIL-7) administration on peripheral T-cell subpopulations in healthy macaques.

RESULTS

RsIL-7 was well tolerated. Mean half-life ranged between 9.3 and 13.9 hours. Blood CD3(+)CD4(+) and CD3(+)CD8(+) lymphocyte counts decreased rapidly after each rsIL-7 administration, the duration of these effects being dependent on the frequency of administration. At treatment completion, the increased of CD3(+) lymphocytes was marked at 100 microg/kg every 2 days. CD3(+) lymphocytes that harbour the alpha chain of IL-7 receptor (CD127) and CD3(+)CD8(+) lymphocytes that expressed the proliferation marker Ki-67 exhibited a similar initial profile. The expression of the anti-apoptotic marker Bcl-2 increased in CD3(+) lymphocytes during the treatment and post-treatment period in a dose/frequency dependent manner.

CONCLUSION

RsIL-7 was well tolerated in macaques and induces rapid modifications of T-cells that express CD127.

Incidence and risk factors of major opportunistic infections after initiation of antiretroviral therapy among advanced HIV-infected patients in a resource-limited setting

OBJECTIVE

To study incidence, risk factors, and impact of major opportunistic infections (OIs) after initiation of antiretroviral therapy (ART).

METHODS

A retrospective cohort study was conducted among naïve HIV-infected patients who were initiated ART during January 2003-December 2004. All patients were followed until 15 months after ART.

RESULTS

There were 793 patients with mean+/-SD age of 35.2+/-7.4 years and 56.3% male. Median (IQR) CD4 was 26 (9-78) cells/mm3. Of 793 patients, 61 (8%) patients developed 81 episodes of OIs after ART. These included tuberculosis (48.1%), CMV retinitis (19.8%), MAC infection (14.8%), PCP (9.9%), cryptococcosis (6.2%) and penicilliosis (1.2%). Overall incidence of new episode of OIs after ART was 8.0% during the first year of ART. Probabilities of OIs at 1, 2, 3, 6, and 12 months after ART were 2.6%, 4.0%, 5.3%, 6.9% and 8.0%, respectively. Baseline CD4 < or = 50 cells/mm3, male gender, and low body weight were associated with higher incidence of OIs after ART (P<0.05).

CONCLUSIONS

Most of new episodes of major OIs develop within the first three months after ART. Tuberculosis is the most frequent OIs in this situation. The substantial increase of new episode of OIs after ART was observed among HIV-infected patients with CD4 cell counts < or = 50 cells/mm3 at ART initiation.

Immunological response to hepatitis B vaccination in patients with AIDS and virological response to highly active antiretroviral therapy

Previous studies showed that an immunological response to hepatitis B virus (HBV) vaccination in patients with AIDS was lower than in the normal population. However, those with virological response to highly active antiretroviral therapy (HAART) may have a normal immunological response to HBV vaccination. In our study, patients with AIDS who had a virological response to HAART and no immunity to HBV received 3 doses of HBV vaccine (20 microg of Engerix-B(R)) on d 0, 30, and 180. Anti-HBs level was measured 1 month after complete vaccination. Of 28 patients, overall response rate to vaccination was 71.4%. The responder group had a significantly higher CD4 count at 1 month after complete vaccination than the non-responder group (466.95+/-146.94 and 335+/-112.62 cells/microl, p =0.035). The patients receiving efavirenz-containing HAART had better response than those without efavirenz-containing HAART (p =0.030). The responder group had received a longer duration of HAART. In conclusion , to our knowledge, ours is the first prospective study to determine the immunological response to HBV vaccination in all patients with AIDS who had maintained the virological response after receiving HAART throughout the study period. Patients with AIDS and virological response to HAART have a good immunological response to HBV vaccination.

Pretreatment Factors Associated With 3-Year (144-Week) Virologic and Immunologic Responses to Potent Antiretroviral Therapy

OBJECTIVE

To examine pretreatment factors associated with longer term (144 weeks) responses to antiretroviral therapy (ART).

METHODS

Of 1498 ART-naive subjects randomized to ART regimens, including > or =3 agents, 1083 patients who had plasma HIV RNA (vRNA) levels and CD4 cell counts at baseline and week 144 were analyzed. Primary baseline factors evaluated were CD4 cell count, vRNA level, gender, race, and age, using multivariable Cox, log-binomial, and linear regression models.

RESULTS

Shorter time to achieving a vRNA level <50 copies/mL was associated with lower baseline vRNA level (P < 0.001), older age (P = 0.007), and lower baseline CD4 cell count (P = 0.055). After adjusting for race, gender, and baseline CD4 cell count, older age was associated with a vRNA level <50 copies/mL at week 144 (P = 0.018). Greater CD4 count increases from baseline to week 144 (mean = 284 cells/microL) were seen in younger men, blacks, and subjects with higher pretreatment vRNA levels; the effect of pretreatment vRNA level was most apparent in women.

CONCLUSIONS

Older age was the most important baseline predictor of a vRNA level <50 copies/mL at week 144; lower pretreatment vRNA level and older age were the most important predictors of time to a vRNA level <50 copies/mL. The influence of pretreatment factors on increases in CD4 cell counts differed between men and women.

Immune reconstitution disease associated with parasitic infections following antiretroviral treatment

HIV-associated immune reconstitution disease (IRD) is the clinical presentation or deterioration of opportunistic infections that results from enhancement of pathogen-specific immune responses among patients responding to antiretroviral treatment (ART). The vast majority of reported cases of IRD have been associated with mycobacterial, chronic viral and invasive fungal infections; such cases result from dysregulated augmentation of cell-mediated type 1 cytokine-secreting host immune responses. However, the spectrum of infections now recognized as associated with IRD is expanding and includes a number of parasitic infections, which may be mediated by different immunopathological mechanisms. These include leishmaniasis (visceral, cutaneous, mucosal and post kala azar dermal leishmaniasis), schistosomiasis and strongyloidiasis. Since the major burden of HIV lies in resource-limited countries where access to ART is now rapidly expanding, increased awareness and knowledge of these phenomena is important. Here we review the clinical spectrum and pathogenesis of IRD associated with parasitic infections.

Dermatologic Manifestations of the Immune Reconstitution Inflammatory Syndrome

The immune reconstitution inflammatory syndrome (IRIS) represents a diverse range of immunopathologic reactions resulting in clinical deterioration that may occur as immune function is partially restored in HIV-infected patients receiving highly active antiretroviral therapy. Approximately half of IRIS events are dermatologic, and dermatologic IRIS is described in relation to a wide range of conditions, the commonest being herpes zoster and herpes simplex. Most cases of IRIS result in mild and moderate symptoms, but non-dermatologic manifestations related to IRIS have resulted in death. This article covers certain general issues related to IRIS and then focuses on the spectrum of dermatologic manifestations.

Viral suppression and immune restoration in the gastrointestinal mucosa of human immunodeficiency virus type 1-infected patients initiating therapy during primary or chronic infection

Although the gut-associated lymphoid tissue (GALT) is an important early site for human immunodeficiency virus (HIV) replication and severe CD4+ T-cell depletion, our understanding is limited about the restoration of the gut mucosal immune system during highly active antiretroviral therapy (HAART). We evaluated the kinetics of viral suppression, CD4+ T-cell restoration, gene expression, and HIV-specific CD8+ T-cell responses in longitudinal gastrointestinal biopsy and peripheral blood samples from patients initiating HAART during primary HIV infection (PHI) or chronic HIV infection (CHI) using flow cytometry, real-time PCR, and DNA microarray analysis. Viral suppression was more effective in GALT of PHI patients than CHI patients during HAART. Mucosal CD4+ T-cell restoration was delayed compared to peripheral blood and independent of the time of HAART initiation. Immunophenotypic analysis showed that repopulating mucosal CD4+ T cells were predominantly of a memory phenotype and expressed CD11 alpha, alpha(E)beta 7, CCR5, and CXCR4. Incomplete suppression of viral replication in GALT during HAART correlated with increased HIV-specific CD8+ T-cell responses. DNA microarray analysis revealed that genes involved in inflammation and cell activation were up regulated in patients who did not replenish mucosal CD4+ T cells efficiently, while expression of genes involved in growth and repair was increased in patients with efficient mucosal CD4+ T-cell restoration. Our findings suggest that the discordance in CD4+ T-cell restoration between GALT and peripheral blood during therapy can be attributed to the incomplete viral suppression and increased immune activation and inflammation that may prevent restoration of CD4+ T cells and the gut microenvironment.

Optimization of in vitro expansion of macaque CD4 T cells using anti-CD3 and co-stimulation for autotransfusion therapy

BACKGROUND

Our laboratory has previously shown that adoptive transfer of in vitro-expanded autologous purified polyclonal CD4(+) T cells using anti-CD3/CD28-coated beads induced antiviral responses capable of controlling SIV replication in vivo.

METHODS

As CD4(+) T cells comprise several phenotypic and functional lineages, studies were carried out to optimize the in vitro culture conditions for maximal CD4(+) T-cell expansion, survival and delineate the phenotype of these expanded CD4(+) T cells to be linked to maximal clinical benefit.

RESULTS AND CONCLUSIONS

The results showed that whereas anti-monkey CD3gamma/epsilon was able to induce T-cell proliferation and expansion in combination with antibodies against multiple co-stimulatory molecules, monkey CD3epsilon cross reacting antibodies failed to induce proliferation of macaque CD4(+) T cells. Among co-stimulatory signals, anti-CD28 stimulation was consistently superior to anti-4-1BB, CD27 or ICOS while the use of anti-CD154 failed to deliver a detectable proliferation signal. Increasing the relative anti-CD28 co-stimulatory signal relative to anti-CD3 provided a modest enhancement of expansion. Additional strategies for optimization included attempts to neutralize free radicals, enhancement of glucose uptake by T cells or addition of T-cell stimulatory cytokines. However, none of these strategies provided any detectable proliferative advantage. Addition of 10 autologous irradiated feeder cells/expanding T cell provided some enhancement of expansion; however, given the high numbers of T cell needed, this approach was deemed impractical and costly, and lower ratios of feeder to expanding T cells failed to provide such benefit. The most critical parameter for efficient expansion of purified CD4(+) T cells from multiple monkeys was the optimization of space and culture conditions at culture inception. Finally, anti-CD3/28-expanded CD4(+) T cells uniformly exhibited a central memory phenotype, absence of CCR5 expression, marked CXCR4 expression in vitro, low levels of caspase 3 but also of Bcl-2 expression.

Immune reconstitution syndrome from nontuberculous mycobacterial infection after initiation of antiretroviral therapy in children with HIV infection

The immune reconstitution syndrome caused by nontuberculous mycobacterial (NTM) infection is reported in 9 of 153 HIV-infected children 2 to 26 weeks after initiation of antiretroviral therapy. The clinical syndrome included fever and dyspnea (2 children), fever and abdominal pain (3), subcutaneous nodules or suppurative lymphadenitis (4). The causative species were Mycobacterium avium (4), Mycobacterium scrofulaceum (3), Mycobacterium kansasii (1) and Mycobacterium simiae (1).

DNA immunization in combination with effective antiretroviral drug therapy controls viral rebound and prevents simian AIDS after treatment is discontinued

DNA immunization in conjunction with antiretroviral therapy was evaluated in SIV-infected rhesus macaques treated with [R]-9-[2-phosphonylmethoxypropyl]adenine (PMPA). Macaques were immunized monthly with DNA vaccines expressing either SIV gag/tat or SIV gag/tat and 19 CD8+ T cell epitopes during 7 months of therapy. Half the animals from each group were additionally immunized before infection. Only 60% of the animals (4 controls, 20 vaccinated) responded to PMPA (ART responders). All 4 ART responder controls demonstrated viral rebound or CD4 decline after PMPA was withdrawn. In contrast, 17 of 20 vaccinated ART responders contained viral rebound for over 7 months after PMPA was withdrawn. Viral control correlated with stable CD4 counts, higher lymphoproliferation and an increase in the magnitude and breadth of the CD8+ T cell response. Immunizing before infection or with multi-epitopes enhanced these effects. These results demonstrate that DNA immunization during antiretroviral therapy may be an effective strategy to treat HIV infection.

The Safety and Tolerability of Z-100 in Patients Infected with HIV-1

Z-100 is an extract of the Mycobacterium tuberculosis strain Aoyama B, which contains various polysaccharides. Aoyama B has previously been shown to induce a T helper 1-type cytokine response in various murine oncological models and has also demonstrated inhibitory activity against HIV-1 in vitro. This multicentre study primarily determined the safety of Z-100 in early HIV-1-infected patients who were treatment naive; were treatment experienced, but had elected to discontinue highly active antiretroviral therapy (HAART) 8 weeks or longer before the study; or were stable on their first or second HAART regimen for at least 12 weeks before the study. Thirty-two individuals participated in this study and self-injected either placebo, 20 μg or 40 μg Z-100 twice a week for 8 weeks. Z-100 was well tolerated and the safety profiles of the Z-100 treatment groups were not meaningfully different compared with the placebo group. Plasma levels of HIV-1 RNA were not statistically significantly different in any treatment group at the end of the treatment period. There were no statistically significant differences among the treatment groups in the change from baseline to week 8 for any of the biological endpoints including plasma levels of HIV-1 RNA; CD4+ and CD8+ T-cell counts; levels of macrophage inflammatory protein 1; soluble tumour necrosis factor receptor 1; C-reactive protein; interleukin-6; and granulocyte colony stimulating factor. Consequently, this trial demonstrates the safety of Z-100 in HIV-1 infected patients without evidence of any activity at the doses administered.

Effect of a protease inhibitor-induced genetic bottleneck on human immunodeficiency virus type 1 env gene populations

The initiation of drug therapy or the addition of a new drug to preexisting therapy can have a significant impact on human immunodeficiency virus type 1 (HIV-1) populations within a person. Drug therapy directed at reverse transcriptase and protease can result in dramatic decreases in virus load, causing a contraction in the virus population that represents a potential genetic bottleneck as a subset of virus with genomes carrying resistance mutations repopulate the host. While this bottleneck exerts an effect directly on the region that is being targeted by the drugs, it also affects other regions of the viral genome. We have applied heteroduplex tracking assays (HTA) specific to variable regions 1 and 2 (V1/V2) and variable region 3 (V3) of the HIV-1 env gene to analyze the effect of a genetic bottleneck created by the selection of resistance to ritonavir, a protease inhibitor. Subjects were classified into groups on the basis of the extent of the initial drop in virus load and the duration of virus load reduction. Subjects with a strong initial drop in virus load exhibited a loss of heterogeneity in the env region at virus load rebound; in contrast, subjects with a weak initial drop in virus load exhibited little to no loss of heterogeneity at virus load rebound in either region of env examined. The duration of virus load reduction also affected env populations. Subjects that had prolonged reductions exhibited slower population diversification and the appearance of new V1/V2 species after rebound. The longer reduction of virus load in these subjects may have allowed for improved immune system function, which in turn could have selected for new escape mutants. Subjects with rapid rebound quickly reequilibrated the entry env variants back into the resistant population. When the pro gene developed further resistance mutations subsequent to virus load rebound, no changes were observed in V1/V2 or V3 populations, suggesting that the high virus loads allowed the env populations to reequilibrate rapidly. The rapid equilibration of env variants during pro gene sequence transitions at high virus load suggests that recombination is active in defining the HIV-1 sequence population. Conversely, part of the success of suppressive antiviral therapy may be to limit the potential for evolution through recombination, which requires dually infected cells.

How effectively does HAART restore immune responses to Mycobacterium tuberculosis? Implications for tuberculosis control

Use of highly active antiretroviral treatment (HAART) has had a major impact on HIV-associated morbidity and mortality in industrialized countries. Access to HAART is now expanding in low-income countries where tuberculosis (TB) is the most important opportunistic disease. The incidence of TB has been fueled by the HIV epidemic and in many countries with high HIV prevalence current TB control measures are failing. HAART reduces the incidence of TB in treated cohorts by approximately 80% and therefore potentially has an important role in TB control in such countries. However, despite the huge beneficial effect of HAART, rates of TB among treated patients nevertheless remain persistently higher than among HIV-negative individuals. This observation raises the important question as to whether immune responses to Mycobacterium tuberculosis (MTB) are completely or only partially restored during HAART. Current data suggest that full restoration of circulating CD4 cell numbers occurs only among a minority of patients and that, even among these, phenotypic abnormalities and functional defects in lymphocyte subsets often persist. Suboptimal restoration of MTB-specific immune responses may greatly reduce the extent to which HAART is able to contribute to TB control at the community level because patients receiving HAART live much longer and yet would maintain a chronically heightened risk of TB.