Increased CCR5 and CXCR4 expression in Ethiopians living in Israel: environmental and constitutive factors

Higher CCR5 density on CD4 + T-cells in mothers and infants is associated with increased risk of in-utero HIV-1 transmission

OBJECTIVE

CCR5-tropic viruses are preferentially transmitted during perinatal HIV-1 infection. CCR5 density on CD4 + T-cells likely impacts susceptibility to HIV-1 infection.

DESIGN

Fifty-two mother-infant dyads were enrolled. All mothers were living with HIV-1, 27 of the infants acquired HIV-1 in utero and 25 infants remained uninfected.

METHODS

CCR5 density, together with frequencies of CD4 + and CD8 + T-cells expressing immune activation (CCR5, ICOS and HLA-DR) and immune checkpoint (TIGIT and PD-1) markers, were measured in whole blood from the dyads close to delivery.

RESULTS

Compared with mothers who did not transmit, mothers who transmitted HIV-1 had less exposure to ART during pregnancy ( P = 0.015) and higher plasma viral load close to delivery ( P = 0.0005). These mothers, additionally, had higher CCR5 density on CD4 + and CD8 + T-cells and higher frequencies of CCR5, ICOS and TIGIT-expressing CD8 + T-cells. Similarly, compared with infants without HIV-1, infants with HIV-1 had higher CCR5 density on CD4 + and CD8 + T-cells and higher frequencies of CCR5, TIGIT, and PD-1-expressing CD4 + and CD8 + T-cells as well as higher frequencies of HLA-DR-expressing CD8 + T-cells. CCR5 density on maternal CD4 + T-cells remained significantly associated with transmission after adjusting for maternal viral load and CD4 + T cell counts. Mother-infant dyads with shared high CCR5 density phenotypes had the highest risk of transmission/acquisition of infection compared with dyads with shared low-CCR5 density phenotypes.

CONCLUSION

This study provides strong evidence of a protective role for a combined mother-infant low CD4 + T-cell CCR5 density phenotype in in-utero transmission/acquisition of HIV-1.

HIV specific Th1 responses are altered in Ugandans with HIV and Schistosoma mansoni coinfection

BACKGROUND

Fishing communities surrounding Lake Victoria in Uganda have HIV prevalence of 28% and incidence rates of 5 per 100 person years. More than 50% of the local fishermen are infected with Schistosoma mansoni (S. mansoni). We investigated the role of S. mansoni coinfection as a possible modifier of immune responses against HIV. Using polychromatic flow cytometry and Gran-ToxiLux assays, HIV specific responses, T cell phenotypes, antibody-dependent cell-mediated cytotoxic (ADCC) potency and titres were compared between participants with HIV-S. mansoni coinfection and participants with HIV infection alone.

RESULTS

S. mansoni coinfection was associated with a modified pattern of anti-HIV responses, including lower frequency of bifunctional (IFNγ + IL-2 - TNF-α+) CD4 T cells, higher overall CD4 T cell activation and lower HIV ADCC antibody titres, compared to participants with HIV alone.

CONCLUSIONS

These results support the hypothesis that S. mansoni infection affects T cell and antibody responses to HIV in coinfected individuals.

Susceptibility to HIV-1 Acquisition linked to Malaria Exposure: A Case-control Study

HIV and malaria infection rates overlap across sub-Saharan Africa, but factors influencing their co-occurrence are unclear. In a case-control study, we investigated whether malaria exposure increases risk of HIV-1 acquisition. Prior to seroconverting, HIV-positive cases had significantly higher malaria-associated antibodies compared to HIV-negative controls, linking malaria exposure to HIV-1 acquisition.

Addressing an HIV cure in LMIC

HIV-1 persists in infected individuals despite years of antiretroviral therapy (ART), due to the formation of a stable and long-lived latent viral reservoir. Early ART can reduce the latent reservoir and is associated with post-treatment control in people living with HIV (PLWH). However, even in post-treatment controllers, ART cessation after a period of time inevitably results in rebound of plasma viraemia, thus lifelong treatment for viral suppression is indicated. Due to the difficulties of sustained life-long treatment in the millions of PLWH worldwide, a cure is undeniably necessary. This requires an in-depth understanding of reservoir formation and dynamics. Differences exist in treatment guidelines and accessibility to treatment as well as social stigma between low- and-middle income countries (LMICs) and high-income countries. In addition, demographic differences exist in PLWH from different geographical regions such as infecting viral subtype and host genetics, which can contribute to differences in the viral reservoir between different populations. Here, we review topics relevant to HIV-1 cure research in LMICs, with a focus on sub-Saharan Africa, the region of the world bearing the greatest burden of HIV-1. We present a summary of ART in LMICs, highlighting challenges that may be experienced in implementing a HIV-1 cure therapeutic. Furthermore, we discuss current research on the HIV-1 latent reservoir in different populations, highlighting research in LMIC and gaps in the research that may facilitate a global cure. Finally, we discuss current experimental cure strategies in the context of their potential application in LMICs.

Prevalence and Predisposing Factors of Intestinal Parasitic Infections Among HIV Positive Patients Visiting Nekemte Specialized Hospital, Western Ethiopia

Background

Intestinal parasites are endemic in many regions of the world where Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome (HIV/AIDS) patients are prevalent. This study aimed to assess the extent of intestinal parasitic infection (IPI) and predisposing factors among HIV positive patients visiting Nekemte Specialized Hospital, Western Ethiopia.

Methods

A hospital-based cross-sectional study was conducted among HIV positive patients and HIV negative controls who visited Nekemte Specialized Hospital from April to August 2020. A structured questionnaire was used to collect socio-demographic and risk-factor data. Stool samples and blood were collected and tested. Data were analyzed using SPSS version 20. P<0.05 was considered statistically significant.

Results

The occurrence of IPIs was considerably higher (73.3%) among HIV positive subjects compared to HIV negative controls (22.7%). Rate of infection with IPI was higher in individuals with CD4+ T cell count < 200 cells/μL. The species-specific distribution of parasites among HIV positive was higher for Giardia lamblia 35% followed by Entamoeba histolytica, 16% and hookworm 17.5%. Among the risk factors; age, educational status and occupation were significantly related with IPI (P<0.05). Habit of washing hands (OR=1.146, 95% CI: 0.189–1.936) and contact with animals (OR=2.926, 95% CI: 1.955–4.380) were expressively associated with IPI. Furthermore, eating raw meat, lack of safe water sources and usage were meaningfully connected with IPIs with OR=1.203, 95% CI: 0.590–2.454 and OR=0.172, 95% CI: 0.112–0.263, respectively.

Conclusion

HIV positive individuals were highly affected by IPI than HIV negative controls. The spreading of intestinal parasites was critically affected by reduced CD4+ T cell counts. Consistent screening and treatment of IPIs and awareness creation is very vital in improving the overall quality life of HIV/AIDS patients.

Infectious diseases among Ethiopian immigrants in Israel: a descriptive literature review

The mass immigration of Ethiopian Jews to Israel began in the 1980s. For most of these immigrants this was a time of sharp transition from a village life with very basic living conditions, in most cases without a regular supply of water, electricity, or healthcare services, to a modern Western urban society. The aim of this review was to search the medical literature on the characteristics of infectious diseases that are typical in Ethiopian immigrants (EI), using relevant keywords. There has been success in coping with diseases among EI, that are rare although recognized in Israel, in terms of screening and early identification. TB was common in Ethiopia over all the years of immigration to Israel. In contrast, HIV appeared in EI from 1999 when they had long stayovers in transition camps in Gondar and Addis Ababa where there was a high risk of infection with sexually transmitted diseases. There were often delays in diagnosing 'exotic' diseases that are endemic in Africa, but not well known in Israel, such as Onchocerciasis, Schistosomiasis, Strongyloidiasis, and Bartonella endocarditis, which cause severe morbidity and mortality among EI. We describe the effect on general morbidity in Israel, and how the healthcare services coped with these diseases, including obstacles, and failures and successes. In light of the ongoing immigration of African refugees to the United States and Europe, the Israeli experience can be of value to healthcare policy makers in developing strategies for the effective management by medical staff treating these immigrants.

Associations between schistosomiasis and HIV-1 acquisition risk in four prospective cohorts: a nested case-control analysis

INTRODUCTION

Globally, schistosomes infect approximately 200 million people, with 90% of infections in sub-Saharan Africa. Schistosomiasis is hypothesized to increase HIV-1 acquisition risk, and multiple cross-sectional studies reported strong associations. We evaluated this hypothesis within four large prospective cohorts.

METHODS

We conducted nested case-control analyses within three longitudinal cohorts of heterosexual HIV-1 serodiscordant couples and one female sex worker (FSW) cohort from Kenya and Uganda. The serodiscordant couples studies were conducted between 2004 and 2012 while the FSW cohort analysis included participant follow-up from 1993 to 2014. Cases HIV-1 seroconverted during prospective follow-up; three controls were selected per case. The presence of circulating anodic antigen in archived serum, collected prior to HIV-1 seroconversion, identified participants with active schistosomiasis; immunoblots determined the schistosome species. Data from serodiscordant couples cohorts were pooled, while the FSW cohort was analysed separately to permit appropriate confounder adjustment.

RESULTS

We included 245 HIV-1 seroconverters and 713 controls from the serodiscordant couples cohorts and 330 HIV-1 seroconverters and 962 controls from the FSW cohort. The prevalence of active schistosomiasis was 20% among serodiscordant couples and 22% among FSWs. We found no association between schistosomiasis and HIV-1 acquisition risk among males (adjusted odds ratio (aOR) = 0.99, 95% CI 0.59 to 1.67) or females (aOR = 1.21, 95% CI 0.64 to 2.30) in serodiscordant couples. Similarly, in the FSW cohort we detected no association (adjusted incidence rate ratio (aIRR) = 1.11, 95% CI 0.83 to 1.50). Exploring schistosome species-specific effects, there was no statistically significant association between HIV-1 acquisition risk and Schistosoma mansoni (serodiscordant couples: aOR = 0.90, 95% CI 0.56 to 1.44; FSW: aIRR = 0.83, 95% CI 0.53 to 1.20) or Schistosoma haematobium (serodiscordant couples: aOR = 1.06, 95% CI 0.46 to 2.40; FSW: aIRR = 1.64, 95% CI 0.93 to 2.87) infection.

CONCLUSIONS

Schistosomiasis was not a strong risk factor for HIV-1 acquisition in these four prospective studies. S. mansoni was responsible for the majority of schistosomiasis in these cohorts, and our results do not support the hypothesis that S. mansoni infection is associated with increased HIV-1 acquisition risk. S. haematobium infection was associated with a point estimate of elevated HIV-1 risk in the FSW cohort that was not statistically significant, and there was no trend towards a positive association in the serodiscordant couples cohorts.

Impact of Endemic Infections on HIV Susceptibility in Sub-Saharan Africa

Human immunodeficiency virus (HIV) remains a leading cause of global morbidity with the highest burden in Sub-Saharan Africa (SSA). For reasons that are incompletely understood, the likelihood of HIV transmission is several fold higher in SSA than in higher income countries, and most of these infections are acquired by young women. Residents of SSA are also exposed to a variety of endemic infections, such as malaria and various helminthiases that could influence mucosal and systemic immunology. Since these immune parameters are important determinants of HIV acquisition and progression, this review explores the possible effects of endemic infections on HIV susceptibility and summarizes current knowledge of the epidemiology and underlying immunological mechanisms by which endemic infections could impact HIV acquisition. A better understanding of the interaction between endemic infections and HIV may enhance HIV prevention programs in SSA.

Long-term effects of smallpox vaccination on expression of the HIV-1 co-receptor CCR5 in women

Background

Smallpox vaccinations were stopped globally in 1980. Recent studies have shown that in women, being smallpox vaccinated was associated with a reduced risk of HIV infection compared with not being smallpox vaccinated. At the initial infection, HIV-1 most often uses CCR5 as a co-receptor to infect the T-lymphocytes. We therefore investigated whether smallpox vaccination is associated with a down-regulation of CCR5 on the surface of peripheral T-lymphocytes in healthy women in Guinea-Bissau.

Methods

We included HIV seronegative women from Bissau, Guinea-Bissau, born before 1974, with and without a smallpox vaccination scar. Blood samples were stabilised in a TransFix buffer solution and stained for flow cytometry according to a T-cell maturation profile.

Results

Ninety-seven women were included in the study; 52 with a smallpox vaccination scar and 45 without a scar. No association between smallpox vaccination scar and CCR5 expression was found in any T-lymphocyte subtype.

Conclusion

Among HIV seronegative women, being smallpox vaccinated more than 40 years ago was not associated with a down-regulation of CCR5 receptors on the surface of peripheral T-lymphocytes.

Intestinal parasitic infections and its association with undernutrition and CD4 T cell levels among HIV/AIDS patients on HAART in Butajira, Ethiopia

BACKGROUND

Intestinal parasitic infections and HIV/AIDS have been the major public health problems and remain a vital cause of morbidity and mortality in developing countries. Both problems are linked in a vicious cycle. The magnitude of intestinal parasites was prevalent among people living with HIV/AIDS even in the HAART era. However, the pertinent risk factors associated with intestinal parasites among HIV/AIDS patients were not well investigated in Ethiopia particularly at Butajira town. Therefore, the aim of this study was to determine the prevalence of intestinal parasites and associated risk factors among HIV/AIDS patients on HAART in Butajira, Ethiopia.

METHOD

A cross-sectional study was conducted, and a total of 323 study subjects was involved in the study. A systematic random sampling technique was used to select each participant during data collection. Stool specimen was collected and processed using direct wet mount, formol-ether concentration technique, and modified Ziehl-Neelson staining techniques to identify both common and opportunistic intestinal parasites. Structured questionnaire was used to collect socio-demographic, environmental, clinical, and nutritional data. Both bivariate and multivariate logistic regression analyses were used to assess the association of various explanatory factors on intestinal parasites. P value ≤0.05 at 95% CI was considered statistically significant.

RESULTS

The overall prevalence of intestinal parasites was 35.9% (95% CI 31.0-40.9%). Protozoa's (Entanmoeba histolytica/dispar trophozoite, E. histolytica/dispar cyst, Giardia lamblia trophozoite, and G. lamblia cyst), helminths (Tanea species, Ascaris lumbricoides, Strongyloid stercoralis, Hookworm species and H. nana), and opportunistic intestinal parasites (Cryptosporidium parvum, Isospora belli) were observed in 57 (17.1%), 46 (14.4%), and 28 (8.7%) study participants respectively. Multivariate logistic regression analysis revealed that the presence of animals (AOR 6. 14; 95% CI 3.13, 12.0); using river water (AOR 4.87; 95% CI 1.14, 20.7); undernutrition (AOR 2.59; 95% CI 1.36-4.95); and level of immunosuppression (AOR 4.02; 95% CI 1.78-9.05 and AOR 2.84; 95% CI 1.37-5.89) were significantly associated with intestinal parasites.

CONCLUSIONS

The prevalence of intestinal parasites found to be higher among HIV/AIDS patients receiving HAART at Butajira Hospital, southern Ethiopia. Presence of animals, using river water, lower CD4 T cell count, and undernutrition were significant factors affecting intestinal parasites. Therefore, consistent detection of intestinal parasites and deworming of patients should be performed as well as improving health education on personal hygiene, avoiding contact with pit or domestic animals, and using safe or treated water. Furthermore, improving nutritional support and household food access are recommended.

Antihelminthics in helminth-endemic areas: effects on HIV disease progression

BACKGROUND

Helminth infections, such as soil-transmitted helminths, schistosomiasis, onchocerciasis, and lymphatic filariasis, are prevalent in many countries where human immunodeficiency virus (HIV) infection is also common. There is some evidence from observational studies that HIV and helminth co-infection may be associated with higher viral load and lower CD4+ cell counts. Treatment of helminth infections with antihelminthics (deworming drugs) may have benefits for people living with HIV beyond simply clearance of worm infections.This is an update of a Cochrane Review published in 2009 and we have expanded it to include outcomes of anaemia and adverse events.

OBJECTIVES

To evaluate the effects of deworming drugs (antihelminthic therapy) on markers of HIV disease progression, anaemia, and adverse events in children and adults.

SEARCH METHODS

In this review update, we searched online for published and unpublished studies in the Cochrane Library, MEDLINE, EMBASE, CENTRAL, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICRTP), ClinicalTrials.gov, and the WHO Global Health Library up to 29 September 2015. We also searched databases listing conference abstracts, scanned reference lists of articles, and contacted the authors of included studies.

SELECTION CRITERIA

We searched for randomized controlled trials (RCTs) that compared antihelminthic drugs with placebo or no intervention in HIV-positive people.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trials for eligibility and risk of bias. The primary outcomes were changes in HIV viral load and CD4+ cell count, and secondary outcomes were anaemia, iron deficiency, adverse events, and mortality events. We compared the effects of deworming using mean differences, risk ratios (RR), and 95% confidence intervals (CIs). We assessed the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Eight trials met the inclusion criteria of this review, enrolling a total of 1612 participants. Three trials evaluated the effect of providing antihelminthics to all adults with HIV without knowledge of their helminth infection status, and five trials evaluated the effects of providing deworming drugs to HIV-positive individuals with confirmed helminth infections. Seven trials were conducted in sub-Saharan Africa and one in Thailand. Antihelminthics for people with unknown helminth infection statusProviding antihelminthics (albendazole and praziquantel together or separately) to HIV-positive adults with unknown helminth infection status may have a small suppressive effect on mean viral load at six weeks but the 95% CI includes the possibility of no effect (difference in mean change -0.14 log10 viral RNA/mL, 95% CI -0.35 to 0.07, P = 0.19; one trial, 166 participants, low quality evidence).Repeated dosing with deworming drugs over two years (albendazole every three months plus annual praziquantel), probably has little or no effect on mean viral load (difference in mean change 0.01 log10 viral RNA, 95% CI: -0.03 to -0.05; one trial, 917 participants, moderate quality evidence), and little or no effect on mean CD4+ count (difference in mean change 2.60 CD4+ cells/µL, 95% CI -10.15 to 15.35; P = 0.7; one trial, 917 participants, low quality evidence). Antihelminthics for people with confirmed helminth infectionsTreating confirmed helminth infections in HIV-positive adults may have a small suppressive effect on mean viral load at six to 12 weeks following deworming (difference in mean change -0.13 log10 viral RNA, 95% CI -0.26 to -0.00; P = 0.04; four trials, 445 participants, low quality evidence). However, this finding is strongly influenced by a single study of praziquantel treatment for schistosomiasis. There may also be a small favourable effect on mean CD4+ cell count at 12 weeks after deworming in HIV-positive populations with confirmed helminth infections (difference in mean change 37.86 CD4+ cells/µL, 95% CI 7.36 to 68.35; P = 0.01; three trials, 358 participants, low quality evidence). Adverse events and mortality There is no indication that antihelminthic drugs impart additional risks in HIV-positive populations. However, adverse events were not well reported (very low quality evidence) and trials were underpowered to evaluate effects on mortality (low quality evidence).

AUTHORS' CONCLUSIONS

There is low quality evidence that treating confirmed helminth infections in HIV-positive adults may have small, short-term favourable effects on markers of HIV disease progression. Further studies are required to confirm this finding. Current evidence suggests that deworming with antihelminthics is not harmful, and this is reassuring for the routine treatment of confirmed or suspected helminth infections in people living with HIV in co-endemic areas.Further long-term studies are required to make confident conclusions regarding the impact of presumptively deworming all HIV-positive individuals irrespective of helminth infection status, as the only long-term trial to date did not demonstrate an effect.

TLR2-Modulating Lipoproteins of the Mycobacterium tuberculosis Complex Enhance the HIV Infectivity of CD4+ T Cells

Co-infection with Mycobacterium tuberculosis accelerates progression from HIV to AIDS. Our previous studies showed that M. tuberculosis complex, unlike M. smegmatis, enhances TLR2-dependent susceptibility of CD4+ T cells to HIV. The M. tuberculosis complex produces multiple TLR2-stimulating lipoproteins, which are absent in M. smegmatis. M. tuberculosis production of mature lipoproteins and TLR2 stimulation is dependent on cleavage by lipoprotein signal peptidase A (LspA). In order to determine the role of potential TLR2-stimulating lipoproteins on mycobacterial-mediated HIV infectivity of CD4+ T cells, we generated M. smegmatis recombinant strains overexpressing genes encoding various M. bovis BCG lipoproteins, as well as a Mycobacterium bovis BCG strain deficient in LspA (ΔlspA). Exposure of human peripheral blood mononuclear cells (PBMC) to M. smegmatis strains overexpressing the BCG lipoproteins, LprF (p<0.01), LprH (p<0.05), LprI (p<0.05), LprP (p<0.001), LprQ (p<0.005), MPT83 (p<0.005), or PhoS1 (p<0.05), resulted in increased HIV infectivity of CD4+ T cells isolated from these PBMC. Conversely, infection of PBMC with ΔlspA reduced HIV infectivity of CD4+ T cells by 40% relative to BCG-infected cells (p<0.05). These results may have important implications for TB vaccination programs in areas with high mother-to-child HIV transmission.

Levels of Genital Tract Defensins and Cytokines Differ between HIV-Uninfected US and African Women

PROBLEM

To explore the impact of race and geographic region on biomarkers of HIV risk and vaginal health, differences in soluble immune mediators were measured in US versus African and US white versus US black women at enrollment into a phase 2 microbicide trial.

METHODS

Levels of soluble mucosal immune mediators and inhibitory activity against E. coli, which may serve as biomarkers of risk for HIV and other genital tract infections, were quantified in cervicovaginal lavage (CVL) collected from HIV-uninfected women in the United States (n = 73) and Africa (n = 73). Differences between groups were analyzed with multivariable logistic regression models for dichotomous variables and linear regression models for continuous variables.

RESULTS

Secretory leukocyte protease inhibitor, lactoferrin, human beta defensins, interleukin (IL)-8, and interferon-gamma-induced protein-10 were significantly higher in US compared to African women in multivariable analysis, but only IL-1β was significantly different between US white and black women. E. coli inhibitory activity did not differ among groups in adjusted analyses.

CONCLUSION

Differences in soluble mucosal immunity between US and African women may play an important role in women's risk for HIV and other genital tract infections and response to prevention strategies including vaginal microbicides and should be considered in future studies.

Sex, age, race and intervention type in clinical studies of HIV cure: a systematic review

This systematic review was undertaken to determine the extent to which adult subjects representing sex (female), race (nonwhite), and age (>50 years) categories are included in clinical studies of HIV curative interventions and thus, by extension, the potential for data to be analyzed that may shed light on the influence of such demographic variables on safety and/or efficacy. English-language publications retrieved from PubMed and from references of retrieved papers describing clinical studies of curative interventions were read and demographic, recruitment year, and intervention-type details were noted. Variables of interest included participation by sex, age, and race; changes in participation rates by recruitment year; and differences in participation by intervention type. Of 151 publications, 23% reported full demographic data of study enrollees, and only 6% reported conducting efficacy analyses by demographic variables. Included studies recruited participants from 1991 to 2011. No study conducted safety analyses by demographic variables. The representation of women, older people, and nonwhites did not reflect national or international burdens of HIV infection. Participation of demographic subgroups differed by intervention type and study location. Rates of participation of demographic groups of interest did not vary with time. Limited data suggest efficacy, particularly of early therapy initiation followed by treatment interruption, may vary by demographic variables, in this case sex. More data are needed to determine associations between demographic characteristics and safety/efficacy of curative interventions. Studies should be powered to conduct such analyses and cure-relevant measures should be standardized.

Empiric deworming and CD4 count recovery in HIV-infected Ugandans initiating antiretroviral therapy

BACKGROUND

There is conflicting evidence on the immunologic benefit of treating helminth co-infections ("deworming") in HIV-infected individuals. Several studies have documented reduced viral load and increased CD4 count in antiretroviral therapy (ART) naïve individuals after deworming. However, there are a lack of data on the effect of deworming therapy on CD4 count recovery among HIV-infected persons taking ART.

METHODOLOGY/PRINCIPAL FINDINGS

To estimate the association between empiric deworming therapy and CD4 count after ART initiation, we performed a retrospective observational study among HIV-infected adults on ART at a publicly operated HIV clinic in southwestern Uganda. Subjects were assigned as having received deworming if prescribed an anti-helminthic agent between 7 and 90 days before a CD4 test. To estimate the association between deworming and CD4 count, we fit multivariable regression models and analyzed predictors of CD4 count, using a time-by-interaction term with receipt or non-receipt of deworming. From 1998 to 2009, 5,379 subjects on ART attended 21,933 clinic visits at which a CD4 count was measured. Subjects received deworming prior to 668 (3%) visits. Overall, deworming was not associated with a significant difference in CD4 count in either the first year on ART (β = 42.8; 95% CI, -2.1 to 87.7) or after the first year of ART (β =  -9.9; 95% CI, -24.1 to 4.4). However, in a sub-analysis by gender, during the first year of ART deworming was associated with a significantly greater rise in CD4 count (β = 63.0; 95% CI, 6.0 to 120.1) in females.

CONCLUSIONS/SIGNIFICANCE

Empiric deworming of HIV-infected individuals on ART conferred no significant generalized benefit on subsequent CD4 count recovery. A significant association was observed exclusively in females and during the initial year on ART. Our findings are consistent with recent studies that failed to demonstrate an immunologic advantage to empirically deworming ART-naïve individuals, but suggest that certain sub-populations may benefit.

Helminth-associated systemic immune activation and HIV co-receptor expression: response to albendazole/praziquantel treatment

Background

It has been hypothesized that helminth infections increase HIV susceptibility by enhancing systemic immune activation and hence contribute to elevated HIV-1 transmission in sub-Saharan Africa.

Objective

To study systemic immune activation and HIV-1 co-receptor expression in relation to different helminth infections and in response to helminth treatment.

Methods

HIV-negative adults with (n = 189) or without (n = 57) different helminth infections, as diagnosed by Kato-Katz, were enrolled in Mbeya, Tanzania. Blinded to helminth infection status, T cell differentiation (CD45RO, CD27), activation (HLA-DR, CD38) and CCR5 expression was determined at baseline and 3 months after Albendazole/Praziquantel treatment. Plasma cytokine levels were compared using a cytometric bead array.

Results

Trichuris and Ascaris infections were linked to increased frequencies of “activated” CD4 and/or CD8 T cells (p<0.05), whereas Hookworm infection was associated with a trend towards decreased HLA-DR⁺ CD8 T cell frequencies (p = 0.222). In Trichuris infected subjects, there was a linear correlation between HLA-DR⁺ CD4 T cell frequencies and the cytokines IL-1β and IL-10 (p<0.05). Helminth treatment with Albendazole and Praziquantel significantly decreased eosinophilia for S. mansoni and Hookworm infections (p<0.005) but not for Trichuris infection and only moderately modulated T cell activation. CCR5 surface density on memory CD4 T cells was increased by 1.2-fold during Trichuris infection (p-value: 0.053) and reduced after treatment (p = 0.003).

Conclusions

Increased expression of T cell activation markers was associated with Trichuris and Ascaris infections with relatively little effect of helminth treatment.

Helminth infections are common in sub-Saharan Africa where about half of the population may be infected with one or more helminth species. HIV infection is also highly prevalent in this region. Because of the geographic overlap of helminth and HIV infections, it has been hypothesized that helminth infections may increase susceptibility to HIV by increasing systemic immune activation, which has been linked to increased HIV susceptibility. We therefore investigated the profile of T cell activation in individuals infected with different helminth species before and after helminth treatment within the WHIS cohort in Mbeya, Tanzania. Our study shows that systemic T cell activation differs between infections with different helminths. Particularly Trichuris but also Ascaris and S. mansoni infections were linked to increased frequencies of activated, HLA-DR⁺ T cells with relatively little effect of helminth treatment. Hookworm infection was associated with a trend towards decreased frequencies of activated, HLA-DR⁺ CD8⁺ T cells. Our study supports the concept that helminth infections, which are linked to systemic immune activation, could potentially also contribute to increased HIV transmission.

High CCR5 density on central memory CD4+ T cells in acute HIV-1 infection is mostly associated with rapid disease progression

CD4+ central memory T cells play a critical role in the pathogenesis of simian immunodeficiency virus disease, and the CCR5 density on the surface of CD4 T cells is an important factor in human immunodeficiency virus (HIV)-1 disease progression. We hypothesized that quantifying central memory cells and CCR5 expression in the early stages of HIV-infection could provide useful prognostic information. We enrolled two different groups of acute HIV-infected subjects. One group progressed to CD4 T cell numbers below 250 cells/µl within 2 years (CD4 Low group), while the other group maintained CD4 cell counts above 450 cells/µl over 2 years (CD4 High group). We compared the CCR5 levels and percentage of CD4 subsets between the two groups during the 1st year of HIV infection. We found no differences between the two groups regarding the percentage of naïve, central memory and effector memory subsets of CD4 cells during the 1st year of HIV-1 infection. CCR5 levels on CD4+ CM subset was higher in the CD4 Low group compared with the CD4 High group during the 1st year of HIV-1 infection. High CCR5 levels on CD4 central memory cells in acute HIV infection are mostly associated with rapid disease progression. Our data suggest that low CCR5 expression on CD4 central memory cells protects CD4 cells from direct virus infection and favors the preservation of CD4⁺ T cell homeostasis.

Marked differences in CCR5 expression and activation levels in two South African populations

The chemokine receptor CCR5 is pivotal in determining an individual's susceptibility to HIV-1 infection and rate of disease progression. To establish whether population-based differences exist in cell surface expression of CCR5 we evaluated the extent of CCR5 expression across all peripheral blood cell types in individuals from two populations, South African Africans (SAA) and South African Caucasians (SAC). Significant differences in CCR5 expression, both in number of CCR5 molecules per cell (density) and the percentage of CCR5-expressing cells, were observed between the two study groups, within all cell subsets. Most notably, the percentage of all CCR5(+) cell subsets was significantly lower in SAC compared with SAA individuals (P < 0·01) among natural killer (NK) -cell subsets (CD56(+) , CD16(+) CD56(+) and CD56(dim) ) whereas CCR5 density was significantly higher in SAC compared with SAA individuals in CCR5(+) CD8(+) T-cell subsets and CCR5(+) NK-cell subsets (CD56(+) , CD16(+) CD56(+) and CD56(dim) ) (all P < 0·05). These relationships were maintained after exclusion of CCR5Δ32 heterozygous individuals (n = 7) from the SAC dataset. The SAA individuals exhibited significantly higher cell activation levels, as measured by HLA-DR expression, than SAC individuals in CD4(+) T-cell subsets (P = 0·002) and CD56(+) NK-cell subsets (P < 0·001). This study serves to demonstrate that ethnically divergent populations show marked differences in both cell activation and CCR5 expression, which are likely to impact on both susceptibility to HIV-1 infection and the rate of HIV-1 disease progression.

Mycobacterium tuberculosis complex enhances susceptibility of CD4 T cells to HIV through a TLR2-mediated pathway

Among HIV-infected individuals, co-infection with Mycobacterium tuberculosis is associated with faster progression to AIDS. We investigated the hypothesis that M. bovis BCG and M. tuberculosis (Mtb complex) could enhance susceptibility of CD4+ cells to HIV infection. Peripheral blood mononuclear cells (PBMCs) collected from healthy donors were stimulated with M. bovis BCG, M. tuberculosis CDC1551 and M. smegmatis MC²155, and stimulated CD4+ cells were infected with R5-and X4-tropic single replication-competent pseudovirus. CD4+ cells stimulated with Mtb complex showed enhanced infection with R5- and X4-tropic HIV, compared to unstimulated cells or cells stimulated with M. smegmatis (p<0.01). Treatment with TLR2 siRNA reversed the increased susceptibility of CD4+ cells with R5- and X4-tropic virus induced by Mtb complex. These findings suggest that TB infection and/or BCG vaccination may be a risk factor for HIV acquisition.

Impact of CD8+ T-cell activation on CD4+ T-cell recovery and mortality in HIV-infected Ugandans initiating antiretroviral therapy

OBJECTIVES

To assess whether T-cell activation independently predicts the extent of CD4(+) T-cell recovery and mortality in HIV-infected Ugandans initiating antiretroviral therapy (ART).

DESIGN

Prospective cohort study.

METHODS

HIV-infected adults starting ART and achieving a plasma HIV RNA level (VL) less than 400 copies/ml by month 6 were sampled from the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort in Mbarara, Uganda. CD4 count, VL, and the percentage-activated (CD38(+)HLA-DR(+)) T cells were measured every 3 months.

RESULTS

Of 451 HIV-infected Ugandans starting ART, most were women (70%) with median pre-ART values: age, 34 years; CD4 count, 135 cells/μl; and VL, 5.1 log(10) copies/ml. Of these, 93% achieved a VL less than 400 copies/ml by month 6 and were followed for a median of 24 months, with 8% lost to follow-up at 3 years. Higher pre-ART CD8(+) T-cell activation was associated with diminished CD4 recovery after year 1, after adjustment for pre-ART CD4 count, VL, and sex (P = 0.017). Thirty-four participants died, 15 after month 6. Each 10% point increase in activated CD8(+) T cells at month 6 of suppressive ART was associated with a 1.6-fold increased hazard of subsequent death after adjusting for pretherapy CD4 count (P = 0.048).

CONCLUSIONS

Higher pre-ART CD8(+) T-cell activation independently predicts slower CD4(+) T-cell recovery and higher persistent CD8(+) T-cell activation during ART-mediated viral suppression independently predicts increased mortality among HIV-infected Ugandans. Novel therapeutic strategies aimed at preventing or reversing immune activation during ART are needed in this setting.

Correlation among HLA alleles A*02/A*24, HLA-DR expression and resistance to HIV-1 infection in Chinese populations

Aims: The reason why populations that are highly exposed to HIV-1 but that remain seronegative (ESNs) possess the capacity of HIV-1 resistance is uncertain. In this study, we tried to find the relationship among certain T-cell receptors, HLA genotype and susceptibility to HIV-1 in Chinese individuals. Materials & methods: T-cell subsets, activation markers of T cells and co-receptors of HIV-1 infection were analyzed in ESNs, healthy controls and HIV-1 carriers. HLA genotypes of the three populations were also assayed. Results: We found that the ESNs had significantly lower percentages of HLA-DR+ CD4 T cells and HLA-DR+ CD8 T cells than healthy controls and HIV-1 carriers. Healthy controls could be clearly divided into a low-expression group and a high-expression group according to HLA-DR+ CD8 T-cell expression. Almost all of the ESNs belonged to the HLA-DR+CD8 low-expression group (33/37), whereas only just over half of the healthy controls were in the low-expression group (59/101; p < 0.001). In healthy controls, the distribution of the A*02 allele showed significant negative correlation with HLA-DR+CD8 expression (p = 0.008), whereas the distribution of the A*24 displayed a significant positive correlation with HLA-DR+CD8 expression (p = 0.045). Conclusion: HLA-DR+ CD8 T-cell expression was an important indicator of susceptibility to HIV-1 infection in Chinese individuals. A*02 and A*24 allelic distribution had a close correlation with HLA-DR expression.

Mendelian randomization: potential use of genetics to enable causal inferences regarding HIV-associated biomarkers and outcomes

PURPOSE OF REVIEW

It is unknown whether biomarkers simply correlate with or are causal for HIV-associated outcomes. Mendelian randomization is a genetic epidemiologic approach used to disentangle causation from association. Here, we discuss the potential use of Mendelian randomization for differentiating whether biomarkers are correlating with or causal for HIV-associated outcomes.

RECENT FINDINGS

Mendelian randomization refers to the random allocation of alleles at the time of gamete formation. In observational epidemiology, this refers to the use of genetic variants to estimate a causal effect between a modifiable risk factor and an outcome of interest. A formal Mendelian randomization study using a genetic marker as a proxy for the biomarker has not been conducted in the HIV field. However, in the postgenomic era, this approach is being used increasingly. Examples are evidence for the causal role of BMI in blood pressure and noncausal role of C-reactive protein in coronary heart disease. We discuss the conceptual framework, uses, and limitations of Mendelian randomization in the context of HIV infection as well as specific biomarkers (IL-6, C-reactive protein) and genetic determinants (e.g., in CCR5, chemokine, and DARC genes) that associate with HIV-related outcomes.

SUMMARY

Making the distinction between correlation and causality has particular relevance when a biomarker (e.g., IL-6) is potentially modifiable, in which case a biomarker-guided targeted treatment strategy may be feasible. Although the tenets of Mendelian randomization rest on strong assumptions, and conducting a Mendelian randomization study in HIV infection presents many challenges, it may offer the potential to identify causal biomarkers for HIV-associated outcomes.

Biological factors that may contribute to regional and racial disparities in HIV prevalence

Despite tremendous regional and subregional disparities in HIV prevalence around the world, epidemiology consistently demonstrates that black communities have been disproportionately affected by the pandemic. There are many reasons for this, and a narrow focus on socio-behavioural causes may be seen as laying blame on affected communities or individuals. HIV sexual transmission is very inefficient, and a number of biological factors are critical in determining whether an unprotected sexual exposure to HIV results in productive infection. This review will focus on ways in which biology, rather than behaviour, may contribute to regional and racial differences in HIV epidemic spread. Specific areas of focus are viral factors, host genetics, and the impact of co-infections and host immunology. Considering biological causes for these racial disparities may help to destigmatize the issue and lead to new and more effective strategies for prevention.

Effect of treating co-infections on HIV-1 viral load: a systematic review

Co-infections contribute to HIV-related pathogenesis and often increase viral load in HIV-infected people. We did a systematic review to assess the effect of treating key co-infections on plasma HIV-1-RNA concentrations in low-income countries. We identified 18 eligible studies for review: two on tuberculosis, two on malaria, six on helminths, and eight on sexually transmitted infections, excluding untreatable or non-pathogenic infections. Standardised mean plasma viral load decreased after the treatment of co-infecting pathogens in all 18 studies. The standardised mean HIV viral-load difference ranged from -0.04 log(10) copies per mL (95% CI -0.24 to 0.16) after syphilis treatment to -3.47 log(10) copies per mL (95% CI -3.78 to -3.16) after tuberculosis treatment. Of 14 studies with variance data available, 12 reported significant HIV viral-load differences before and after treatment. Although many of the viral-load reductions were 1.0 log(10) copies per mL or less, even small changes in plasma HIV-RNA concentrations have been shown to slow HIV progression and could translate into population-level benefits in lowering HIV transmission risk.

Intestinal parasites infection among immunocompromised patients in Riyadh, Saudi Arabia

This study was conducted to determine the prevalence of intestinal parasites among immunocompromised patients in Riyadh, Saudi Arabia. Fecal samples were collected from 136 immunocompromised patients (52 females and 84 males), aged 2 to 69 years. Specimens were fixed with 10% formalin for 30 min (2-3 g fecal(-1)) and then concentrated by a formalin-ether sedimentation technique. Samples were examined as wet saline mounts and in iodine preparation for detection of protozoan oocysts, cysts, helminthic eggs and larvae. Permanent stained smears were performed for intestinal coccidian parasites by the modified Ziehl-Neelsen technique and the modified trichrome stain. Intestinal parasites were detected in 54 (39.7%) most of them (25.7%) were with diarrhea. More specifically the following parasites were detected Cryptosporidium parvum 11(8.1%), Giardia lamblia 9 (6.6%), Cyclospora cayetanensis 8 (5.9%), Blastocystis hominis 7 (5.2%), Entamoeba histolytica 7 (5.2%), Entamoeba coli 5 (3.7%), Strongyloides stercoralis 3 (2.2%), Ascaris lumbricoides 1 (0.7%), Hymenolepis nana 1 (0.7%), Dicrocoelium dendriticum 1 (0.7%) and Hook worm 1 (0.7%). The most common parasite associated with diarrhea in patients, was C. parvum (p < 0.001), followed by G. lamblia, C. cayetanensis and E. histolytica. However, differences between different age groups were statistically non-significant. Similarly, no significant difference in the infection rate were found between male and female patients.

Viral tropism, fitness and pathogenicity of HIV-1 subtype C

The majority of studies on HIV-1 pathogenesis have been conducted on subtype B HIV-1 (B-HIV) strains. However, B-HIV strains constitute the minority of HIV-1 cases worldwide, and are not common in regions that stand to benefit the most from advances in HIV-1 research such as southern Africa and Asia, where the HIV-1 pandemic is at its worst. The majority of individuals with HIV-1 are infected with subtype C HIV-1 (C-HIV) and reside in Southern Africa and Central Asia. Relatively little is known about C-HIV, but current evidence suggests the pathogenesis of C-HIV is distinct from B-HIV and other HIV-1 subtypes. This article summarizes what is currently known about the viral tropism, fitness and pathogenicity of C-HIV, and compares and contrasts these features to B-HIV. A thorough understanding of the molecular pathogenesis of C-HIV is important for a targeted approach to developing vaccines and novel drugs optimized for effectiveness in populations that are most in need.

Intestinal parasitic infections in relation to HIV/AIDS status, diarrhea and CD4 T-cell count

BACKGROUND

HIV infection has been modifying both the epidemiology and outcome of parasitic infections. Hence, this study was undertaken to determine the prevalence of intestinal parasitic infection among people with and without HIV infection and its association with diarrhea and CD4 T-cell count.

METHODS

A cross-sectional study was conducted at Hawassa Teaching and Referral Hospital focusing on HIV positive individuals, who gave blood for CD4 T-cell count at their first enrollment and clients tested HIV negative from November, 2008 to March, 2009. Data on socio-demographic factors and diarrhea status were obtained by interviewing 378 consecutive participants (214 HIV positive and 164 HIV negative). Stool samples were collected from all study subjects and examined for parasites using direct, formol-ether and modified acid fast stain techniques.

RESULTS

The prevalence of any intestinal parasitic infection was significantly higher among HIV positive participants. Specifically, rate of infection with Cryptosporidium, I. belli, and S. stercoralis were higher, particularly in those with CD4 count less than 200 cells/microL. Diarrhea was more frequent also at the same lower CD4 T-cell counts.

CONCLUSION

Immunodeficiency increased the risk of having opportunistic parasites and diarrhea. Therefore; raising patient immune status and screening at least for those treatable parasites is important.

Does cyclosporin A affect CCR5 and CXCR4 expression in primary HIV-1-infected patients?

BACKGROUND

CCR5 and CXCR4 are the major coreceptors of HIV required for successful viral entry. No information exists on the effect of cyclosporin A (CsA) on expression of CCR5 and CXCR4. A longitudinal study of the coreceptors' expression in freshly isolated peripheral blood mononuclear cells (PBMC) of patients with primary HIV infection (PHI) was performed.

METHODS

Patients received highly active antiretroviral therapy (HAART) alone (n = 7) or with CsA (HAART + CsA) (n = 8). Flow cytometric data were analyzed at T0 (baseline), two (T2), six (T6), and twelve (T12) months after therapy initiation.

RESULTS

At T0 PHI subjects presented a statistically significant higher count and percentage of CD8+CCR5+ lymphocytes compared to healthy donors (HD) (mean +/- SD, 2,240 +/- 1,998 vs 181 +/- 89 cells/microl). Conversely, CD4+CXCR4+ lymphocytes were less abundant in PHI than in HD (443 +/- 337 vs 673 +/- 339 cells/microl), whereas CD4+CCR5+ lymphocytes were substantially comparable (169 +/- 167 vs 126 +/- 60 cells/microl). In the follow up no differences between HAART and HAART + CsA groups reached statistical significance in CD4 lymphocytes. CD4+CCR5- lymphocytes displayed a rapid recovery after therapy initiation, similarly to the CD4+CXCR4+ subset. In CD8 lymphocytes a statistically significant difference between HAART and HAART + CsA patients occurred at T2 when HAART + CsA patients presented a lower absolute count of the CD8+CXCR4+ subset compared to the HAART group. The major change after therapy initiation in all PHI patients was a striking drop of CD8+CCR5+ lymphocytes; moreover, the CD8+CXCR4- subset behaved similarly. The decrement of CD8+CCR5+ lymphocytes paralleled the decline of viremia and CD8+CD38+ lymphocytes, with the sharpest slope at T2. Conversely, RANTES levels increased at T2 and remained elevated during the follow up.

CONCLUSIONS

CsA cotreatment in PHI patients appears not to substantially modify HIV coreceptors' expression in PBMC. However, this novel piece of information should be used with caution, since this was not a randomized study between the HAART and the HAART + CsA groups.

HIV and helminth co-infection: is deworming necessary?

We have previously suggested that helminth infections play a major role in the pathogenesis of HIV-1 infection in Africa and other developing areas, due to their profound effects on the host immune system, which make those infected more susceptible to HIV-1 infection and less able to cope with it. Chronic immune activation with a dominant Th2 profile, and anergy, are the hallmarks of chronic helminth infection, and may therefore account for most of these effects. In the present review, we summarize the studies that have addressed these issues and argue that despite some conflicting results, the cumulative immunological and epidemiological evidence is in favour of deworming as a preventive and possible therapeutic measure vis-à-vis HIV-1 infection. We suggest that it should be at least tested on a wider and larger scale than has been done until now, because of its immense potential impact on the still raging AIDS epidemic in developing countries.

Helminths and HIV infection: epidemiological observations on immunological hypotheses

Parasitic helminths have co-evolved with the mammalian immune system. Current hypotheses suggest that immunological stimulation in the presence of helminths is balanced by immuno-regulation and by the broad spectrum of mechanisms possessed by helminths for countering the host immune response. The degree to which this balance is perfected, and the mechanisms by which this is achieved, vary between helminth species; we suggest that this is reflected not only in the degree of pathology induced by helminths but also in a variety of relationships with HIV infection and HIV disease. Available epidemiological data regarding interactions between helminths and HIV are largely observational; results are variable and generally inconclusive. Well designed, controlled intervention studies are required to provide definitive information on the species-specific nature of these interactions and on the advantages, disadvantages and optimal timing of de-worming in relation to HIV infection.

Increased TGF-beta, Cbl-b and CTLA-4 levels and immunosuppression in association with chronic immune activation

In this study we investigated the mechanisms mediating T-cell hyporesponsiveness in chronically immune-activated individuals. We analyzed in healthy and persistently helminth-infected individuals the relationship between immune activation and general T-cell hyporesponsiveness, Th3/regulatory T-cell expression, transforming growth factor-beta (TGF-beta) secretion, CTL-associated antigen 4 (CTLA-4) levels, Casitas B-cell lymphoma-b (Cbl-b) (a negative regulator of T-cell activation) levels and phosphorylation of mitogen-activated protein kinases/extracellular signal-regulated kinase (ERK)-1 and -2. We found a very significant increase in plasma levels of TGF-beta and intracellular pools of CTLA-4 and Cbl-b in association with immune activation, which correlates with decreased T-cell responses to anti-CD3 stimulation. We demonstrate that the impaired activity of ERK of peripheral T cells in highly immune-activated individuals is associated with increased levels of CTLA-4 and Cbl-b. Interestingly, in some, but not in all, of these immune-activated individuals, induction of Cbl-b intracellular pools occurs by TGF-beta or CTLA-4 stimulation. We suggest that the higher levels of CTLA-4 and TGF-beta, both involved in the induction of Cbl-b, point at potential mechanisms underlying general and antigen-specific immune hyporesponsiveness in chronically infected individuals.

TLR9 expression is related to immune activation but is impaired in individuals with chronic immune activation

Millions of individuals in developing countries are infected with helminths and other chronic infectious diseases, such as HIV-1, which lead to persistent immune activation and unbalanced immune state. We have suggested that the capacity of chronically immune activated individuals to protect themselves, cope with infections, and mount protective immunity following vaccination, is highly impaired. Here we examined the expression of toll-like receptor 9 (TLR9), as an essential component in the recognition of immunostimulating bacterial CpG-DNA motifs, in different subsets of human peripheral blood mononuclear cells (PBMC) obtained from chronically immune activated and non-activated individuals. TLR9 expression was correlated to immune cell activation and was upregulated following phytohemagglutinin or anti-CD3 activation. PBMC obtained from chronically immune activated individuals had a different overall pattern of TLR9 expression, including reduced upregulation of this receptor following additional immune activation, and diminished responsiveness to CpG-DNA stimulation, in comparison to non-activated individuals. These differences may partly account for the reduced capacity of chronically immune activated individuals to mount effective immune responses and strengthen the notion that the host immune background should be considered in the design and trial of potential adjuvants and vaccines.

Treatment of intestinal helminths does not reduce plasma concentrations of HIV-1 RNA in coinfected Zambian adults

BACKGROUND

Infection with intestinal helminths may stimulate dysfunctional immune responses in human immunodeficiency virus (HIV)-infected persons. Studies have yielded conflicting results regarding the impact of antihelminthic treatment on plasma concentrations of HIV-1 RNA.Methods. We conducted a prospective study of 54 HIV-1- and helminth-coinfected and 57 HIV-1-infected, helminth-uninfected asymptomatic adults living in Lusaka, Zambia, to assess the impact of antihelminthic treatment on plasma concentrations of HIV-1 RNA.

RESULTS

Median baseline viral load was 0.33 log(10) copies/mL lower in the helminth-infected group than in the uninfected group. Mean viral load between pretreatment and posttreatment visits increased in the helminth-infected (mean, 4.23 vs. 4.29 log(10) copies/mL; P=.6) and helminth-uninfected (mean, 4.39 vs. 4.52 log(10) copies/mL; P=.2) groups. Helminth-infected participants with high pretreatment viral loads had a mean 0.25-log(10) copies/mL decrease after treatment (P=.3), and helminth-uninfected participants had a mean 0.02-log(10) copies/mL decrease (P=.8).

CONCLUSIONS

We did not find an overall association between treatment of intestinal helminth infections and reduction in viral load in coinfected adults. Future studies may need to focus on adults with intense helminth infections who live in rural areas or on adults or children who harbor higher helminth burdens and plasma concentrations of HIV-1 RNA.

Soluble chemokine CCR5 receptor is present in human plasma

In view of the natural resistance to infection by HIV and occasional delayed clinical manifestation of the disease, as also the fact that the virus is able to enter only cells that express CD4 and a co-receptor, we initiated a search for a soluble co-receptor that might compete with its membrane counterpart. Using a sandwich ELISA system, a soluble human CCR5 receptor (sCCR5) was indeed detected in the circulation. Immunoprecipitation of sCCR5-positive plasma samples from Israelis of Ethiopian and non-Ethiopian origin with mAb 2D7, a conformation-dependent anti-CCR5 antibody, revealed the presence of an approximately 22 kDa protein. A panel of antibodies directed against the membrane receptor was used to characterize the structure of the soluble CCR5: mAb CTC8, recognizing the N-terminal sequence of the protein, 10YDIN13; "multidomain" mAbs FAB181B and FAB183B that are dependent upon the presence of Q93 and D95 in ECL1 and K171 and E172 in ECL2A, and mAb FAB182B, recognizing the stretch 184YSQYQF189, which spans the C-terminal part of the second extracellular loop. The presence of short soluble CCR5 in human plasma has not been previously described. Among HIV-negative non-Ethiopian Israelis, 20.4% were sCCR5-positive, as against only 10.5% in HIV-positives. However, 7.1% of HIV-negative Ethiopian Israelis were sCCR5 positive, as were 5.6% HIV-positives. Plasma concentrations of MIP-1beta, the CCR5 agonist, were twice as high in sCCR5-positives (140.8+/-25.8 pg/ml) as in the sCCR5-negatives (77.6+/-11.0 pg/ml, P=0.0157). A significant positive correlation between plasma levels of sCCR5 and MIP-1beta was found (Fig. 4, r=0.8, P<0.0001).

Immunity, immunoregulation and the ecology of trichuriasis and ascariasis

Immune responses to human roundworm (Ascaris lumbricoides) and whipworm (Trichuris trichiura) and their role in controlling worm populations are reviewed. Recent immunoepidemiological data implicate T(H)2-mediated responses in limiting A. lumbricoides and T. trichiura populations. Reinfection studies further suggest that IL-5 cytokine responses are negatively associated with adult recruitment in T. trichiura but not A. lumbricoides and may therefore be involved in negative intraspecific and interspecific interactions mediated through the host immune system. The importance of inducible immunoregulatory networks in the ecology of the host-parasite relationship is considered, with particular regard to possible manipulative strategies by the parasites. This aspect of the worms' interaction with the host immune system is both poorly known and potentially central to an understanding of parasite population dynamics and the evolutionary pressures that have shaped present-day host-parasite associations. Some possible implications of worm-mediated immunomodulation for the occurrence of bystander infectious diseases in human populations and the management of de-worming programmes are also discussed.

Chronic immune activation associated with chronic helminthic and human immunodeficiency virus infections: role of hyporesponsiveness and anergy

Chronic immune activation is one of the hallmarks of human immunodeficiency virus (HIV) infection. It is present also, with very similar characteristics, in very large human populations infested with helminthic infections. We have tried to review the studies addressing the changes in the immune profiles and responses of hosts infected with either one of these two chronic infections. Not surprisingly, several of the immune derangements and impairments seen in HIV infection, and considered by many to be the "specific" effects of HIV, can be found in helminth-infected but HIV-noninfected individuals and can thus be accounted for by the chronic immune activation itself. A less appreciated element in chronic immune activation is the immune suppression and anergy which it may generate. Both HIV and helminth infections represent this aspect in a very wide and illustrative way. Different degrees of anergy and immune hyporesponsiveness are present in these infections and probably have far-reaching effects on the ability of the host to cope with these and other infections. Furthermore, they may have important practical implications, especially with regard to protective vaccinations against AIDS, for populations chronically infected with helminths and therefore widely anergic. The current knowledge of the mechanisms responsible for the generation of anergy by chronic immune activation is thoroughly reviewed.

Elevation of Immune Activation in Kenyan Women is Associated with Alterations in Immune Function: Implications for Vaccine Development

The infectious burden leading to immune activation can vary between different populations and lead to various immune dysfunctions. We compared the effect of immune activation on apoptosis and T cell function in HIV uninfected individuals from Nairobi, Kenya (n=34), and Winnipeg, Canada (n=10). Women from Nairobi had a significantly greater number of CD8+ T cells expressing the activation markers CD38 and HLA DR. Kenyan women also had significantly higher levels of CTLA-4+ CD4 and CD8+ T cells, and reduced levels of CD28+ CD8+ cells. Levels of CD95+ CD4+ T cells were higher in Kenyan women and, correspondingly, showed higher levels of spontaneous apoptosis. Kenyan women also demonstrated hyper-responsiveness to T cell activation as assessed by interferon gamma production. This study demonstrates that in a population of Kenyan women with high levels of T cell activation, there were also elevated levels of T cell apoptotic death and hyper-responsiveness. These differences may influence the efficacy of immune responses to pathogens and must be considered when testing candidate vaccines.

Immunophenotyping of blood lymphocytes at birth, during childhood, and during adulthood in HIV-1-uninfected Ethiopians

To obtain more insight into blood lymphocyte subpopulations of Ethiopians, we studied the immunologic profile of children and neonates and compared these data with those obtained from adults. Peripheral blood mononuclear cells (PBMCs) and cord blood mononuclear cells (CBMCs) were collected from 137 HIV-1-uninfected subjects aged 0 (cord blood) up to 40 years. Lymphocyte subsets (T, B, and NK cells, CD4+ and CD8+ T cells) were determined and T cell activation (CD38 and HLA-DR) and differentiation (CD45RO and CD27) markers were measured on CD4+ and CD8+ T cells. The absolute number and percentage values of most lymphocyte subpopulations differed substantially with age. Neonates and children were found to have significantly higher CD4+ T cell counts compared to adults. The median absolute CD4 count at birth was comparable to those reported for Caucasians. At birth 97% of the CD4+ T cells were naîve and this proportion significantly declined to 14.2% during adulthood. In addition, activation of both CD4+ and CD8+ T cells, as determined by the double expression of HLA-DR and CD38, was observed in children under the age of 16 and adults, but not in neonates. A more differentiated phenotype (CD27-) was observed in adults compared to children for both CD4+ and CD8+ T cells. The immune alterations including the remarkably low CD4 count with highly depleted naîve phenotype and a persistently activated immune system seen in adult Ethiopians are not apparent at birth, but rather develop over time.

Replication of HIV-1 deleted Nef mutants in chronically immune activated human T cells

Lymphocytes (PBMC) obtained from blood of HIV-sera negative Ethiopian immigrants (ETH) were highly susceptible to HIV-1 infection in vitro with no need for stimulation by mitogens. As the HIV nef gene product has been shown to enhance viral replication in stimulated primary lymphocytes, we investigated in this work the role of Nef in viral replication in the ETH cells. Lymphocytes obtained from ETH individuals supported high replication of wild-type HIV-1 and low but significant replication level of the two deleted Nef mutants (encode truncated Nef proteins consisting only of either the first 35 or the first 86 amino acids of Nef). In contrast, no replication was observed in nonactivated cells obtained from non-ETH individuals. After activation of the PBMC from ETH individuals with PHA, replication of both wild-type strains and the two deleted Nef mutant viruses further increased. The CD4(+) T cells of ETH individuals exhibited elevated levels of the surface activation markers CD45RO and HLA-DR, compared with T cells derived from non-ETH group. Likewise, expression of the chemokine receptors CCR5 and CXCR4 on these cells was higher in the ETH group than in the non-ETH group. Replication of HIV-1 wild-type and the isogenic-deleted Nef mutants was significantly correlated with the proportion of ETH cells expressing CD45RO and the chemokine receptors. This study suggests that HIV-1 may respond differently to several activation states characteristic of T cells. One activation state, defined by chronically activated lymphocytes from ETH individuals, is permissive to the wild-type HIV-1 and, to a lesser degree, to the Nef mutants. Further activation of these cells by exogenous stimuli enhances replication of the virus. Our results support the notion that Nef enhances the basal level of T cell activation and consequently, viral replication.

Treatment of intestinal worms is associated with decreased HIV plasma viral load

BACKGROUND

We have previously suggested that helminthic infections make the host more susceptible to HIV infection and enhance its progression due to the chronic immune activation they cause.

OBJECTIVE

To study the effect of antihelminthic treatment on HIV plasma viral load (VL) in HIV- and helminth-infected individuals living in Ethiopia.

METHODS

Fifty-six clinically asymptomatic HIV-1-infected individuals, 31 (55%) of whom were also infected with helminths, were studied. All participants received antihelminthic treatment at baseline and at 3 and 6 months. Worm egg excretion, HIV plasma VL, and T-cell subsets were determined at baseline and 6 months after treatment.

RESULTS

The mean age, number of CD4 T cells, and gender distribution were similar in the helminth-infected and -noninfected groups. At baseline, HIV plasma VL was strongly correlated to the number of eggs excreted (p <.001) and was higher in individuals infected with more than one helminth (5.28 +/- 0.35 versus 4.30 +/- 1.13 log RNA copies/mL, respectively; p =.16). After treatment of helminths, the 6-month change in HIV plasma VL was significantly different between the successfully treated group and the persistently helminth-positive group (p =.04)

CONCLUSIONS

Helminth "load" is correlated to HIV plasma VL, and successful deworming is associated with a significant decrease in HIV plasma VL. The results of the current study, if confirmed in a larger study, may have important implications for slowing disease progression and reducing risks of transmission.

Human retroviruses after 20 years: a perspective from the past and prospects for their future control

Among viruses the human retroviruses may be of special interest to immunologists, because they target cells of the immune system, particularly mature CD4+ T cells, impair their function and cause them to grow abnormally (human T-cell leukemia virus, HTLV) or to die (human immunodeficiency virus, HIV). Human retroviruses cause disease ranging from neurological disorders and leukemias (HTLV-1) to AIDS (acquired immunodeficiency virus) (HIV) and promote development of several types of malignancies (HIV). They share many common features, but their contrasts are greater, especially the far greater replication and variation of HIV associated with its greater genomic complexity. Both have evolved striking redundancy for mechanisms which promote their survival. Thus, HTLV has redundant mechanisms for promoting growth of provirus containing T cells needed for virus continuity, because it is chiefly through its cellular DNA provirus that HTLV replicates and not through production of virions. Conversely, HIV has redundancy in its mechanisms for promoting virion replication and escape from the host immune system. It is via these redundant mechanisms that they produce disease: leukemias from mechanisms promoting T-cell proliferation (HTLV-1) and AIDS from mechanisms promoting virus replication and T-cell death (HIV). The practical challenges for the future are clear. For HTLV-1, education and control of breastfeeding. For HIV, the formidable tasks now ahead in part demand new kinds of talent, talents that will foster greater insights into the development of therapy for the developing countries, new forms of less toxic therapies for all infected persons, a continued and expanded commitment to education, and a persistent 'never say die' commitment to the development of a truly preventive vaccine with all the scientific and nonscientific challenges that these objectives face.