Helicobacter pylori Coinfection Is Associated With Decreased Markers of Immune Activation in ART-Naive HIV-Positive and in HIV-Negative Individuals in Ghana

Human immunodeficiency virus and Helicobacter pylori coinfection: Immune modulation and eradication failure

The relationship between Human Immunodeficiency Virus (HIV) and Helicobacter pylori (H. pylori) is bidirectional and complex. Helicobacter pylori, by inducing local gastric and systemic immune responses, counteracts HIV invasion to CD4+ cells and other inflammatory cells and can reactivate HIV in latently infected immune cells. Human Immunodeficiency Virus infection, by reducing secretion of pro-inflammatory cytokines, reduces the incidence of H. pylori-induced gastric pathology. Gastric lymphoma regressed in some cases of people living with HIV (PLWH) after H. pylori eradication. Triple therapy for H. pylori could be associated with a strong immune. Treatment for both H. pylori and HIV can reduce the activation of either organism. However, the primary resistance to antibiotics such as levofloxacin, clarithromycin and metronidazole is higher among PLWH. This review highlights the need for further research and guidelines on the appropriate antibiotics in HIV-H. pylori co-infection particularly in PLWH who receive multiple antibiotic prophylaxis.

Epidemiological, Clinical, and Immunological Features of Ghanaian People-Living-with-HIV (Human Immunodeficiency Virus) and Molecular Proof of Cystoisospora belli in Their Stool Samples

Cystoisospora belli is a coccidian parasite commonly associated with enteric infections in immunocompromised individuals. The study was conducted to assess epidemiological, clinical, and immunological features of Ghanaian people living with HIV (human immunodeficiency virus) with and without antiretroviral therapy and molecular proof of C. belli-specific nucleic acid sequences in their stool samples. While C. belli was detected in 4.2% (n = 25) of the assessed HIV-positive patients, this was the case for only 1 (1.2%) Ghanaian control individuum without known HIV infection. Associations of cystoisosporiasis in Ghanaian HIV patients with reduced CD4+ T-lymphocyte counts and increased HIV viral loads, immune-activation as indicated by reduced CD4+/CD8+ T-lymphocyte ratios as well as higher expression of HLA-DR+ CD38+ on CD4+ T-lymphocytes, a symptom complex comprising diarrhea, weight loss and a reduced BMI, a trend towards not being on antiretroviral medication, and lacking access to food safety procedures like storing food in refrigerators were shown. The odds ratios (95% confidence intervals) of the associations were 4.47 (1.52-12.09) for the abundance of C. belli DNA and clinical diarrhea, 3.51 (1.42-9.12) for the abundance of C. belli DNA and CD4+ T-lymphocyte counts <200 cells/µL, and 3.66 (1.52-9.01) for the abundance of C. belli DNA and not having a refrigerator in the household. In conclusion, the assessment contributed to existing insight into the epidemiology of cystoisosporiasis in immunosuppressed individuals in resource-limited tropical high-endemicity areas. Chronic diarrhea among people living with HIV should prompt a diagnostic assessment for confirmation or exclusion of C. belli infections in such settings.

Association of Molecular Detections of Microsporidia in Stool Samples with Clinical and Immunological Parameters in Ghanaian HIV Patients

Although the etiological relevance of the detection of microsporidia in human stool samples remains uncertain, the immunological status of patients has been posited as an important determinant of potential clinical impact of these parasites. To further assess the interplay between the epidemiology of microsporidia and immunological markers, we conducted a study utilizing real-time PCR targeting Enterocytozoon bieneusi, Encephalitozoon cuniculi, Encephalitozoon hellem, and Encephalitozoon intestinalis, combined in a single fluorescence channel. The study involved a cohort of 595 clinically and immunologically well-characterized Ghanaian HIV patients, alongside 82 HIV-negative control individuals from Ghana. While microsporidial DNA was absent in HIV-negative controls, among people living with HIV, its prevalence was inversely correlated with CD4+ lymphocyte counts: 6.0% in those with >500 cells/µL, 9.5% in those with 200-499 cells/µL, 13.8% in those with 50-199 cells/µL, and 27.5% in those with <50 cells/µL, respectively. Correspondingly, microsporidia were more frequently detected in HIV patients who were not receiving antiretroviral therapy. There were no associations with clinical symptoms including gastroenteritis with the exception of a non-significant trend towards weight loss. HLA-DR+CD38+ on CD4+ T lymphocytes, a marker of immune activation, as well as Ki67, a marker of cell proliferation, were increased on CD4+ T lymphocytes in HIV patients with microsporidia, suggesting an immune response may be triggered. In conclusion, our assessment indicates a higher prevalence of microsporidia in the stool of Ghanaian HIV patients, which varies with their immunological status. However, given the lack of clear associations with clinical symptoms, the detection of microsporidia in the stool of HIV patients needs to be cautiously interpreted in clinical settings.

Clustering of Gastrointestinal Microorganisms in Human Stool Samples from Ghana

The study was conducted to identify cluster patterns of enteric microorganisms with potential etiological relevance for infectious gastroenteritis in stool samples of individuals from Ghana, which is a known high-endemicity setting for infectious gastroenteritis. These patterns were compared to previous observations with specimens from Colombian indigenous people in order to assess potentially stable clustering for temporally and spatially distinct populations from high-endemicity regions. By doing so, the study aimed to identify stable clusters as markers of microbial interaction with potential importance for etiological relevance assignment in cases of multiple enteric pathogen detections. Stool samples from 1569 Ghanaian individuals (875 from HIV patients, 30 from HIV-negative control adult patients, and 644 from children < 2 years of age) were assessed for enteric microorganisms by applying real-time PCR. As a result, nucleic acids of bacterial microorganisms were most frequently detected, followed by protozoa, microsporidia, and helminths. Interestingly, the cluster assessment confirmed interaction patterns known from the previous analysis with Colombian indigenous people, demonstrating a high likelihood of Blastocystis hominis for clustering with other microorganisms and a prominent, potentially mediating role of Dientamoeba fragilis for microbial interactions within the clusters. In conclusion, the assessment confirmed conserved clustering of enteric microorganisms with potential etiological relevance for human infectious gastroenteritis over geographically distinct high-endemicity settings. Furthermore, the composition of abundant microorganisms is more important than regional factors for the determination of the interplay of enteric microorganisms in the human gut. Thereby, some microbial pathogens and commensals seem more susceptible to a changing microbial composition in the human gut than others.

CD4+ T cell count and HIV-1 viral load dynamics positively impacted by H. pylori infection in HIV-positive patients regardless of ART status in a high-burden setting

BACKGROUND

There is a widespread co-infection of HIV and Helicobacter pylori (H. pylori) globally, particularly in developing countries, and it has been suggested that this co-infection may affect the course of HIV disease. However, the interplay between H. pylori infection and HIV disease progression is not fully elucidated. In this study, we investigated the effect of H. pylori co-infection on CD4+ T cell count and HIV viral load dynamics in HIV-positive individuals in a high co-endemic setting.

METHODS

A comparative cross-sectional study was conducted among 288 HIV-positive and 175 HIV-negative individuals, both with and without H. pylori infection. Among HIV-positive participants, 195 were on antiretroviral therapy (ART) and 93 were ART-naïve. CD4+ T cell count and HIV-1 viral load were measured and compared between H. pylori-infected and -uninfected individuals, taking into account different HIV and ART status.

RESULT

Our study demonstrated that individuals infected with H. pylori had a significantly higher CD4+ T cell count compared to uninfected controls among both HIV-negative and HIV-positive participants, regardless of ART therapy. Conversely, HIV/H. pylori co-infected participants had lower HIV-1 viral load than those without H. pylori infection. Linear regression analysis further confirmed a positive association between H. pylori infection, along with other clinical factors such as BMI, ART, and duration of therapy, with CD4+ T cell count while indicating an inverse relationship with HIV-1 viral load in HIV-positive patients. Additionally, factors such as khat chewing, age and WHO clinical stage of HIV were associated with reduced CD4+ T cell count and increased HIV-1 viral load.

CONCLUSION

Our study demonstrates that H. pylori co-infection was associated with higher CD4+ T cell count and lower HIV-1 viral load in HIV-positive patients, regardless of ART status. These findings show a positive effect of H. pylori co-infection on the dynamics of HIV-related immunological and virological parameters. Further studies are needed to elucidate the underlying mechanisms of the observed effects.

Comparison of the Diagnostic Accuracy of Three Real-Time PCR Assays for the Detection of Arcobacter butzleri in Human Stool Samples Targeting Different Genes in a Test Comparison without a Reference Standard

Potential etiological relevance for gastroenteric disorders including diarrhea has been assigned to Arcobacter butzleri. However, standard routine diagnostic algorithms for stool samples of patients with diarrhea are rarely adapted to the detection of this pathogen and so, A. butzleri is likely to go undetected unless it is specifically addressed, e.g., by applying pathogen-specific molecular diagnostic approaches. In the study presented here, we compared three real-time PCR assays targeting the genes hsp60, rpoB/C (both hybridization probe assays) and gyrA (fluorescence resonance energy transfer assay) of A. butzleri in a test comparison without a reference standard using a stool sample collection with a high pretest probability from the Ghanaian endemicity setting. Latent class analysis was applied with the PCR results obtained with a collection of 1495 stool samples showing no signs of PCR inhibition to assess the real-time PCR assays' diagnostic accuracy. Calculated sensitivity and specificity were 93.0% and 96.9% for the hsp60-PCR, 100% and 98.2% for the rpoB/C-PCR, as well as 12.7% and 99.8% for the gyrA-PCR, respectively. The calculated A. butzleri prevalence within the assessed Ghanaian population was 14.7%. As indicated by test results obtained with high-titer spiked samples, cross-reactions of the hsp60-assay and rpoB/C-assay with phylogenetically related species such as A. cryaerophilus can occur but are less likely with phylogenetically more distant species like, e.g., A. lanthieri. In conclusion, the rpoB/C-assay showed the most promising performance characteristics as the only assay with sensitivity >95%, albeit associated with a broad 95%-confidence interval. In addition, this assay showed still-acceptable specificity of >98% in spite of the known cross-reactivity with phylogenetically closely related species such as A. cryaerophilus. If higher certainty is desired, the gyrA-assay with specificity close to 100% can be applied for confirmation testing with samples showing positive rpoB/C-PCR results. However, in case of a negative result in the gyrA-assay, this cannot reliably exclude the detection of A. butzleri in the rpoB/C-assay due to the gyrA-assay's very low sensitivity.

Seroprevalence of Helicobacter pylori in human immunodeficiency virus-infected patients in a tertiary care hospital in Busan, South Korea

INTRODUCTION

Human immunodeficiency virus (HIV) infection management has recently become more successful. While the life expectancy of HIV-infected patients increased, the prevalence of non-acquired immunodeficiency syndrome-defining cancers, such as gastric cancer, also increased. Helicobacter pylori is associated with gastric cancer, the most common cancer and the fourth leading cause of cancer-related deaths in South Korea, which has the highest incidence of chronic gastric mucosa inflammation. Here, the seroprevalence and risk factors of H. pylori infection in Korean HIV-infected patients were evaluated.

METHODS

Three hundred HIV-infected patients attending the Outpatient Department of Pusan National University Hospital were prospectively enrolled from October 2018 to February 2019. Socio-demographic information was evaluated using questionnaires, and the serological status of H. pylori infection was analyzed for anti-H. pylori IgG antibodies.

RESULTS

The overall seropositivity of H. pylori was 32.7%, and 254 patients (84.7%) were male. The risk factors significantly associated with H. pylori seropositivity were: age of 40-49 years (odds ratio [OR] = 5.00; 95% confidence interval [CI] 1.30-19.17), age of 50-59 years (OR = 3.93; 95% CI 1.05-14.73), CD4 cell counts of 350-500/μL (OR = 4.23; 95% CI 1.53-11.65), CD4 cell counts ≥500/μL (OR = 2.78; 95% CI 1.15-6.72), and a weekly average alcohol consumption of at least one alcoholic beverage (OR = 1.78; 95% CI 1.05-2.99).

CONCLUSIONS

The seroprevalence of H. pylori is significantly associated with alcohol consumption, high CD4 cell count, and the age group of 40-59 years.

The Clinical Features and Immunological Signature of Cyclospora cayetanensis Co-Infection among People Living with HIV in Ghana

Background: There is a paucity of information on the contemporary burden, disease patterns, and immunological profile of people living with HIV who are co-infected with C. cayetanensis in the post-antiretroviral therapy era. Methods: For this cross-sectional study, stool samples of 640 HIV-positive and 83 HIV-negative individuals in Ghana were tested for C. cayetanensis. Additionally, sociodemographic parameters, clinical symptoms, medical drug intake, and immunological parameters were assessed. Results: The prevalence of C. cayetanensis was 8.75% (n = 56) in HIV-positive and 1.20% (n = 1) in HIV-negative participants (p = 0.015). Within the group of HIV-positive participants, the prevalence reached 13.6% in patients with CD4+ T cell counts below 200 cells/µl. Frequencies of the clinical manifestations of weight loss and diarrheal disease were significantly higher in patients with C. cayetanensis compared to those without co-infection (36.36% vs. 22.59%, p = 0.034 and 20.00% vs. 4.90%, p < 0.001, respectively). The expression of markers of immune activation and exhaustion of T lymphocyte sub-populations was significantly elevated in patients colonized with C. cayetanensis. Conclusions: In the modern post-combined antiretroviral therapy (cART) era, the acquisition of C. cayetanensis among PLWH in Ghana is driven largely by the immunosuppression profile characterized by high expression of markers of immune activation and immune exhaustion.

Screening for Schistosoma spp. and Leishmania spp. DNA in Serum of Ghanaian Patients with Acquired Immunodeficiency

Both Schistosoma spp. (species) and Leishmania spp. are prevalent in Ghana in West Africa. However, little is known about their local occurrence in immunocompromised individuals. In the study presented here, the real-time PCR-(polymerase chain reaction-)based screening for repetitive DNA (deoxyribonucleotide acid) sequences from the genomes of Leishmania (L.) spp. and Schistosoma (S.) spp. was performed in the serum of HIV-(human immunodeficiency virus-)infected Ghanaian patients. In 1083 assessed serum samples from HIV-positive and HIV-negative Ghanian patients, Leishmania spp.-specific DNA was not detected, while the diagnostic accuracy-adjusted prevalence estimation suggested a 3.6% prevalence of the S. mansoni complex and a 0.5% prevalence of the S. haematobium complex. Associations of schistosomiasis with younger age, as well as with the male sex, could be shown but not with an HIV status. Weakly significant signals for the associations of schistosomiasis with an increased viral load, reduced CD4+ (CD = cluster of differentiation) T cell count, and a reduced CD4+/CD8+ ratio could be observed but was inconsistently lost in the case of the stratification on the species complex level. So, it is concluded that factors other than HIV status are more likely to have influenced the occurrence of Schistosoma spp. infections in the assessed Ghanaian patients. Potential associations between HIV infection-associated factors, such as the viral load and the immune status of the patients, for which weak signals were observed in this hypothesis-forming retrospective assessment, should be confirmed by prospective, sufficiently powered investigations.

Comparative Evaluation of Real-Time Screening PCR Assays for Giardia duodenalis and of Assays Discriminating the Assemblages A and B

Due to superior sensitivity compared to traditional microscopy, real-time PCR has been well established for the diagnosis of Giardia duodenalis in human stool samples. In this study, screening real-time PCRs for different target genes of G. duodenalis, i.e., the 18S rRNA gene, the gdh (glutamate dehydrogenase) gene and the bg (beta-giardin) gene, were comparatively assessed next to various real-time PCR assays for the discrimination of the assemblages A and B of G. duodenalis targeting the bg gene with and without locked nucleic acid–containing probes as well as the tpi (triose phosphate isomerase) gene. The screening PCRs were assessed by including 872 non-preselected samples with a high pre-test probability for G. duodenalis in the statistical analysis, while 53 G. duodenalis-positive samples as indicated by at least two screening PCRs were finally included in the assessment of the assemblage-specific PCRs. For the screening PCRs, sensitivity estimated with latent class analysis (LCA) ranged from 17.5% to 100%, specificity from 92.3% to 100% with an accuracy-adjusted prevalence of 7.2% for G. duodenalis within the non-preselected sample collection. In detail, sensitivity and specificity were 100% and 100% for the 18S rRNA gene-specific assay, 17.5% and 92.3% for the gdh gene-specific assay, and 31.7% and 100% for the bg gene-specific assay, respectively. Agreement kappa was slight with only 15.5%. For the assemblage-specific PCRs, estimated sensitivity ranged from 82.1% to 100%, specificity from 84.0% to 100% with nearly perfect agreement kappa of 90.1% for assemblage A and yet substantial agreement of 74.8% for assemblage B. In detail for assemblage A, sensitivity and specificity were 100% and 100% for the bg gene-specific assay without locked nucleic acids (LNA) as well as 100% and 97.8% for both the bg gene-specific assay with LNA and the tri gene-specific assay, respectively. For assemblage B, sensitivity and specificity were 100% and 100% for the bg gene-specific assay without LNA, 96.4% and 84.0% for the bg gene-specific assay with LNA, and 82.1% and 100% for the tri gene-specific assay, respectively. Within the assessed sample collection, the observed proportion comprised 15.1% G. duodenalis assemblage A, 52.8% G. duodenalis assemblage B and 32.1% non-resolved assemblages. Only little differences were observed regarding the cycle threshold (Ct) values when comparing the assays. In conclusion, best diagnostic accuracy was shown for an 18S rRNA gene-specific screening assay for G. duodenalis and for a differentiation assay discriminating the G. duodenalis assemblages A and B by targeting the bg gene with probes not containing locked nucleic acids. By adding additional highly specific competitor assays for confirmation testing, diagnostic specificity can be further increased on the cost of sensitivity if optimized specificity is desired.

Multicentric Evaluation of SeeGene Allplex Real-Time PCR Assays Targeting 28 Bacterial, Microsporidal and Parasitic Nucleic Acid Sequences in Human Stool Samples

Prior to the implementation of new diagnostic techniques, a thorough evaluation is mandatory in order to ensure diagnostic reliability. If positive samples are scarcely available, however, such evaluations can be difficult to perform. Here, we evaluated four SeeGene Allplex real-time PCR assays amplifying a total of 28 bacteria, microsporidal and parasitic nucleic acid sequence targets in human stool samples in a multicentric approach. In the assessments with strongly positive samples, sensitivity values ranging between 13% and 100% were recorded for bacteria, between 0% and 100% for protozoa and between 7% and 100% for helminths and microsporidia; for the weakly positive samples, the recorded sensitivity values for bacteria ranged from 0% to 100%; for protozoa, from 0% to 40%; and for helminths and microsporidia, from 0% to 53%. For bacteria, the recorded specificity was in the range between 87% and 100%, while a specificity of 100% was recorded for all assessed PCRs targeting parasites and microsporidia. The intra- and inter-assay variations were generally low. Specifically for some helminth species, the sensitivity could be drastically increased by applying manual nucleic acid extraction instead of the manufacturer-recommended automatic procedure, while such effects were less obvious for the bacteria and protozoa. In summary, the testing with the chosen positive control samples showed varying degrees of discordance between the evaluated Allplex assays and the applied in-house reference assays associated with higher cycle threshold values in the Allplex assays, suggesting that samples with very low pathogen densities might be missed. As the targeted species can occur as harmless colonizers in the gut of individuals in high-endemicity settings as well, future studies should aim at assessing the clinical relevance of the latter hint.

Comparison of Three Real-Time PCR Assays for the Detection of Cyclospora cayetanensis in Stool Samples Targeting the 18S rRNA Gene and the hsp70 Gene

Diagnostic real-time PCR for the detection of Cyclospora cayetanensis in human stool samples has been applied for two decades. However, recent comparative assessments between in-house and commercial assays suggested room for improvement regarding the agreement of positive signals of the applied real-time PCRs. In order to assess the effect of the choice of the target sequence, 3 inhouse real time PCR assays targeting the 18S rRNA gene (n = 2, one of them later referred to as SSU rRNA gene assay to avoid confusion) and the hsp70 gene of C. cayetanensis were compared in a head-to-head comparison with 905 samples with high pretest probability for C. cayetanensis infections from Ghanaian HIV patients in a test comparison without a reference standard. Only slight agreement kappa of 0.095 was observed. In the assays targeting the SSU rRNA gene, the 18S rRNA gene, and hsp70, positive signals were recorded in 63, 45, and 0 instances, respectively, with latent class analysis-based estimation of sensitivity of 32.2%, 23.3%, 0% as well as of specificity of 99.7%, 99.9% and 100%, respectively. High cycle threshold values with an average of about 35 indicated low quantities of target DNA in the samples with similar Ct values in concordantly and discordantly positive samples. In conclusion, the study suggested target-gene-specific differences in the diagnostic accuracy of real-time PCR-based diagnosis of C. cayetanensis as well as an ongoing need for further standardization of this diagnostic approach.

Comparison of Three Real-Time PCR Assays Targeting the SSU rRNA Gene, the COWP Gene and the DnaJ-Like Protein Gene for the Diagnosis of Cryptosporidium spp. in Stool Samples

As qualified microscopy of enteric parasitoses as defined by high diagnostic accuracy is difficult to maintain in non-endemic areas due to scarce opportunities for practicing with positive sample materials, molecular diagnostic options provide less investigator-dependent alternatives. Here, we compared three molecular targets for the real-time PCR-based detection of Cryptosporidium spp. From a population of 1000 individuals comprising both Ghanaian HIV (human immunodeficiency virus) patients and military returnees after deployment in the tropics, stool samples were assessed for Cryptosporidium spp. by real-time PCR targeting the small subunit ribosomal RNA (SSU rRNA) gene, the Cryptosporidium oocyst wall (COWP) gene, and the DnaJ-like protein gene (DnaJ), respectively. In declining order, sensitivity of 100% for the SSU rRNA gene PCR, 90.0% for the COWP PCR and 88.8% for the DnaJ PCR, respectively, as well as specificity of 99.6% for the COWP PCR and 96.9% for both the SSU rRNA gene PCR and the DnaJ PCR, respectively, were recorded. Substantial agreement (kappa value 0.663) between the three assays was observed. Further, an accuracy-adjusted Cryptosporidium spp. prevalence of 6.0% was calculated for the study population. In conclusion, none of the assessed real-time PCR assays were associated with perfect test accuracy. However, a combination of highly sensitive SSU rRNA gene PCR for screening purposes and more specific COWP PCR for confirmatory testing should allow reliable diagnosis of Cryptosporidium spp. in stool samples even in low prevalence settings.

Intestinal Colonization with Tropheryma whipplei-Clinical and Immunological Implications for HIV Positive Adults in Ghana

BACKGROUND

Recent studies demonstrated higher prevalence rates of Tropheryma whipplei (T. whipplei) in HIV positive than in HIV negative subjects. However, associations with the immune status in HIV positive participants were conflicting.

METHODS

For this cross-sectional study, stool samples of 906 HIV positive and 98 HIV negative individuals in Ghana were tested for T. whipplei. Additionally, sociodemographic parameters, clinical symptoms, medical drug intake, and laboratory parameters were assessed.

RESULTS

The prevalence of T. whipplei was 5.85% in HIV positive and 2.04% in HIV negative participants. Within the group of HIV positive participants, the prevalence reached 7.18% in patients without co-trimoxazole prophylaxis, 10.26% in subjects with ART intake, and 12.31% in obese participants. Frequencies of clinical symptoms were not found to be higher in HIV positive T. whipplei carriers compared to T. whipplei negative participants. Markers of immune activation were lower in patients colonized with T. whipplei. Multivariate regression models demonstrated an independent relationship of a high CD4+ T cell count, a low HIV-1 viral load, and an obese body weight with the presence of T. whipplei.

CONCLUSIONS

Among HIV positive individuals, T. whipplei colonization was associated with a better immune status but not with clinical consequences. Our data suggest that the withdrawal of co-trimoxazole chemoprophylaxis among people living with HIV on stable cART regimen may inadvertently increase the propensity towards colonization with T. whipplei.

Comparison of Two Real-Time PCR Assays Targeting Ribosomal Sequences for the Identification of Cystoisospora belli in Human Stool Samples

Cystoisospora (C.) belli is a coccidian parasite associated with acute or chronic gastroenteritis in immunocompromised patients. Dissatisfactory sensitivity of microscopy as the diagnostic standard approach has been described. Here, we comparatively evaluated two real-time PCRs targeting ribosomal RNA gene sequences of C. belli in stool in a test comparison without a reference standard applying latent class analysis. Therefore, 1000 stool samples from Ghanaian HIV (human immunodeficiency virus) patients (n = 905) as well as military returnees from the tropics (n = 95) were assessed by both assays in parallel. After the exclusion of 33 samples showing PCR inhibition, 29 and 33 positive results were recorded with the 5.8S rRNA gene/ITS-2 sequence PCR and the ITS-2 sequence PCR, respectively, resulting in an accuracy-adjusted prevalence of 3.2%. Nearly perfect agreement between both assays was indicated by Fleiss’ kappa of 0.933 with sensitivity and specificity of 92.8% and 100% as well as 100% and 99.8% for the 5.8S rRNA gene/ITS-2 sequence PCR and the ITS-2 sequence PCR, respectively. Both assays proved to be suitable for the diagnosis of C. belli in human stool samples with slightly better sensitivity of the ITS-2 sequence assay, while the 5.8S rRNA gene/ITS-2 sequence PCR may be considered for confirmatory testing.

Effect of Helicobacter pylori and Helminth Coinfection on the Immune Response to Mycobacterium tuberculosis

Tuberculosis remains one of the main causes of morbidity and mortality worldwide despite decades of efforts to eradicate the disease. Although the immune response controls the infection in most infected individuals (90%), the ability of the bacterium to persist throughout the host's life leads to a risk of reactivation. Underlying conditions including human immunodeficiency virus (HIV) infection, organ transplantation, and immunosuppressive therapies are considered risk factors for progression to active disease. However, many individuals infected with Mycobacterium tuberculosis may develop clinical disease in the absence of underlying immunosuppression. It is also possible that unknown conditions may drive the progression to disease. The human microbiota can be an important modulator of the immune system; it can not only trigger inflammatory disorders, but also drive the response to other infectious diseases. In developing countries, chronic mucosal infections with Helicobacter pylori and helminths may be particularly important, as these infections frequently coexist throughout the host's life. However, little is known about the interactions of these pathogens with the immune system and their effects on M. tuberculosis clinical disease, if any. In this review, we discuss the potential effects of H. pylori and helminth co-infections on the immune response to M. tuberculosis. This may contribute to our understanding of host-pathogen interactions and in designing new strategies for the prevention and control of tuberculosis.

Comparative Assessment of In-House Real-Time PCRs Targeting Enteric Disease-Associated Microsporidia in Human Stool Samples

Microsporidiosis is an infection predominantly occurring in immunosuppressed patients and infrequently also in travelers. This study was performed to comparatively evaluate the diagnostic accuracy of real-time PCR assays targeting microsporidia with etiological relevance in the stool of human patients in a latent class analysis-based test comparison without a reference standard with perfect accuracy. Thereby, two one-tube real-time PCR assays and two two-tube real-time PCR assays targeting Enterocytozoon bieneusi and Encephalocytozoon spp. were included in the assessment with reference stool material (20), stool samples from Ghanaian HIV-positive patients (903), and from travelers, migrants and Colombian indigenous people (416). Sensitivity of the assays ranged from 60.4% to 97.4% and specificity from 99.1% to 100% with substantial agreement according to Cohen’s kappa of 79.6%. Microsporidia DNA was detected in the reference material and the stool of the HIV patients but not in the stool of the travelers, migrants, and the Colombian indigenous people. Accuracy-adjusted prevalence was 5.8% (n = 78) for the study population as a whole. In conclusion, reliable detection of enteric disease-associated microsporidia in stool samples by real-time PCR could be demonstrated, but sensitivity between the compared microsporidia-specific real-time PCR assays varied.

Gut-Homing CD4+ T Cells Are Associated with the Activity of Gastritis in HIV-Infected Adults

Previous studies have shown that HIV-infected individuals were less susceptible to chronic gastritis and Helicobacter pylori infection. Th1 and Th17 cells are important components of the immune response to H. pylori in adults. We investigated the relative importance of Th1 versus Th17 responses for mucosal inflammation and protection. We conducted a prospective cross-sectional study to evaluate the relationship among the peripheral blood gut-homing CD4⁺ T cell subset, the severity of chronic H. pylori gastritis, and H. pylori amount in the gastric mucosa. Biopsy specimens were obtained at the time of gastroendoscopy, which was used for classification of histological gastritis by updated-Sydney system. Peripheral blood mononuclear cells were collected at the same point to determine the frequency of peripheral blood gut homing CD4⁺ T cells (CCR9⁺integrin β₇⁺) and CD4⁺ memory T cells subsets by flow cytometry. H. pylori amount in the gastric mucosa was measured using 16S ribosomal RNA gene amplicon sequencing. Peripheral blood gut-homing CD4⁺ T cells were significantly higher in individuals with histological gastritis compared with those without chronic gastritis (median 16.8 cells/μL vs. 9.7 cells/μL; p = .0307). In particular, there were significant differences in gut-homing Th1 (median 1.3 cells/μL vs. 0.5 cells/μL; p = .0061) and nonconventional Th1 (median 0.4 cells/μL vs. 0.2 cells/μL; p = .0196). In addition, there was a significant positive correlation between H. pylori amount in the gastric mucosa measured using 16S ribosomal RNA gene amplicon sequencing and gut-homing Th1 subsets. Our findings suggested that gut Th1 may play a key role in the development of chronic gastritis in HIV-infected individuals.

Molecular Characterization and Clinical Description of Non-Polio Enteroviruses Detected in Stool Samples from HIV-Positive and HIV-Negative Adults in Ghana

In the post-polio eradication era, increasing attention is given to non-polio enteroviruses. Most of the data about enteroviruses in sub-Saharan Africa are related to acute flaccid paralysis surveillance and target the pediatric population. This study aimed to investigate the presence of enterovirus in PLHIV (people living with HIV) and HIV-negative individuals in Ghana. Stool samples from HIV-positive individuals (n = 250) and healthy blood donors (n = 102) attending the Komfo Anokye Teaching Hospital in Kumasi, Ghana, were screened by real-time PCR for enterovirus. Molecular typing of the VP1 region was performed. Enterovirus-positive samples were tested for norovirus, adenovirus, rotavirus, sapovirus, and cosaviruses. Twenty-six out of 250 HIV-positive subjects (10.4%) and 14 out of 102 HIV-negative individuals (13.7%) were detected enterovirus-positive, not showing a significant different infection rate between the two groups. HIV-negative individuals were infected with Enterovirus C strains only. HIV-positive participants were detected positive for species Enterovirus A, Enterovirus B, and Enterovirus C. Co-infections with other viral enteric pathogens were almost exclusively detected among HIV-positive participants. Overall, the present study provides the first data about enteroviruses within HIV-positive and HIV-negative adults living in Ghana.

Lower prevalence of Blastocystis sp. infections in HIV positive compared to HIV negative adults in Ghana

Background

Sub-Saharan Africa is endemic for intestinal parasites and distinguished for the largest burden of HIV cases. Blastocystis sp. is one of the most common protists infecting humans but its role in human disease is still controversial. Aim of this study was to investigate the prevalence of Blastocystis sp. in HIV positive and negative adults in Ghana and its association with immune status and other risk factors.

Methods

122 HIV positive outpatients and 70 HIV negative blood donors from the Komfo Anokye Teaching Hospital in Kumasi, Ghana, were included in the present study. Demographic, clinical and laboratory data were collected and HIV positive patients distinguished for CD4+ T cell count <200 cells/μl (n = 54) and >200 cells/μl (n = 68). A Blastocystis’s phylogenetic analysis was performed to determine sample subtype (ST).

Results

The prevalence of Blastocystis sp. in adult HIV positive individuals was lower than in HIV negative persons (6.6% vs. 20.0%, p = 0.008) and Blastocystis sp. ST1 was the most prevalent strain. Within HIV positive participants, the prevalence of Blastocystis sp. was lower in those individuals with CD4+ T cell count <200 cells/μl than in patients with higher CD4+ T cell count (1.9% vs. 10.3%, p = 0.076). Multiple regression analysis revealed that Blastocystis sp. was inversely associated with an obese Body Mass Index (BMI) in HIV negative persons (p = 0.040). Presence of Blastocystis sp. was correlated with higher CD4+ T cell count in HIV positive participants (p = 0.049).

Conclusion

It is largely reported that people living with HIV (PLHIV) in Africa are affected from parasite infections and that co-infections may adversely impact on their immune status, accelerating progress to AIDS and worsening gastrointestinal manifestations. Differently, in this study Blastocystis sp. was associated with a better immune status jointly with a healthy body weight while it seems to be reduced with the progression of HIV infection. This data agree with recent suggestions that Blastocystis sp. can represent a component of the healthy gut microbiota.

CD25+ FoxP3+ Memory CD4 T Cells Are Frequent Targets of HIV Infection In Vivo

Interleukin 2 (IL-2) signaling through the IL-2 receptor alpha chain (CD25) facilitates HIV replication in vitro and facilitates homeostatic proliferation of CD25(+) FoxP3(+) CD4(+) T cells. CD25(+) FoxP3(+) CD4(+) T cells may therefore constitute a suitable subset for HIV infection and plasma virion production. CD25(+) FoxP3(+) CD4(+) T cell frequencies, absolute numbers, and the expression of CCR5 and cell cycle marker Ki67 were studied in peripheral blood from HIV(+) and HIV(-) study volunteers. Different memory CD4(+) T cell subsets were then sorted for quantification of cell-associated HIV DNA and phylogenetic analyses of the highly variable EnvV1V3 region in comparison to plasma-derived virus sequences. In HIV(+) subjects, 51% (median) of CD25(+) FoxP3(+) CD4(+) T cells expressed the HIV coreceptor CCR5. Very high frequencies of Ki67(+) cells were detected in CD25(+) FoxP3(+) memory CD4(+) T cells (median, 27.6%) in comparison to CD25(-) FoxP3(-) memory CD4(+) T cells (median, 4.1%; P < 0.0001). HIV DNA content was 15-fold higher in CD25(+) FoxP3(+) memory CD4(+) T cells than in CD25(-) FoxP3(-) T cells (P = 0.003). EnvV1V3 sequences derived from CD25(+) FoxP3(+) memory CD4(+) T cells did not preferentially cluster with plasma-derived sequences. Quasi-identical cell-plasma sequence pairs were rare, and their proportion decreased with the estimated HIV infection duration. These data suggest that specific cellular characteristics of CD25(+) FoxP3(+) memory CD4(+) T cells might facilitate efficient HIV infection in vivo and passage of HIV DNA to cell progeny in the absence of active viral replication. The contribution of this cell population to plasma virion production remains unclear.

IMPORTANCE

Despite recent advances in the understanding of AIDS virus pathogenesis, which cell subsets support HIV infection and replication in vivo is incompletely understood. In vitro, the IL-2 signaling pathway and IL-2-dependent cell cycle induction are essential for HIV infection of stimulated T cells. CD25(+) FoxP3(+) memory CD4 T cells, often referred to as regulatory CD4 T cells, depend on IL-2 signaling for homeostatic proliferation in vivo Our results show that CD25(+) FoxP3(+) memory CD4(+) T cells often express the HIV coreceptor CCR5, are significantly more proliferative, and contain more HIV DNA than CD25(-) FoxP3(-) memory CD4 T cell subsets. The specific cellular characteristics of CD25(+) FoxP3(+) memory CD4(+) T cells probably facilitate efficient HIV infection in vivo and passage of HIV DNA to cell progeny in the absence of active viral replication. However, the contribution of this cell subset to plasma viremia remains unclear.

Helicobacter pylori Infection Is Associated with Higher CD4 T Cell Counts and Lower HIV-1 Viral Loads in ART-Naïve HIV-Positive Patients in Ghana

BACKGROUND

Worldwide, there is a high co-endemicity of HIV and H. pylori infection and there is growing evidence that H. pylori co-infection is associated with parameters of HIV disease progression. The objective of this study was to investigate the prevalence of H. pylori infection, and the association with clinical, immunological and virological parameters in a large cohort of HIV-infected individuals and uninfected controls in a West African country.

METHODS

HIV-patients (n = 1,095) and HIV-negative individuals (n = 107) were recruited at a university hospital in Ghana. H. pylori status was determined using stool antigen testing. HIV-related, clinical and socio-demographic parameters were recorded and analyzed according to H. pylori status.

RESULTS

The prevalence of H. pylori infection was significantly lower in HIV-positive compared to HIV-negative individuals (51.5 vs. 88%, p<0.0001). In HIV patients, H. pylori prevalence decreased in parallel with CD4+ T cell counts. In ART-naïve HIV-infected individuals, but not in those taking ART, H. pylori infection was associated with higher CD4 cell counts (312 vs. 189 cells/μL, p<0.0001) and lower HIV-1 viral loads (4.92 vs. 5.21 log10 copies/mL, p = 0.006). The findings could not be explained by socio-demographic confounders or reported use of antibiotics. Having no access to tap water and higher CD4+ T cell counts were identified as risk factors for H. pylori infection.

CONCLUSIONS

H. pylori prevalence was inversely correlated with the degree of immunosuppression. In ART-naïve individuals, H. pylori infection is associated with favorable immunological and virological parameters. The underlying mechanisms for this association are unclear and warrant investigation.