Edmund Osei Kuffour

Background: Cryptosporidium spp. cause opportunistic infections in immunosuppressed individuals, such as people living with HIV (PLWH). However, the association between giardiasis and HIV infection remains uncertain. This study assessed co-infections in Ghanaian PLWH and HIV-negative individuals, analyzing socio-economic, clinical, and immunological implications, including the Giardia duodenalis assemblage and Cryptosporidium spp. sub-family levels. Methods: Stool samples from Ghanaian PLWH were tested using several real-time PCR assays targeting G. duodenalis at the species level and assemblages A and B to optimize diagnostic accuracy. GD60 gene-based Sanger sequencing was used for Cryptosporidium spp. subtyping. Results were correlated with anonymized patient data to evaluate interactions with HIV infection. Results: In PLWH, C. hominis Ib, C. hominis Ie, and C. parvum IIc were detected at similar frequencies, followed by C. hominis Ia, C. hominis Id, and C. parvum IIe in decreasing order. Only C. parvum IIc was repeatedly observed in individuals with CD4+ T cell counts above 200/µL, while other sub-families occurred preferentially in those with lower counts. C. hominis Ia and Ib were associated with PLWH not receiving antiretroviral therapy; C. hominis Ia was linked to recently diagnosed HIV infections. No relevant associations between G. duodenalis assemblages and HIV infection were found. Conclusions: Sub-families Ia and Ib of C. hominis preferentially occur in individuals with severe immunosuppression, while C. parvum IIc is also detectable in individuals with better immune function. The prevalence of giardiasis in Ghana appears to be influenced by factors other than HIV-induced immunosuppression.

Molecular diagnoses of Entamoeba histolytica and Strongyloides stercoralis in human samples are becoming increasingly common. To contribute to the ongoing standardization of molecular diagnostic approaches targeting these parasites, we compared three published E. histolytica- and S. stercoralis-specific real-time PCR assays in test comparisons without a reference standard. Latent class analysis (LCA) was used to calculate diagnostic accuracy estimations for the three compared assays per parameter. The comparison was conducted using stool samples from Ghanaian individuals. In the course of the assessment of 873 stool samples, the number of detected positive PCR results ranged from 10 to 15 for S. stercoralis and from 4 to 54 for E. histolytica depending on the applied assay. Diagnostic accuracy estimates of real-time PCR sensitivity for S. stercoralis and E. histolytica ranged from 89% to 100% and from 75% to 100%, respectively; diagnostic estimates of specificity ranged from 99% to 100% and from 94% to 100%, respectively. Diagnostic accuracy-adjusted prevalence estimates were 1.2% for S. stercoralis and 0.5% for E. histolytica. High cycle threshold values of real-time PCR > 35 showed a particularly reduced likeliness of reproducibility when applying competitor real-time PCR assays. There were no clear-cut differences in terms of diagnostic accuracy favoring either small-subunit ribosomal ribonucleic acid (SSU rRNA) gene sequences or the S. stercoralis dispersed repetitive sequence for S. stercoralis PCR. The same applied to the comparison of real-time PCRs targeting SSU rRNA gene sequences and the SSU rRNA episomal repeat sequence (SREPH) of E. histolytica. In conclusion, interchangeability of the compared real-time PCR assays was higher for the assessed S. stercoralis assays compared with the assessed E. histolytica assays. Regional diagnostic accuracy testing seems advisable before literature-adapted assays for rare tropical pathogens like S. stercoralis and E. histolytica are applied in different study regions.

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 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.

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.

There is a paucity of information on the prevalence, risk factors, and clinical correlates of people living with HIV (PLWH) who are co-infected with Cryptosporidium spp. in the post-combined antiretroviral therapy era in Ghana. To provide such data, in this observational study, stool samples of 640 HIV-positive and 83 HIV-negative individuals in Ghana were screened for Cryptosporidium spp. Additionally, sociodemographic parameters, clinical symptoms, medication intake, and immunological parameters were assessed. The prevalence of Cryptosporidium spp. was 11.8% (n = 73) in HIV-positive and 1.2% (n = 1) in HIV-negative participants (p < 0.001). Within the group of HIV-positive participants, the prevalence reached 26.0% in patients with CD4+ T cell counts below 200 cells/µL and 46.2% in the subgroup with CD4+ T cell counts below 50 cells/µL. The frequencies of the clinical manifestation of weight loss and gastrointestinal symptoms were significantly higher in patients with Cryptosporidium spp. compared to those without co-infection (45.8% vs. 21.4%, p < 0.001 and 22.2% vs. 12.2%, p = 0.031, respectively). In the modern post-cART era, the acquisition of Cryptosporidium spp. among PLWH in Ghana is driven largely by the degree of immunosuppression. Access to cART and screening for Cryptosporidium spp. as part of routine care might help control and reduce the burden of the infection.

The innate immune response to viruses is formed in part by interferon (IFN)-induced restriction factors, including ISG15, p21, and SAMHD1. IFN production can be blocked by the ISG15-specific protease USP18. HIV-1 has evolved to circumvent host immune surveillance. This mechanism might involve USP18. In our recent studies, we demonstrate that HIV-1 infection induces USP18, which dramatically enhances HIV-1 replication by abrogating the antiviral function of p21. USP18 downregulates p21 by accumulating misfolded dominant negative p53, which inactivates wild-type p53 transactivation, leading to the upregulation of key enzymes involved in de novo dNTP biosynthesis pathways and inactivated SAMHD1. Despite the USP18-mediated increase in HIV-1 DNA in infected cells, it is intriguing to note that the cGAS-STING-mediated sensing of the viral DNA is abrogated. Indeed, the expression of USP18 or knockout of ISG15 inhibits the sensing of HIV-1. We demonstrate that STING is ISGylated at residues K224, K236, K289, K347, K338, and K370. The inhibition of STING K289-linked ISGylation suppresses its oligomerization and IFN induction. We propose that human USP18 is a novel factor that potentially contributes in multiple ways to HIV-1 replication.

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.

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.