Association between immunoglobulin GM and KM genotypes and placental malaria in HIV-1 negative and positive women in western Kenya

Combined polymorphisms involving the IgG heavy chain and fc gamma receptors among Fulani and non-Fulani in Benin: Implications for the natural protection of young Fulani against plasmodium. Falciparum malaria infections

A decreased susceptibility of Fulani populations to malaria infections has been shown in Africa. A previous longitudinal cohort study conducted in the Atacora region of northern Benin showed a high merozoite-phagocytosis capacity in young Fulani. Here, we explored the combined polymorphisms in the constant region of the IgG3 heavy chain (presence/absence of the G3m6 allotype) and in Fc gamma receptors (FcγRs) as potentially involved in the natural protection against malaria of young Fulani in Benin. An active malaria follow-up was conducted among individuals from Fulani, Bariba, Otamari and Gando ethnic groups living in sympatry in Atacora, over the full malaria transmission season. FcγRIIA 131R/H (rs1801274), FcγRIIC C/T (rs3933769) and FcγRIIIA 176F/V (rs396991) were determined using the TaqMan method; FcγRIIIB NA1/NA2 was assessed by polymerase chain reaction (PCR) using allele-specific primers and G3m6 using allotype by PCR-RFLP. Individual carriage of G3m6 (+) was associated with an increased risk of Pf malaria infection (logistic multivariate regression model (lmrm), IRR = 2.25, 95% CI = 1.06;4.74, P = 0.034). Combined haplotype G3m6 (+) - FcγRIIA 131H - FcγRIIC T - FcγRIIIA 176F - FcγRIIIB NA2 was also associated with an increased risk of Pf malaria infection (lmrm, IRR = 13.01, 95% CI = 1.69;99.76, P = 0.014). G3m6 (-), FcγRIIA 131R and FcγRIIIB NA1 were more prevalent in young Fulani (P = 0.002, P < 0.001 and P = 0.049, respectively), while no Fulani presented the combined G3m6 (+) - FcγRIIA 131H - FcγRIIC T - FcγRIIIA 176F - FcγRIIIB NA2 haplotype that was carried by a majority of infected children. Our results highlight the combined factors G3m6 - FcγR as potentially involved in the merozoite-phagocytosis capacity and in the natural protection of young Fulani individuals against P. falciparum malaria in Benin.

Malaria prevalence in HIV-positive children, pregnant women, and adults: a systematic review and meta-analysis

Background

Malaria in human immunodeficiency virus (HIV)-positive patients is an ever-increasing global burden for human health. The present meta-analysis summarizes published literature on the prevalence of malaria infection in HIV-positive children, pregnant women and adults.

Methods

This study followed the PRISMA guideline. The PubMed, Science Direct, Google Scholar, Scopus and Cochrane databases were searched for relevant entries published between 1 January 1983 and 1 March 2020. All peer-reviewed original papers evaluating the prevalence of malaria among HIV-positive patients were included. Incoherence and heterogeneity between studies were quantified by the I2 index and Cochran’s Q test. Publication and population biases were assessed with funnel plots, and Egger’s regression asymmetry test.

Results

A total of 106 studies were included in this systematic review. The average prevalence of malaria among HIV-positive children, HIV-positive pregnant women and HIV-positive adults was 39.4% (95% confidence interval [CI]: 26.6–52.9), 32.3% (95% CI = 26.3–38.6) and 27.3% (95% CI = 20.1–35.1), respectively. In adult patients with HIV, CD4+ (cluster of differentiation 4) < 200 cells/µl and age < 40 years were associated with a significant increase in the odds of malaria infection (odds ratio [OR] = 1.5, 95% CI = 1.2–1.7 and OR = 1.1, 95% CI = 1–1.3, respectively). Antiretroviral therapy (ART) and being male were associated with a significant decrease in the chance of malaria infection in HIV-positive adults (OR = 0.8, 95% CI = 0.7–0.9 and OR = 0.2, 95% CI = 0.2–0.3, respectively). In pregnant women with HIV, CD4+ count < 200 cells/µl was related to a higher risk for malaria infection (OR = 1.5, 95% CI = 1.1–1.9).

Conclusions

This systematic review demonstrates that malaria infection is concerningly common among HIV-positive children, pregnant women and adults. Among HIV-positive adults, ART medication and being male were associated with a substantial decrease in infection with malaria. For pregnant women, CD4+ count of < 200 cells/µl was a considerable risk factor for malaria infection.

Graphical Abstract

Role of IgG3 in Infectious Diseases

IgG3 comprises only a minor fraction of IgG and has remained relatively understudied until recent years. Key physiochemical characteristics of IgG3 include an elongated hinge region, greater molecular flexibility, extensive polymorphisms, and additional glycosylation sites not present on other IgG subclasses. These characteristics make IgG3 a uniquely potent immunoglobulin, with the potential for triggering effector functions including complement activation, antibody (Ab)-mediated phagocytosis, or Ab-mediated cellular cytotoxicity (ADCC). Recent studies underscore the importance of IgG3 effector functions against a range of pathogens and have provided approaches to overcome IgG3-associated limitations, such as allotype-dependent short Ab half-life, and excessive proinflammatory activation. Understanding the molecular and functional properties of IgG3 may facilitate the development of improved Ab-based immunotherapies and vaccines against infectious diseases.

The Effect of Malaria and HIV Co-Infection on Anemia: A Meta-Analysis

Malaria and human immunodeficiency virus (HIV) infections are globally important public health concerns. The objectives of this study were (i) to determine the prevalence of malaria and HIV co-infections in people living in endemic countries, and (ii) to assess the effect of co-infection on anemia.Studies were searched on electronic databases including PubMed, Embase, Medline, Google Scholar, and African Journals Online. Observational studies, assessing the prevalence of co-infection and reporting its association with anemia, were included. The methodological quality of included studies was assessed using a tool called the risk of bias assessment for non-randomized studies. Heterogeneity among studies was investigated with the I-square test. Pooled prevalence of the co-infection and its 95% confidence interval (CI) were estimated using the random-effect model, reflected on heterogeneity among studies. Summary odds ratio (OR), summary standardized mean difference (SMD), and their corresponding 95% CIs were estimated, as appropriate. Subgroup analysis and meta-regression were performed for robustness of results. Publication bias was assessed by visualization of a funnel plot.Twenty-three studies were included in the present study. Overall, the pooled prevalence of co-infection was 19% (95% CI: 15-23%, I: 98.1%), showing 26% (95% CI: 20-32%, I: 98.7%) in adults, 12% (95% CI: 7-17%, I: 95.0) in pregnant women, and 9% (95% CI: 6-11%, I: 68.6%) in children. Anemia was comparable between the monoinfected and co-infected adults (summary OR: 1.49, 95% CI: 0.93-2.37) and increased by 49% in co-infected pregnant women (summary OR: 1.49, 95% CI: 1.14-1.94). The mean hemoglobin concentration was significantly lower in the co-infected group than the monoinfected group (summary SMD: -0.47, 95% CI: -0.61 to -0.33). The results of meta-regression on the prevalence of co-infection using the publication year and total population as covariates showed the I value remained high implying a de facto random distribution of heterogeneity. An asymmetrical funnel plot indicated the presence of publication bias. Due to heterogeneity of the studies in this review, the results have to be interpreted with caution.The findings of this study suggest that the prevalence of malaria and HIV co-infection, particularly in pregnant women, requires special attention from healthcare personnel. Better understanding of the co-infection is crucial for designing treatment strategies. Future well-powered, prospective designs assessing the interaction between malaria and HIV are recommended.