A Non-Coding Fc Gamma Receptor Cis-Regulatory Variant within the 1q23 Gene Cluster Is Associated with Plasmodium falciparum Infection in Children Residing in Burkina Faso.

Antibodies play a crucial role in activating protective immunity against malaria by interacting with Fc-gamma receptors (FcγRs). Genetic variations in genes encoding FcγRs can affect immune cell responses to the parasite. In this study, our aim was to investigate whether non-coding variants that regulate FcγR expression could influence the prevalence of Plasmodium falciparum infection. Through bioinformatics approaches, we selected expression quantitative trait loci (eQTL) for FCGR2A, FCGR2B, FCGR2C, FCGR3A, and FCGR3B genes encoding FcγRs (FCGR), in whole blood. We prioritized two regulatory variants, rs2099684 and rs1771575, located in open genomic regions. These variants were identified using RegVar, ImmuNexUT, and transcription factor annotations specific to immune cells. In addition to these, we genotyped the coding variants FCGR2A/rs1801274 and FCGR2B/rs1050501 in 234 individuals from a malaria-endemic area in Burkina Faso. We conducted age and family-based analyses to evaluate associations with the prevalence of malarial infection in both children and adults. The analysis revealed that the regulatory rs1771575-CC genotype was predicted to influence FCGR2B/FCGR2C/FCGR3A transcripts in immune cells and was the sole variant associated with a higher prevalence of malarial infection in children. In conclusion, this study identifies the rs1771575 cis-regulatory variant affecting several FcγRs in myeloid and neutrophil cells and associates it with the inter-individual capacity of children living in Burkina Faso to control malarial infection.

Safety of Chloroquine or Hydroxychloroquine Plus Azithromycin for the Treatment of COVID-19 Patients in Burkina Faso: An Observational Prospective Cohort Study.

INTRODUCTION: Though chloroquine derivatives are used in the treatment of coronavirus disease 2019 (COVID-19) in many countries worldwide, doubts remain about the safety and efficacy of these drugs, especially in African communities where published data are scarce. METHODS: We conducted an observational prospective cohort study from April 24 to September 03, 2020, in Burkina Faso to assess (as primary outcome) the clinical, biological, and cardiac (electrocardiographic) safety of chloroquine or hydroxychloroquine plus azithromycin administered to COVID-19 patients. The main secondary outcomes were all-cause mortality and median time of viral clearance. RESULTS: A total of 153 patients were enrolled and followed for 21 days. Among patients who took at least one dose of chloroquine or hydroxychloroquine (90.1% [138/153]), few clinical adverse events were reported and were mainly rash/pruritus, diarrhea, chest pain, and palpitations. No statistically significant increase in hepatic, renal, and hematological parameters or electrolyte disorders were reported. However, there was a significant increase in the QTc value without exceeding 500ms, especially in those who received chloroquine phosphate. Three adverse events of special interest classified as serious (known from chloroquine derivatives) were recorded namely pruritus, paresthesia, and drowsiness. One case of death occurred. The average onset of SARS-CoV-2 PCR negativity was estimated at 7.0 (95% CI: 5.0-10.0) days. CONCLUSION: Hydroxychloroquine appeared to be well tolerated in treated COVID-19 patients in Burkina Faso. In the absence of a robust methodological approach that could generate a high level of scientific evidence, our results could at least contribute to guide health decisions that should be made based on different sources of scientific evidence including those from our study.

A genome scan for Plasmodium falciparum malaria identifies quantitative trait loci on chromosomes 5q31, 6p21.3, 17p12, and 19p13.

BACKGROUND: Genome-wide studies have mapped several loci controlling Plasmodium falciparum mild malaria and parasitaemia, only two of them being significant at the genome level. The objective of the present study was to identify malaria resistance loci in individuals living in Burkina Faso. METHODS: A genome scan that involved 314 individuals belonging to 63 families was performed. Markers located within chromosomes 6p21.3 and 17p12 were genotyped in 247 additional individuals belonging to 55 families. The linkage and the association of markers with parasitaemia and mild malaria were assessed by using the maximum-likelihood binomial method extended to quantitative trait linkage and the quantitative trait disequilibrium test, respectively. RESULTS: Multipoint linkage analysis showed a significant linkage of mild malaria to chromosome 6p21.3 (LOD score 3.73, P = 1.7 10-5), a suggestive linkage of mild malaria to chromosome 19p13.12 (LOD score 2.50, P = 3.5 10-4), and a suggestive linkage of asymptomatic parasitaemia to chromosomes 6p21.3 (LOD score 2.36, P = 4.9 10-4) and 17p12 (LOD score 2.87, P = 1.4 10-4). Genome-wide family-based association analysis revealed a significant association between three chromosome 5q31 markers and asymptomatic parasitaemia, whereas there was no association with mild malaria. When taking into account 247 additional individuals, a significant linkage of asymptomatic parasitaemia to chromosome 17p12 (LOD score 3.6, P = 2 10-5) was detected. CONCLUSION: A new genome-wide significant malaria locus on chromosome 17p12 and a new suggestive locus on chromosome 19p13.12 are reported. Moreover, there was evidence that confirmed the influence of chromosomes 5q31 and 6p21.3 as loci controlling mild malaria or asymptomatic parasitaemia.

Rheumatoid arthritis in Burkina Faso: clinical and serological profiles.

The objective of this work was to study the clinical and serological profiles of rheumatoid arthritis in Burkina Faso (West Africa). It is a cross-sectional study conducted from March 2006 to February 2009 in the Internal Medicine Department of the University Hospital Yalgado Ouedraogo. All patients seen in the rheumatologic consultation unit during this period, with rheumatoid arthritis fulfilling the ACR criteria, were routinely selected. The determination of anticyclic citrullinated peptide antibodies (ACPA) was carried out with a computerized method (Elia CCP, Phadia AB, Uppsala, Sweden). Values higher than 10 IU/l were considered positive. Forty-eight cases of rheumatoid arthritis (RA) were recruited throughout the study period among 2,194 (2.2 %) patients. Forty-two files were subjected to the study. There were 34 women and 8 men. The average age was 41.70 ± 13 years with extremes of 22 and 71 years. The average duration of the disease was 86.17 ± 82.01 months with extremes of 8 and 360 months. Rheumatoid factors (RF) were positive in 21 out of 30 patients (70.0%). The determination of ACPA carried out in all the patients was positive in 34 (81%) patients; their average value was 217 IU/l with extremes of 38 and 1,170. RF and ACPA were associated to bones erosions (p = 0.0001). Twenty-two patients were placed on methotrexate, eight on hydroxychloroquine, and three on salazopyrine. Nine were given only NSAIDs or prednisolone. No patients had had a biotherapy agent. The frequency of RA was low in our study compared to other African studies published so far. The particularity of RA cases reported in African series, including ours, is the rarity of extra-articular manifestations of the disease. The severity of the disease at presentation in the rheumatology clinic may be due to their late consultation among other causes.

Natural killer cell and macrophage cooperation in MyD88-dependent innate responses to Plasmodium falciparum.

IFN-gamma secretion by natural killer (NK) cells is pivotal to several tumor and viral immune responses, during which NK and dendritic cells cooperation is required. We show here that macrophages are mandatory for NK cell IFN-gamma secretion in response to erythrocytes infected with Plasmodium falciparum (Pf), a causative agent of human malaria. In addition, direct sensing of Pf infection by NK cells induces their production of the proinflammatory chemokine CXCL8, without triggering their granule-mediated cytolytic programs. Despite their reported role in Pf recognition, Toll-like receptor (TLR) 2, TLR9, and TLR11 are individually dispensable for NK cell activation induced by Pf-infected erythrocytes. However, IL-18R expression on NK cells, IL-18 production by macrophages, and MyD88 on both cell types are essential components of this previously undescribed pathway of NK cell activation in response to a parasite infection.

Linkage of mild malaria to the major histocompatibility complex in families living in Burkina Faso.

Tumor necrosis factor alpha (TNF alpha) is thought to be a critical mediator of malaria fever, and mild malaria was previously reported to be linked to the MHC region containing the tumor necrosis factor alpha gene (TNF). Thirty-four families from Burkina Faso were analyzed to test for linkage between polymorphisms within the MHC region and mild malaria using the maximum-likelihood-binomial (MLB) program. Two-point analysis indicated linkage of mild malaria to TNFd (LOD = 3.27; P = 5.44 x 10(-5)). Using multipoint analysis, we also found evidence for linkage of mild malaria to the MHC region, with a peak close to TNF (LOD = 3.86; P = 1.22 x 10(-5)). Our results support genes within the MHC region being involved in mild malaria. In particular, the genetic variation within TNF may influence susceptibility to mild malaria. Nevertheless, TNF-238, TNF-244 and TNF-308 polymorphisms are unlikely to explain linkage of mild malaria to the MHC region, and the causal mutations remain to be identified.