An Expression Quantitative Trait Locus of Fc Gamma Receptor Genes is Associated with Anti-Malarial IgG Responses and Infection Levels in Burkinabe Families.

BACKGROUND: The interaction between antibodies and Fc gamma receptors (FcγRs) plays a critical role in regulating immune responses to Plasmodium falciparum. Polymorphisms in genes encoding FcγRs influence the host's capacity to control parasite infection. This study investigates whether non-coding variants influencing FcγR expression are associated with anti-malarial immunization and infection traits. METHODS: We utilized eQTL databases and functional annotations to identify non-coding variants, specifically rs1771575, rs2099684, and rs6700241, within the FCGR gene cluster. In addition, we examined the coding variants rs1801274 (p.His167Arg) and rs1050501 (p.Ile231Thr), which affect the affinity of FcγRIIa and FcγRIIb for IgG. These variants were genotyped in 163 individuals from Burkinabe families. Family-based linear mixed regression and Quantitative Transmission Disequilibrium Tests (QTDT) analyses were performed to assess associations with IgG levels and malaria infection, accounting for relevant covariates. RESULTS: Linear mixed models identified rs1771575 as associated with total IgG levels, while both rs1771575 and rs1801274 were linked to IgG2, and rs1050501 to IgG1 levels. A haplotype combining rs2099684 and rs6700241 was positively associated with IgG1. The rs1771575-CC and rs1050501-TT genotypes correlated with higher infection levels in children. QTDT models confirmed the association of rs1771575 with IgG2 and infection in children. CONCLUSIONS: Our findings suggest that the intergenic variant rs1771575 serves as an independent marker for IgG levels and blood infection in children. This highlights the interplay between regulatory variants and coding mutations in FCGR, which may influence immune function and antibody production. These results underscore the potential for personalized strategies to monitor humoral responses in malaria-endemic regions.

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.

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.