A rare non-synonymous c.102C>\>G SNP in the IFNB1 gene might be a risk factor for cerebral malaria in Indian populations

Abstract

Interferon beta1 (IFNB1) is a type I interferon that is mainly known for its antiviral activity, but it also regulates a number of anti-inflammatory and immunomodulatory functions. Studies on mouse models of cerebral malaria have established that IFNB1 regulates severe malaria pathogenesis and increases overall survival against malaria. It down-regulates pro-inflammatory cytokines: TNF, IFNG and ICAM-1, resulting in decreased adherence of Plasmodium falciparum parasitized RBC to capillary wall, entry into the brain and delayed onset of death. Therefore, we hypothesized that variations in IFNB1 gene could regulate malarial pathogenesis. We re-sequenced the complete IFNB1 gene along with 900 bp of 5′ up-stream and 500 bp of 3′-UTR in 437 individuals from malaria endemic regions of the Orissa and Chhattisgarh states of India. The subjects comprised of 173 cases of severe malaria, 101 of mild malaria, and 156 ethnically matched asymptomatic controls. Data were statistically compared between cases and controls for their possible association with P. falciparum malarial outcome. Two Single Nucleotide Polymorphisms (SNPs): a synonymous c.153C>T (rs1051922) and a non-synonymous substitution c.102C>G (rs139262191, p.Ser34Arg) were identified. The genotype and allele distribution of c.153C>T did not differ significantly between the study groups [mild, χ²₂ = 4.10, p-value < 0.13 and severe χ²₂ = 0.06, p-value < 0.97]. Interestingly, the rare non-synonymous SNP (rs139262191) was observed only in malaria patients. The differences between all cases and controls did not reach statistical significance, however, a statistically significant difference was observed between the asymptomatic control group and the cerebral malaria group [OR = 20.32, 95% CI = 1.08–382.63, p-value = 0.044]. Moreover, the genotypes between cerebral malaria positive and negative groups were not significantly different [OR = 5.58, 95% CI = 0.61–50.97, p-value = 0.123]. Our findings suggest that the IFNB1 variant, p.Ser34Arg, might be a risk factor for cerebral malaria in Indian populations.