title: Fc gamma RIIa (CD32) polymorphism and onchocercal skin disease: implications for the development of severe reactive onchodermatitis (ROD).
abstract: The pathologic manifestations of Onchocerca volvulus infection depend on the interplay between the host and the parasite. A genetic single nucleotide polymorphism in the Fc gamma RIIa gene, resulting in arginine (R) or histidine (H) at position 131, affects the binding to the different IgG subclasses and may influence the clinical variations seen in onchocerciasis. This study investigated the relationship between this polymorphism and disease outcome. Fc gamma RIIa genotyping was performed on clinically characterized onchocerciasis patients (N = 100) and healthy controls (N = 74). Fc gamma RIIa genotype R/R131 frequencies were significantly higher among patients with severe dermatopathology (P < 0.001). Increased risk of developing this form was mostly associated with one tribe (Masalit) (OR = 3.2, 95% CI 1-9.9, P = 0.042). The H131 allele was found to be significantly associated with a reduced risk of having the severe form of the disease (adjusted OR = 0.26, 95% CI = 0.13-0.46, P < 0.001). Our findings suggest that the polymorphism influences the clinical outcome of onchocerciasis.
authors.affiliation: Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan.
authors.forename: Magdi M M
authors.initials: MM
authors.lastname: Ali
authors.forename: Gehad
authors.initials: G
authors.lastname: Elghazali
authors.forename: Scott M
authors.initials: SM
authors.lastname: Montgomery
authors.forename: Salah E
authors.initials: SE
authors.lastname: Farouk
authors.forename: Amre
authors.initials: A
authors.lastname: Nasr
authors.forename: Suzan I A
authors.initials: SI
authors.lastname: Noori
authors.forename: Mahdi M
authors.initials: MM
authors.lastname: Shamad
authors.forename: Omar E
authors.initials: OE
authors.lastname: Fadlelseed
authors.forename: Klavs
authors.initials: K
authors.lastname: Berzins
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D015703:Antigens, CD / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D017181:Onchocerca volvulus / Q000472:pathogenicity*; D009855:Onchocerciasis / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D017452:Receptors, IgG / Q000235:genetics*; D012307:Risk Factors; D012720:Severity of Illness Index; D013397:Sudan / Q000453:epidemiology
chemical_list: D015703:Antigens, CD; D017931:DNA Primers; C080568:Fc gamma receptor IIA; D017452:Receptors, IgG