Allelic combinations of immune-response genes as possible composite markers of IFN-ß efficacy in multiple sclerosis patients.

BACKGROUND: IFN-ß is widely used as the first-line disease-modifying treatment for multiple sclerosis. However, 30-50% of multiple sclerosis patients do not respond to this therapy. Identification of genetic variants and their combinations that predict responsiveness to IFN-ß could be useful for treatment prognosis. MATERIALS & METHODS: The combinations of alleles of nine polymorphic loci in immune-response genes were analyzed in 253 Russian multiple sclerosis patients as possible determinants of clinically optimal IFN-ß treatment response using APSampler software. RESULTS: Carriage of TGFB1*-509C and CCR5*d was associated with favorable IFN-ß response by itself. CCR5*d, IFNAR1*16725G, IFNG*874T and IFNB1*153T/T were the components of the combinations, associated with clinically optimal response to IFN-ß. Carriage of composite markers (CCR5*d + IFNAR1*G + IFNB1*T/T) or (CCR5*d + IFNAR1*G + IFNG*T) is beneficial for IFN-ß treatment efficacy. DISCUSSION: The data obtained provides evidence of the cumulative effect of immune-response genes on IFN-ß treatment efficacy. This joint contribution may reflect the additive effect of independent allelic variants and epistatic interactions between some of them.

Allelic combinations of immune-response genes associated with glatiramer acetate treatment response in Russian multiple sclerosis patients.

BACKGROUND: Glatiramer acetate (GA) is widely used as a first-line disease-modifying treatment for multiple sclerosis (MS). However, a significant proportion of MS patient appears to experience modest benefit from GA-treatment. Genetic variants affecting the clinical response to GA are believed to be relevant as biomarkers of GA-treatment efficiency. PATIENTS & METHODS: Nine polymorphisms in candidate genes were analyzed as possible determinants of GA response in 285 Russian MS patients. Special attention was given to identification of response-associated allelic combinations by means of the APSampler algorithm. RESULTS: No significant associations were found for individual polymorphisms. Alleles DRB1*15, TGFB1*T, CCR5*d and IFNAR1*G were the components of the combinations, of which carriage was significantly higher in nonresponders than in responders. Carriers of the most significant combinations: DRB1*15 + TGFB1*T + CCR5*d + IFNAR1*G and DRB1*15 + TGFB1*T + CCR5*d (permutation p-values: 0.0056 and 0.013, respectively) had a 14 to 15-times increased risk of ineffective response to GA therapy. DISCUSSION: The results suggest that the influence of immune-response genes on GA-induced response has a polygenic nature. The data are interpreted as evidence of additive and epistatic influences of the genes on GA efficiency for MS treatment.