OCCURRENCE AND CLINICAL RELEVANCE OF AN INTERLEUKIN-4 GENE POLYMORPHISM IN PATIENTS WITH MULTIPLE-SCLEROSIS

An epistatic gene interaction has been advocated to explain disease su sceptibility in multiple sclerosis (MS). Cytokine genes are possible c andidates due to the central role played by cytokines in the regulatio n of the immune-mediated pathogenetic process leading to central nervo us system demyelination in these patients, Since interleukin (IL)-4 ge ne polymorphisms have been associated with immune-mediated diseases, w e have analysed the relationship between a variable number of tandem r epeat polymorphism of the IL-4 gene and clinical and physiological fea tures of 256 sporadic MS patients and 146 healthy controls. Genotype f requencies were similar between the MS group and healthy controls. How ever, in MS patients a positive and significant correlation (r = 0.91; p < 0.001) was found between the carriage rate of the IL-4 B1 allele (from 0.21 to 0.36) and age of disease onset. No association was found between IL-4 alleles and disease progression, sex or ethnic backgroun d of the patients. Our results show that the IL-4 B1 allele is associa ted with late onset of MS and therefore might represent a modifier of age of onset rather than a susceptibility factor for patients with MS.