Occurence and clinical relevance of an interleukin-4 gene polymorphism im patients with multiple sclerosis

An epistatic gene interaccion has been advocated to explain disease susceptibility in Multiple Sclerosis (MS). Cytokine genes are possible candidate due to the central role played by cytokines in the regulation of the immuno-mediated pathogenetic processes leading to the central nervous system demyelination in these patients. Since interleukin (ID -4 gene polymorphisms have been associated with immune-mediated diseases, we have analysed the relationship between a variable number of tandem repeats (VNTR) polymorphisms of the IL-4 gene and clinical and physiological features of 256 sporadic MS patients and 1.15 healthy controls. Genotype frequencies were similar between MS group and healthy controls. However, in MS patients a positive and significant correlation (r=0.91; p<0.001) was found between the carriage rate of the IL-4 Bl allele (from 0.21 to 0.36) and the age of disease onset. No association was found between IL-4 alleles and disease progression, sex or ethnic background of the patients. Our results show that IL-4 Bl allele is associated with late onset of MS and therefore might represent a modifier of age of onset rather than a susceptibility factor for patients with MS.