ABSTRACT
While the basic cause of autoimmune diseases remains elusive, there is now greater understanding of their pathogenesis. Genetic influences are increasingly evident, the HLA complex being the best known predisposing factor [5]. However, there are non genetic risk factors, as concordance for disease in identical twins can be as low as 15% in the case of rheumatoid arthritis. [6]. Of the genetic influences, there is increasing evidence that some may involve cytokines. For example, there are genetically associated differences in TNF production [7,8], and polymorphisms in the promoters of TNFα and IL-1 receptor antagonist have been associated with predisposition to, or severity of various autoimmune diseases [9,10].
