Differences in the genotypes and plasma concentrations of the interleukin-1 receptor antagonist in black and white South African asthmatics and control subjects

The allelic frequency of a variable tandem repeat (VNTR) polymorphism in in tron 2 of the IL-1 Ra gene was studied in black and white patients with ast hma as well as control individuals. The plasma IL-1 Ra concentration was al so determined in asthmatics and compared to control individuals. The 410-bp allele of the IL-1 Ra was significantly increased in all black subjects (9 0%) as compared to all white subjects (74%, P<0.0001), while the 240-bp all ele was significantly reduced in all black subjects (11%) as compared to al l white subjects (27%, P<0.0001). There was no difference in the frequency of the VNTR of the IL-1 Ra between black asthmatics and black controls and between white asthmatics and white controls. The IL-1 Ra levels were signif icantly increased in black and white patients with severe or moderate asthm a as compared to patients with mild asthma, Increased plasma concentrations of the IL-1 Ra was found to be associated with disease severity in all ast hmatic patients. (C) 2000 Academic Press.