A three base pair gene variation within the distal 5'-flanking region of the interleukin-10 (IL-10) gene is related to the in vitro IL-10 production capacity of lipopolysaccharide-stimulated peripheral blood mononuclear cells.

Interleukin-10 (IL-10) is an important multifunctional immunmodulator. There is evidence that IL-10 secretion is associated with certain genetic elements of the proximal IL-10 gene 5'-flanking region. The allelic and genotypic comparison of IL-10 expression by lipopolysaccharide (LPS)- stimulated leukocytes (PBMC) with a recently discovered distal "indel" DNA-sequence variation at - 7400 bp revealed significant inter-individual differences in the IL-10 in vitro production capacity. Homozygotes lacking the three base pairs "GGA" (- 7400del) at this gene locus are characterised by high expression of IL-10 with a median of 1690pg/ml (P <or=0.009). The allelic comparison supports this finding (P <or=0.002). Further analysis of the haplotype -7400/- 1087 showed that homozygotes for - 7400del/- 1087G may be classified as very strong IL-10 responders with a median IL-10 secretion of 2378 pg/ml (P