Background To assess the genetic influence on cytokine production and
its contribution to fatal outcome, we determined the capacity to produ
ce tumour necrosis factor-alpha (TNF alpha) and interleukin-10 (IL-10)
in families of patients who had had meningococcal disease. Methods We
studied 190 first-degree relatives of 61 patients with meningococcal
disease; we also studied 26 monozygotic twins. Production of cytokines
was determined during endotoxin stimulation of whole-blood samples ex
-vivo. Heritability was estimated in a pedigree-based maximum-likeliho
od model. DNA was typed for the G to A transition polymorphisms at pos
ition -308 and -238 in the TNF gene promoter. Findings Heritability in
monozygotic twins was 0 . 60 for the production of TNF and 0 . 75 for
the production of IL-10, Families with low TNF production had a tenfo
ld increased risk for fatal outcome (OR 8 . 9, 95% Cl 1 . 8-45), where
as high IL-10 production increased the risk 20-fold (19 . 5, 2 . 3-165
). Families with both characteristics had the greatest risk. The trans
ition polymorphisms in the TNF gene promoter were not associated with
outcome. Interpretation Genetic factors substantially influence produc
tion of cytokines. An innate anti-inflammatory cytokine profile may co
ntribute to fatal meningococcal disease.