TNF-α production in whole blood cultures upon stimulation with LPS was determined in 179 individuals from 61 families in order to characterise the magnitude of inherited differences in TNF-α production. The three families characterised by highest TNF production showed 7.1 ± 0.3 ng TNF/ml upon culture with 10 ng LPS and 10.2 ± 0.2 ng TNF/ml upon culture with 1000 ng LPS, in contrast to the three families characterised by the lowest TNF production that showed a production of 1.6 ± 0.1 ng TNF upon culture with 10 ng and 2.5 ± 0.2 ng/ml upon culture with 1000 ng LPS/ml. This difference could not be attributed to the promoter polymorphisms -308 G to A, -238 G to A or -376 G to A, although the -238 GA donors produced 2.1 ± 0.9 ng TNF upon culture with 10 ng endotoxin compared to 3.2 ± 2.2 ng TNF for the -238 GG donors. In line with these results the frequency of the -238 GG genotype was increased in hospitalized MS patients in a nursing home (100% 238GG, n = 57) compared to MS patients in an outpatient's clinic (94% 238GG, n = 98) or Dutch controls (90% 238GG, n = 180). These results suggest that the -238 GG genotype is differently distributed in hospitalized MS patients in a nursing home.