[Study of the immune system in relatives of children with dermatomyositis].

In view of the fact that relatives of patient with other connective tissue diseases may show immunologic abnormalities, we investigated cellular (PPD, SK-SD, candidine and diphteria-tetanous toxoid cutaneous tests) and humoral (IgG, IgM, IgA. CH50, C3, rheumatoid factor and ANA) immune responses in first degrees relatives (parents and siblings) of children with dermatomyositis. Of the 53 subjects tested, 19 had high values of one or two immunoglobulines; however, the mean Ig value was not different from that of the general population (p greater than 0.1), CH50, C3, rheumatoid factor and ANA were normal or negative. Cutaneous tests made on 46 subjects did not reveal abnormalities. Therefore our conclusion is that first degree relatives of children with dermatomyositis have not significant immunologic abnormalities.