[HLA-B27 in the families of probands with arthritis after acute respiratory tract disease].

HLA B27 antigen was found in 10/25 patients with arthritis after acute respiratory disease (ARD) and in 21/75 direct relatives of 23 of these probands, where a genealogical investigation could be made. With regard to the 9.5% incidence of HLA B27 in the Czech population this implies a positive association in patients (RR = 6.35) and direct relatives (R = 3.70). In the sub-group of HLA B27 positive probands HLA B27 positivity was found in 19/27 (70.4%) of direct relatives (RR = 22.6). In one female relative a recurrent monoarthritis of the talo-crural joint was found, the remainder did not suffer from inflammatory changes of the joints. The revealed positive associations indicate the probability of arthritis after ARD in HLA B27 positive subjects and their families. They indicate also that in arthritis after ARD reactive arthritis is involved with a less common organ manifestation of the initial infection.