[Incidence and diagnostic significance of reactive syphilis antibodies in systemic lupus erythematodes and other immunologic diseases].

Serum samples of 78 patients with systemic lupus erythematosus, systemic sclerosis and other immunological diseases were tested for antibodies to syphilis. Reactive or weak reactive results were observed in 10% by means of the treponema pallidum hemagglutination (TPHA) test, in 27% by the FTA-Abs test, in 40% applying the IgM-FTA-Abs test, in 10% by the VDRL test and in 3% of the cases using the cardiolipin CF test. Only in 3 patients (4%) we found an antibody pattern characteristic of syphilitic patients (TPHA and FTA-Abs test simultaneously undoubtedly reactive). Neither the comparative qualitative and quantitative determination of antibodies to ANA, nDNS and ENA (extractable salinesoluble nuclear antigen) nor elimination of nDNS and ENA antibodies, or incubation of the treponemal test antigen with DNase lead to a conclusion whether the reactive results of the TPHA, FTA-Abs, and IgM-FTA-Abs tests specifically indicate a syphilitic infection. The low incidence of reactive syphilis tests in SLE and the presence of syphilitic antibodies in other immunological diseases limitate the significance for the criterium in the diagnosis of SLE.