[Immunoblotting for the serodiagnosis of syphilis. A candidate to replace the Nelson-Mayer test]

The lipid antigens used in the Bordet-Wassermann and prepared by Landsteiner and Marie for syphilis tests from 1909 to 1949 were non specific but have certain common features with the spirochete body. For more than forty years the Bordet-Wassermann reaction, associated with flocculation (Kahn) or agglutination (Kline-VDRL) was used to detect cases of tremonematosis despite frequent false positives reactions due to other infections. In 1949, the Nelson and Mayer test was introduced. This test was based on a rigorously specific reaction based on an antigen of live virulent Treponema pallidum. Culture being impossible, the strain had to be, and still is, maintained by weekly passage on rabbit testicles. These manipulations are very dangerous and the technique is difficult, being performed only in specialized laboratories. This test however made it possible to identify the specificity of lipid tests and led to the development of specific immunofluorescent reactions (FTA) in 1959 and of hemagglutination test (TPHA) in 1969. In 1980, we introduced a simple treponemic reaction (FTA or TPHA) associated with a lipid reaction (VDRL) for screening. The specificity of these tests is not however perfect and the Nelson test remains useful as a highly specific reaction. A simple test with comparable specificity was long awaited and is now available with immunoblotting as for HIV, boreliosis and pertussis, etc. We propose this new reaction to replace the Nelson test because it is specific, is sensitive early, distinguishes between IgG and IgM and is not dangerous to manipulate. We have tested it in over one hundred selected sera of CSF from subjects with recent, former or nervous syphilis as well as cases susceptible of producing false positive reactions and have concluded that immunoblotting is highly specific and sensitive. We recommend official approval of this test to replace the Nelson test.