[Importance of looking for specific IgM in serological investigations for syphilis].

Syphilis is still a quite common infection often lacking clinical symptoms and sometimes ignored. Serological tests have peculiar importance in order to settle the diagnosis and therapy. Traditional tests as VDRL and TPHA cannot clearly define the clinical pattern because these tests remain positive for a long period of time. Moreover they can prove the recovery of the patients only if they continue to give low titres. The immunofluorescence test FTA ABS, that raised interest at its outset, has low sensitivity against IgM specific antibodies and defines serological state of patients only in 50% of the cases. The reading of this test remains subjective. The authors intend to verify the importance to detect the IgM specific antibodies to assume medical and legal decisions in unknown subjects, without clinical knowledge. 20,000 sera of normal subjects and of risk group have been assayed. Specific IgM are absent in 60 clinically recovered subjects with VDRL and TPHA still positive, specific IgM are present in 15 cases of Syphilis under treatment and also in 15 subjects with unknown Syphilis. The results show that: 1) IgM specific antibodies for Syphilis are not detectable in patients under a long term antibiotic treatment while the traditional serological tests (VDRL, TPHA) are positive; 2) they are present in patients under treatment with still active infection; 3) they are also present in patients with ignored infection, never treated. In conclusion the Authors consider important to include in the panel of Syphilis testing new assays for the detection of specific IgM antibodies. This is particularly important in subjects under treatment and also in unknown subjects.