Studies of syphilitic antibodies. 3. Anamnestic reactions and 19S predominance of the anti-lipoidal antibodies in aged persons.

Syphilitic anti-lipoidal antibodies as detected by the standard tests for syphilis (STS) are usually recovered in both yM (19S) and yG (7S) globulin fractions (Davis, Moore, Kabat, and Harris, 1945; Laurell and Malmqvist, 1961; Aho, 1967), whereas substances responsible for biologic false positive (BFP) reactions are found in most instances solely in the yM globulin fraction (Aho, 1968). Syphilis is a disease usually acquired in early adult life. Because of the prolonged immunogenic stimulation one might expect that the syphilitic antibodies at an advanced age would be mainly of yG globulin type. Aged persons may develop BFP reactions without any known cause except ageing per se (Tuffanelli, 1966). The present study was prompted by the accidental discovery of an elderly person with adequately treated old syphilis who exhibited rising titres in standard serum tests for syphilis. The frequency of such rising titres was studied and fractionation experiments were conducted to compare the distribution of anti-lipoidal and antitreponemal antibodies.