Serum IgA, IgM and IgG levels, assayed by the radial immuno diffusion method (Mancini, Carbonara and Heremans, 1965) of 57 caucasian men with untreated early syphilis were compared with those of 16 age-matched controls.
In all patients the diagnosis was confirmed by a positive darkfield examination and/or positive TPI test.
Accepting a level of significance of ~ <0.05, there is already a significant raise in both IgG and IgM levels in the sero-non reactive primary stage. Serum levels of all three immuno-globulins sharply increase in the sero-reactive primary stage. The serum levels of IgM and IgG remain raised during the secondary and early latent stage. IgA however shows a shorter lived elevation, since its level decreases significantly in the secondary stage, as compared to the seroreactive primary stage.
After six weeks of therapy in which 30 millions I.U. of penicillin were given IgG and IgM levels showed a significant decrease in the secondary stage only. Six weeks after termination of therapy however there is still a significantly raised IgM level, in contrast to IgG level.
Furthermore, from comparison of the proportional increase of basic IgG, assayed by agar gel electrophoresis (Wieme, 1965) and total IgG it would appear that the increase of total serum IgG results from preferential synthesis of basic IgG immunoglobulins. The serum level of basic IgG is also more strongly affected by penicillin therapy than total IgG level.