According to Textbook of Microbiology and Immunology 2e, Subhash Chandra Parija, pg.no; 375
These(reaginic) antibodies do not appear in early primary syphilis, latent acquired syphilis of long duration, and late congenital syphilis. Therefore, Venereal Disease Research Laboratory (VDRL) and other tests may show false negative reactions during these conditions.
Isn't latent syphilis detected by presence of reaginic antibodies? Then why is it said that it does not appear in long duration?
Why antibodies are not produced in late congenital syphilis?