The pattern and level of cytokines secreted by Th1 and Th2 lymphocytes of syphilitic patients correlate to the progression of the disease

The results of our previous work indicated that cell-mediated immune respon se, of importance in protection against Treponema pallidum, is distinctly i nhibited at certain periods of syphilitic infection. Considering that cytok ines, produced by Th1 lymphocytes, take part in this response and that thei r secretion may be regulated by cytokines of Th2 lymphocytes, we examined i f, and in which stages of syphilis, such a regulation may exist. In this st udy we have examined the ability of cells to produce IL-2, IFN and TNF (Th1 or Th1 like cytokines) as well as IL-6 and IL-10 (Th2 or Th2 like cytokine s). It was found that cells of syphilitic patients were able to produce IL- 2, IFN, TNF, IL-IO and weakly IL-6 already in primary seronegative syphilis . At the same stage of syphilis, but seropositive, ability of Th1 lymphocyt es to produce cytokines reached the highest values, whereas the cells produ cing IL-10 lost this ability. The cells producing IL-G and MIF had the high est ability in secondary early syphilis. In this stage of syphilis again sl ightly increased the ability of cells to secrete IL-10, which reached the h ighest value in early latent syphilis. The growing ability to produce IL-6 and IL-IO was accompanied with a diminished production of IL-2, IFN and TNF nearly in all stages of syphilis. Only MIF, in contrast to other cytokines , was produced in late syphilis without distinct changes. The greatest supp ression of Th1 lymphocytes to produce cytokines and cells to secretion of M IF was found in early latent syphilis when the level of IL-IO in cell cultu re supernates was the highest. High ability of Th2 lymphocytes to cytokines secretion in late syphilis and low ability of Th1 ones, which are very imp ortant for cell-mediated immune response, may be the reason for facilitatin g T. pallidum multiplication and development of latent stages of disease de spite presence of immunologically competent cells. (C) 2000 Federation of E uropean Microbiological Societies. Published by Elsevier Science B.V. All r ights reserved.