Abstract: Objective To investigate the effects of DNaseⅠ-treated streptococcal antigens on peripheral blood mononuclear cells(PBMC)proliferation in psoriasis patients.Methods PBMC from 15 patients with psoriasis and 10 healthy controls were stimulated with three concentrations(2,10,25μg/mL) of streptococcal antigens(SA), nd DNaseⅠ-treated streptococcal antigens(DNaseⅠ-SA).After 72 h of culture,cellular proliferation was determined by ³H thymidine incorporation.Results The DNaseⅠ-SA,at all the concentrations tested,was less potent than the corresponding concentrations of SA(P<0.01)in stimulating the proliferation of PBMC from psoriasis patients.In normal controls,no difference was observed between 25μg/mL of DNaseⅠ-SA and SA(P>0.05),however,the lower concentrations(2,10μg/mL) of DNaseⅠ-SA were less potent than those of SA(P<0.05).The proliferation level of PBMC in response to 25μg/mL of SA was significantly higher in patients than in normal controls(P<0.05),while there was no significant difference in response to DNaseⅠ-SA of all three concentrations between patients and normal controls(P>0.05).Also,the extent of proliferation response to SA and DNaseⅠ-SA was higher in the patients than in the controls(P<0.05).Conclusion Streptococcal DNA may participate in the development of psoriasis caused by infection.

Key words: Psoriasis, Streptomyces, DNaseⅠ, Cell proliferation