Analysis of lymphocyte subsets in HIV-negative neurosyphilis patients

It is unclear how Treponema pallidum affects the immune response among various lymphocyte subsets in neurosyphilis patients with different clinical stages. In order to determine the immune response by T. pallidum infection, we detected the peripheral blood lymphocyte subsets among 14 asymptomatic neurosyphilis patients, 19 early neurosyphilis patients, 9 late neurosyphilis patients, and 50 healthy persons. The result indicated that the number of CD3+CD8+ lymphocytes was significantly higher in neurosyphilis patients than in the control group (χ2 = 4.427, P = 0.035). The number of CD3+CD8+ lymphocytes was significantly higher in the asymptomatic neurosyphilis group than in the early neurosyphilis group, late neurosyphilis group, and control group (F = 4.644, P = 0.005). The number of NK cells was significantly lower in neurosyphilis patients than in the control group (χ2 = 13.226, P = 0.000). The number of NK cells in neurosyphilis patients with different clinical stages was also lower than in the control group (F = 4.402, P = 0.006). The number of CD3+ lymphocytes, CD3+CD4+ lymphocytes, and B lymphocytes had no difference among the 4 groups. The results indicated that the progression of neurosyphilis may be related to the continued reduction in the number of NK cells and to the continued increase in CD3+CD8+ lymphocytes.