Table 1.
Clinical and laboratory characteristics of 100 healthy donors and 431 syphilis patients.
Table 2.
Clinical and laboratory features for 100 neurosyphilis patients.
Figure 1.
Treg activity in the peripheral blood of early and serofast syphilis patients.
(A) Peripheral blood mononuclear cells (PBMC) were stained for flow cytometric analysis and lymphocytes were gated according to forward and side scatter characteristics. Representative plots show the gates of CD4+ CD25high and CD4+ Foxp3+ T cells in the lymphocyte gate. CD25 and Foxp3 expression among CD4+ T cells are also shown. (B) The percentage of CD25high and Foxp3+ among CD4+ T cells in peripheral blood of healthy controls, and in patients with primary, secondary, latent and serofast syphilis. Individual frequencies for every patient analyzed are shown. (C) CD4+ CD25+ T cells and CD4+ CD25− T cells were purified from peripheral blood of healthy donors, and patients with primary, secondary, latent and serofast syphilis. The mean percent inhibition of the proliferative response by CD4+ CD25+ T cells derived from three to five individuals per group is shown. Results are representative of three independent experiments. (D) Serum concentrations of TGF-β were measured in healthy controls, and in patients with primary, secondary syphilis, latent, and serofast syphilis. Results represent the mean or the mean ± SEM. (E) Correlation of serum TGF-β concentration with circulating CD4+ CD25high Treg frequencies in syphilis patients (n = 176). Each dot represents an individual patient. B, Kruskal-Wallis test; C and D, One-way ANOVA; E, Pearson's correlation. *, P<0.05; **, P<0.01; ***, P<0.001.
Figure 2.
Association of circulating Treg numbers with serum RPR titers in primary, secondary, latent and serofast syphilis patients.
Serum RPR titers are plotted against circulating CD4+ CD25high Treg frequencies in primary (A, n = 64), secondary (B, n = 96), latent (C, n = 86) and serofast (D, n = 43) syphilis patients. Each dot represents an individual patient. The straight line in each graph is the result of linear regression analysis. Pearson's correlation coefficients (r) and P values are shown.
Figure 3.
Treg frequencies in peripheral blood of neurosyphilis patients.
The percentage of CD25high (A) and Foxp3+ (B) among CD4+ T cells in peripheral blood of healthy controls, and syphilis patients without (including primary, secondary, latent and serofast syphilis) and with (including both asymptomatic and symptomatic neurosyphilis) neurological involvement are shown. The percentage of CD25high (C) and Foxp3+ (D) among CD4+ T cells in peripheral blood of different types of neurosyphilis patients. Individual frequencies for every patient analyzed are shown. Results represent the mean ± SEM. A and B, Kruskal-Wallis test; C and D, One-way ANOVA. *, P<0.05, ***, P<0.001.
Table 3.
Absolute number of leukocytes, percentage and numbers of CD4+ T cells, Tregs, and TGF-β levels in CSF from different types of syphilis patients.
Figure 4.
Schematic diagram summarizing the role of Treg in syphilis.
APC, antigen presenting cells; Th1, T helper cell type 1; Treg, regulatory T cells; CSF, cerebrospinal fluid; CNS, central nervous system; DC, dendritic cells.