Determination of chlamydial load and immune parameters in asymptomatic, symptomatic and infertile women.

The regulation of immune response and chlamydial infectious load in the cervix of human females is largely unknown. Infectious load in terms of inclusion-forming units (IFUs) was determined by quantitative cultures in Chlamydia-positive women, in asymptomatic women, women with mucopurulent cervicitis (MPC) and women with fertility disorders (FD). CD4(+), CD8(+), CD14(+) cells, myeloid and plasmacytoid dendritic cells (mDCs and pDCs) in the cervix were quantified by flow cytometry. Cervical cytokines, levels of beta-estradiol and C-reactive protein (CRP) in serum and cervical immunoglobulin A antibody to chlamydial major outer membrane protein antigen, chlamydial heat shock protein 60 and 10 antigens were measured by an enzyme-linked immunosorbent assay. In asymptomatic women, chlamydial load showed significant positive correlations with CD4, mDCs, interleukin-12 (IL-12) and IL-2; however, negative correlations were found with CD8 and IL-8 levels. In women with MPC, chlamydial IFUs correlated positively with CD8, pDC number, IL-8, CRP and interferon-gamma (IFN-gamma). In women with FD, chlamydial load showed a significant positive correlation with the pDC number, IL-10 and estradiol level and a negative correlation with CD4 and IFN-gamma. Overall, these results suggest that the interplay between chlamydial infectious load and host immune responses may be the deciding factor for the clinical condition presented during Chlamydia trachomatis infection.