Fig. 1.

Visits with enzyme-linked immunosorbent assay (ELISA) and tests for chlamydial infection in Group I subjects. Endocervical interleukin (IL)-2 (a) and IL-12 (b) concentrations in adolescent females with at least four visits of data available (Group I, n = 281). Cytokine levels are compared between chlamydia-positive (CT⁺) and chlamydia-negative (CT⁻) subjects for each of the four visits available. The interquartile ranges (boxes), medians (bars within boxes) and entire ranges (vertical lines) are shown here. P-values are based on non-parametric Mann–Whitney U-test between patient groups within each visit.