Figure 3. Correlations between Right Eye Conjunctival Gene Transcript Levels Reveal Linked Cytokine Responses and the Relationship to Control of Pathogen Load.

Abundance of IFN-γ, IL-10, and IDO relative to HPRT expression after log₁₀ transformation. Correlation coefficients were calculated by Spearman's rank correlation and trend lines fitted by locally weighted polynomial regression.

(A) Strong positive correlation between the conjunctival expression of IDO and IFN-γ in individuals with infection (n = 69) or without infection (n = 238).

(B) Strong positive correlation between the expression of IFN-γ and counter inflammatory IL-10 in infected (n = 69) and uninfected individuals (n = 238).

(C) Relative abundance of IDO and the load of pathogen (chlamydial 16S rRNA) in the conjunctiva. A weak positive correlation was found between pathogen load and IDO expression in clinically normal individuals (n = 42) (mean pathogen loads are lower in this group; Table 2). In contrast, the relationship between IDO expression and pathogen load is weakly negative or absent in individuals with co-incident clinical signs of trachoma (n = 29) (pathogen loads are highest in this group; Table 2).

CT, C. trachomatis.