We previously showed that conjunctival miR-147b and miR-1285 were upregulated in Gambian adults with inflammatory scarring trachoma and miR-155 and miR-184 expression was strongly associated with conjunctival inflammation and ocular C. trachomatis infection in children from Guinea Bissau. We investigated whether the single or combined expression of miR-147b, miR-1285, miR-155 and miR-184 were able to identify individuals with increased risk of incident or progressive scarring trachoma. Conjunctival swab samples were collected from 506 children between the ages of 4 and 12 living in northern Tanzania. These 506 samples formed the baseline sample set of a four-year longitudinal study. C. trachomatis infection was diagnosed by droplet digital PCR and expression of miR-155, miR-184, miR-1285 and miR-147b were tested by qPCR. Individuals were assessed for incidence and progression of conjunctival scarring by comparison of conjunctival photographs taken at baseline and four years later. miR-184 and miR-155 were strongly associated with inflammation and infection at baseline, however no miR were associated with four-year scarring incidence or progression. miR-184 expression was more strongly downregulated during inflammation in non-progressors relative to progressors, suggesting that a disequilibrium in the efficiency of wound healing is a significant determinant of progressive conjunctival fibrosis.

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