miRNAs that associate with conjunctival inflammation and ocular Chlamydia trachomatis infection do not predict progressive disease.

08 Feb 2017
Derrick T, Ramadhani AM, Mtengai K, Massae P, Burton MJ, Holland MJ.

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 Chlamydia 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 was 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 4-year longitudinal study. Chlamydia trachomatis infection was diagnosed by droplet digital PCR and expression of miR-155, miR-184, miR-1285 and miR-147b was tested by qPCR.

Individuals were assessed for incidence and progression of conjunctival scarring by comparison of conjunctival photographs taken at baseline and 4 years later. miR-184 and miR-155 were strongly associated with inflammation and infection at baseline; however, no miR was associated with 4-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.