Abstract
BACKGROUND: Allergic conjunctivitis (AC) is one of the most common eye disorders in clinical practice. It has been shown that AC is a disorder mediated by Th2 lymphocytes producing IL-4 and IL-5, where the eye damage is caused by a type I hypersensitivity. It has been suggested in asthma and rhinitis that T regulatory cells (Tregs) CD4(+) CD25(+) FOXP3(+) have been involved in control allergic status, favoring an optimal microenvironment with immunosuppressive cytokines (IL-10, TGF-β). However is unknown if Tregs have a role in human allergic conjunctivitis, thus it was the aim of this study. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated from blood samples of healthy donors (HD) and AC-patients, and then PBMC were labeled with mAbs against CD4, CD25 and FOXP3. Labeled cells were analyzed by flow cytometry. Statistical analysis was performed with GraphPad v.5. RESULTS: AC-patients showed 55-times more CD4(+) CD25(+) cells than HD (P = 0.02). Most of CD4(+) CD25(+) were FOXP3(-) (90 ± 5.4), when we compared MFI of FOXP3 in CD4(+) CD25(+) cells, we observed a decreased expression in AC-patients than HD (28.5 vs 85.36, P = 0.02). CONCLUSIONS: Despite we observed higher frequency of CD4(+) CD25(+) in AC-patients, these cells were FOXP3(−), more interesting, the few cells FOXP3(+) showed a diminished MFI. These data suggest that allergic conjunctivitis status could be related with a regulatory dysfunction, as has been suggested in asthma and rhinitis.