Evaluation of the expression of T helper lymphocytes markers associated with Th1, Th2, Th17, and Treg cells in primary pterygium biopsies

Various proinflammatory cytokines and growth factors have been implicated in the pathogenesis of pterygium (Pt); however, the effect of cytokines produced by helper T lymphocytes (Th) has been poorly studied. To date, only interleukin 4 (IL-4) from Th lymphocytes has been linked to Pt recurrence. Therefore, this study aimed to evaluate the expression of Th cytokines and Th transcription factors in primary Pt. Methods: Pt biopsies were obtained from 28 eyes of 28 Mexican patients undergoing primary excision of Pt with conjunctival autograft. Conjunctival biopsies of eight patients undergoing cataract surgery were used as the control group. Gene expression of Th cytokines interferon gamma (IFN-γ), interleukin (IL)-13, IL-17, IL-10-, as well as gene expression of Th transcription factors T-bet, GATA3, Foxp3, and RORγt, was analyzed by real-time RT-PCR. results: We found decreased expression of markers T-bet, GATA3, RORγt, IFN-γ, IL-13, and IL-10 in Pt. We found a six-fold increase in the expression of IL-17 and Foxp3 in Pt compared to healthy conjunctiva (p < 0.0001); this increase was dependent on Pt size. Conclusions: The increased expression of IL-17 and Foxp3 in Pt samples suggests the presence of IL-17+ Foxp3+ Th lymphocytes, a subset of the Th population with the ability to suppress T cell proliferation and promote tumor progression. Therefore, IL17+ Foxp3+ Th cells may be involved in the occurrence and growth of Pt.