The Immune Response To 3 Different Therapies In Herpetic Stromal Keratitis

Abstract

Purpose: : To evaluate and compare the immune response by cytokine profile on peripheral blood mononuclear cells (PBMC) from patients with herpetic stromal keratitis to 3 different schedules of treatment: Group 1: Topical prednisolone acetate 1% (PA), Group 2: PA + Topical cyclosporine A 0.1% (CsA) and Group 3: PA + Dyalyzable Leukocyte Extracts (DLE).

Methods: : A prospective, comparative, transversal study was done. We determined on PBMC the expression of CD4+,CD8+, intracellular cytokines (IFN-γ/IL-4) and proinflammatory cytokines (TNF-α/IL-6/IL-1b) in culture supernatants (SN) before/after polyclonal stimuli. Blood samples were taken before and 8 weeks of initiating the treatment. Results were obtained by flow-cytometry and ELISA.

Results: : 12 patients divided in the 3 different groups, PA (n=4, control group), CsA (n=4) and DLE (n=4). Percentage (%) of CD4+ IFN-γ+ T cells in PA 20%, CsA 18%, DLE 38% after treatment. The CD4+IL-4+ T cells in PA 7 ,CsA 6, DLE 7%, CD8+IFN-γ+ in PA 36.1,CsA 35.9, DLE 36.1% of CD8+IL-4+ in PA 4.29, CsA 4.0, DLE 2.9Cytokines in SN (pg/ml): TNF-α in non-stimulated cells (NSC) from PA 225.4 vs 3727 in stimulated cells (SC) from PA; TNF-α in NSC from CsA 170 vs 3641 in SC from CsA; TNF-α in NSC from DLE 159 vs. 3423 in SC from DLE; IL-1β in NSC from PA 44.6 vs. 78.4 in SC from PA; IL-1β in NSC from CsA 42 vs 73.6 in SC from CsA; IL-1β in NSC from DLE 36.1 vs 61.3 in SC from DLE; IL-6 in NSC from PA 303 vs 512 in SC from PA, IL-6 in NSC from CsA 284 vs 506 in SC from CsA group, IL-6 in NSC from DLE 265.6 vs 477.1 in SC from DLA group.

Conclusions: : The immune response against HSV is mediated by Th1 cells. Previous studies have shown that corneas infected with HSV attract CD4+T cells to the site of lesion. The 3 groups show an increase in CD4+ IFN-γ+ T cells after the treatment as the natural evolution of HSK, but the DLE group increase the expression in CD4+ IFN-γ+ T cells 1.9 times more than the PA group (p=0.002). The systemic immunological changes observed in this study suggest that DLE could act as a systemic immunological booster, inducing Th1 response by CD4+IFN-g+ T cells. We found IL-1b as the most important proinflammatory cytokine increased after in vitro stimuli in the 3 groups with HSK. These results suggest that peripheral IFN-γ+ cells could migrate to the human cornea and to collaborate with residents or infiltrating cells to produce proinflammatory cytokines, increasing the inflammatory damage as it has been demonstrated in animal models.

Keywords: keratitis • immunohistochemistry • herpes simplex virus