Reduction in the inflammatory markers CD4, IL-1, IL-6 and TNFα in dogs with keratoconjunctivitis sicca treated topically with mesenchymal stem cells

Keratoconjunctivitis sicca (KCS) is of predominantly immune-mediated origin. Dogs are an excellent model for understanding this disease, as the origin of KCS in dogs is like that in humans. The objective of this study was to localize and quantify immunological markers, such as CD4 lymphocytes, interleukin (IL)-1, IL-6 and tumor necrosis factor alpha (TNFα), before and after topical treatment with mesenchymal stem cells (MSCs). Twenty-two dogs positive for KCS were topically treated with 50 μL (1 × 106 MSCs) in the conjunctival sac and were evaluated for 6 months. The levels of the markers CD4, IL-6, IL-1 and TNFα were analyzed in conjunctival biopsy and cytology of the third eyelid gland by immunohistochemistry and immunocytochemistry. The results showed that before treatment, there was marked expression of all the markers (CD4, IL-6, IL-1 and TNFα), and after 6 months, there were significant (p