CYTOMETRIC ASSESSMENT OF THE CELLULAR COMPARTMENT OF THE IMMUNE SYSTEM IN PATIENTS AFTER END-TO-END KERATOPLASTY

Abstract

The graft rejection reaction, especially in patients from the "high risk" group, is a complex immunological process that remains an urgent problem in ophthalmology. The cornea, despite its immunological privilege, loses its protective barriers under certain conditions (vascularization, inflammation), which leads to the development of an immune response against the transplant. The key mechanisms of rejection are activation of T-lymphocytes (CD4+ and CD8+), as well as an imbalance between effector and regulatory immune cells. Modern methods of immunological monitoring, including analysis of T-cell populations, make it possible to detect signs of rejection in a timely manner and adjust therapy to improve long-term transplant results. The aim of the study was to conduct a comparative cytometric analysis of the population and subpopulation composition of blood lymphocytes in patients after end-to-end keratoplasty.

Materials and methods. The study involved 46 patients who underwent end-to-end keratoplasty, who were divided into two subgroups: those with transplant rejection (n=25) and those with successful engraftment (n=21), as well as a control group of 21 healthy volunteers. The immunological analysis included venous blood sampling and quantitative determination of lymphocyte subpopulations by flow cytometry using a Navios cytofluorimeter (Beckman Coulter, USA) and CD45+ and CD46+ markers. Key populations of lymphocytes, including T helper cells, cytotoxic T lymphocytes, NK cells, B lymphocytes, and activated T cells, were studied to identify differences in the immune status of patients. Results. Comparative cytometric analysis of the population and subpopulation composition of peripheral blood lymphocytes in "high-risk" patients with graft rejection showed a number of significant changes in the form of an increase in the total number of T-lymphocytes, T-helper cells, T-cytotoxic, T-lymphocytes with markers of early and late activation, which indicates the key role of T-cell the role of immunity in the mechanisms of development of late cellular rejection reactions.  Conclusion. 1. The data obtained demonstrate the involvement of systemic cellular mechanisms in the implementation of the rejection reaction of the native corneal allograft and dictate the need for a more detailed study of the T-cell response of the immune system. 2. Cytometric assessment of subpopulations of immunocytes makes it possible to identify early signs of immune activation associated with rejection and opens up new opportunities for the development of personalized and effective treatment strategies aimed at improving transplant outcomes.