IgG-antibodies to individual cytomegalovirus proteins and the peripheral blood lymphocyte subset profile in patients with anterior uveitis of varying severity

Abstract

Background. Cytomegalovirus (CMV), a human beta-herpesvirus, persists latently lifelong after infection. CMV reactivation that occurs periodically can cause disease in target organs including the eye, not only in immunosuppressed, but also in immunocompetent people. Due to its immunosuppressive properties, persistent CMV is involved in the pathogenesis of diverse diseases. The aim was to study the features of antibody formation against six individual CMV proteins and to conduct a correlation analysis with parameters of peripheral blood lymphocyte profile in patients with anterior uveitis of varying severity (without hypopion-mild course, with hypopion-more severe course). Materials and methods. 36 patients with anterior uveitis were examined. Group I consisted of 20 patients without hypopion, group II 16 people with hypopion. No characteristic features of CMV anterior uveitis (elevated intraocular pressure, stromal iris atrophy) were found. Blood serum anti-CMV IgG antibodies (markers of chronic infection) were measured by ELISA, antibodies against individual recombinant CMV antigens were assessed by Line-Immunoassay specific to the main non-structural immediate early protein (IE), DNA-binding phosphoprotein p52, phosphoproteins of the tegument p150, p65, p28, GB-AD envelope glycoprotein. Lymphocyte subset composition was studied by flow cytometry: T-lymphocytes (CD3+), T-helper cells (CD3+CD4+CD8), T-cytotoxic (CD3+CD4CD8+), T-double-positive (CD3+CD4+CD8+), natural killers (CD16+CD56+), B-lymphocytes (CD19+). Statistical analysis was performed using StatTech v. 3.0.2 program (Stattech LLC, Russia). Results. In mild anterior uveitis, there was observed a significantly increased percentage of CD16+CD56+ and a decreased absolute number of CD3+CD8+ compared with anterior uveitis of a more severe course. Only in the group of patients with hypopion (more severe course) there was a direct significant correlation between level of antibodies against IE, p65, p28 antigens and percentage of double-positive cells (CD3+CD4+CD8+) as well as an negative significant relationship between the level of antibodies against IE, p65 and p52 antigens and CD19+ lymphocytes. Conclusion. The data obtained are consistent with few reports on the role of double-positive lymphocytes in the pathogenesis of severe forms of some viral diseases. Further studies are needed to assess an effect of individual viral antigens on CD3+CD4+CD8+ level in patients with chronic CMV infection to confirm the role of double-positive lymphocytes in the pathogenesis of a more severe course of anterior uveitis.