Cellular immunity and lymphocyte activation markers in idiopathic optic neuritis (ON) and non-arteritic anterior ischemic optic neuropathy (NAION)

Abstract

Objectives: To identify cellular immunity features and lymphocyte activation marker expression in idiopathic ON (papillitis) and NAION. Methods: The study included 27 patients with ON (mean age 37.8 ± 11.3 years), 7 with acute NAION (54.2 ± 8.1 years), 31 with chronic NAION (52.1 ± 12.1 years), and 27 healthy controls (42.7 ± 12.9 years). Activation marker expression on peripheral blood lymphocytes was assessed by immunohistochemical methods. Results: Absolute leukocyte count was 5.8 × 10⁹/L (95% CI, 5.1–6.2 × 10⁹/L) in acute NAION, 5.4 × 10⁹/L (95% CI, 4.7–6.1 × 10⁹/L) in chronic NAION, 8.5 × 10⁹/L (95% CI, 7.3–9.7 × 10⁹/L) in idiopathic ON, and 5.4 × 10⁹/L (95% CI, 5.1–5.7 × 10⁹/L) in controls. Peripheral blood lymphocyte count, presented as median (Q25–Q75), was 1.98 (1.7–2.26), 2.01 (1.2–2.48), 2.43 (1.98–2.82), and 1.59 (1.25–1.89) cells/µL, respectively. CD3+ lymphocyte levels were 1122 (991–1379), 1324 (748–1544), 1805 (1188–2080), and 1007 (772–1104) cells/µL, respectively; CD4+ levels were 902 (722–1062), 1031 (555–1205), 1325 (886–1390), and 645 (575–736) cells/µL; CD8+ levels were 252 (221–322), 265 (208–283), 395 (282–500), and 274 (198–322) cells/µL; CD16+ natural killer cell levels were 331 (235–542), 362 (232–445), 352 (146–330), and 196 (102–233) cells/µL. CD54 (ICAM-1) levels were 28.8 ± 2.5%, 28.9 ± 2.6%, 29.2 ± 1.7%, and 8.5 ± 2.0%, respectively, and CD95 levels were 26.7 ± 2.7%, 25.9 ± 2.0%, 22.8 ± 4.3%, and 9.6 ± 2.8%, respectively. The Kruskal–Wallis test showed significant intergroup differences in leukocyte, lymphocyte, CD3+, and CD4+ levels (p < 0.001), with highest values in idiopathic ON. CD4+ levels were increased by 40% in acute NAION (p = 0.03), 60% in chronic NAION (p = 0.003), and 2.05-fold in ON (p < 0.05) versus controls. CD8+ levels were 44% higher in ON (p = 0.04), and CD16+ levels were 69% (p = 0.04) and 84.6% (p = 0.001) higher in acute and chronic NAION, respectively, than in controls. CD54 and CD95 were elevated in all patient groups versus controls (p < 0.05), and CD95 was 14.3% higher in acute and chronic NAION than in ON (p < 0.05). Conclusions: Idiopathic ON is characterized by higher CD3+, CD4+, and CD8+ lymphocyte levels, whereas NAION is associated with elevated CD4+ levels and a more pronounced increase in NK cells. CD54 (ICAM-1) and CD95 were elevated in both conditions, while higher CD95 levels in NAION may indicate more pronounced apoptotic activity.