Purpose: To study and compare the immune response and neopterin levels in the blood in experimental autoimmune uveitis (EAU).

Methods: A model of EAU was created in 30 Chinchilla rabbits. Intravenous and intravitreal injections of normal horse serum were administered for this purpose. Clinical examinations and blood tests were conducted on days 3, 7, 10, 14, and 21. The blood investigation included the determination of neopterin (NP) level, white blood cell counts, lymphocytes, CD3+ , CD4+ , CD8+ , and CD16+ .

Results: The peak in white blood cell count was observed on days 7 and 10 (6.4 ± 0.4 g/L and 6.0 ± 0.3 g/L, respectively), lymphocytes on day 3 (68.3% ± 2.4%, 3.0 ± 0.2 g/L), CD3 + on day 7 (64.9% ± 3.1%, 2,032.5 ± 91.2 cells/µL), CD4 + and CD16 + on day 10 (54.6% ± 3.8%, 2,462.3 ± 60.7 cells/µL and 21.8% ± 1.8%, 691.2 ± 37.1 cells/µL, respectively). All these values did not return to the initial ones. There was a gradual decrease in the CD8 + count from day 3 (12.5% ± 1.1%, 142.8 ± 9.1 cells/µL) with a subsequent gradual return towards normal levels by day 21. NP levels incresed on day 3 (5.2 ± 0.7 nmol/L), sustained on day 7 (5.2 ± 0.8 nmol/L), and started to decrease from day 10 (4.25 ± 1.7 nmol/L) to 2.3 ± 0.5 nmol/L on day 21. The highest correlation was observed between clinical manifestations and NP with a correlation coeffient of 0.799 (95% confidence interval, 0.719–0.858), which was significantly stronger (p < 0.05) than the correlations with other immune response markers. Conclusions: During the modeling of EAU, there is an active immune response and a rapid reaction of NP on inflammation. NP is a significantly more sensitive marker of intraocular inflammation than the immune response. It can serve as a predictor of the onset and development of EAU.

Key Words: Animal, Blood, Immunity, Neopterin, Uveitis

Aim: To investigate the dynamics of the T-cell immune response in rabbits with experimental autoimmune uveitis (EAU) of varying severity. Materials and Methods: The experiment involved two groups of Chinchilla rabbits (15 rabbits in each group). The model of EAU was created. The clinical picture of intraocular inflammation of varying severity was assessed. The determination of the level of white blood cells (WBC), lymphocytes (Lymphs), CD3+, CD4+, CD8+, and CD16+ in the blood of rabbits was conducted.

Results: Group I – moderate and severe uveitis, Group II – uveitis of mild severity. WBC, Lymphs, CD3+, CD4+, CD16+ were elevated and statistically significant in both groups of animals compared to control parameters on all days of the experiment (3, 7, 10, 14, 21 days) (p < 0.001). CD8+ level had a significantly lower count than the control one (p < 0.001). When comparing the two groups, the immune response was more active in Group I, and the number of immune cells did not return to normal by the end of the experiment.

Conclusion: In the case of EAU, the immune response is characterized by the activation of the T-cell immune system, with the intensity of this response depending on the severity of the clinical presentation of uveitis. Various degrees of clinical severity in EAU were obtained using an experimental model employed in our study. A rapid response of the immune system helps to establish a diagnosis and predict the severity of autoimmune uveitis.

Key words: T-cells response, experiment, autoimmune uveitis