Abstract
Purpose:
Numerous studies report anomalous frequencies and defects in function of regulatory T cells in patients with neurodegenerative disorders. To gather first hints, whether changes in this cell group can also be detected in glaucoma patients, with this experimental study, we wanted to investigate whether the number of CD4(+)CD25(+)T cells varies in patients suffering from primary open-angle glaucoma and healthy controls.
Methods:
In this non clinical trial, blood samples in heparinised tubes (20ml) were collected from 8 healthy individuals and 8 age-and gender-matched primary open angle glaucoma patients, after informed consent had been obtained and approval of the local ethics committee. After dilution with phosphate-buffered saline, the peripheral blood mononuclear cells were prepared by density gradient centrifugation over Ficoll-Paque. The cells were stained with FITC-conjugated anti-CD4 and PE-conjugated anti-CD25 (Miltenyi Biotec; Bergisch-Gladbach, Germany) in single and double staining procedures. FACS analyses were performed by gating 200 000 lymphocytes per measurement based on forward/side scatter (FACS Calibur Flow cytometer). Measurements were performed in quadruple for each sample (n=32 measurements per group). Statistical analysis was performed using the student’s t-test. The level of significance was set at p < 0.05. Results are expressed as mean value ± standard error of the mean.
Results:
The mean percentages of CD4(+)CD25(+) T cells of all CD (+) T-Lymphocytes was detected at 9,50% in glaucoma patients with a standard deviation of ± 2,46 %. In healthy controls a significant smaller percentage of CD4(+)CD25(+) T cells of all CD (+) T-Lymphocytes was detected with 6,40% and a standard deviation of ± 1,96%. The student’s t-test calculated a significant difference between both groups of p = 0.014.
Conclusions:
In this pilot study we were able to find increased numbers of CD4(+)CD25(+) T cells in glaucoma patients. Although these markers are not exclusively specific for Tregs, these results could be a hint for elevated Treg levels in glaucoma patients. Tregs inherit suppressive functions which possibly are attenuated in glaucoma patients. These studies underline the hypothesis of an immunologic involvement in glaucoma via the cellular immunity.
Keywords: 555 immunomodulation/immunoregulation