Flow Cytometry Analysis of Peripheral Blood Lymphocytes in Patients with Choroidal Melanoma

Abstract

To evaluate peripheral blood lymphocyte subpopulations in patients with choroidal melanoma. In this prospective study, peripheral blood lymphocytes of 226 patients afflicted with choroidal melanoma were analyzed by flow cytometry and compared with those of 49 age-matched and gender-matched control subjects. Subpopulations of peripheral blood lymphocytes were further identified by monoclonal antibodies specific to cell-surface markers. Statistical analysis was performed by a Student t test. There was no overall difference between the patients with choroidal melanoma and the control subjects with regard to peripheral blood lymphocyte subpopulations. However, when the patients were divided into subgroups based on their clinical characteristics, differences in natural killer (NK) cell population and activated T cells were noted in two subgroups. Patients with ciliary body involvement showed a statistically significant reduction in NK cells (194 +/- 101 vs 260 +/- 178 per mm3; P = .01). The number of activated T cells in this subgroup of patients was increased but not statistically significantly (7.32 +/- 4.79 vs 6.09 +/- 4.34 per mm3; P = .08). In patients with extrascleral extension, a statistically significant increase in activated T cells was noted (9.84 +/- 7.41 vs 6.25 +/- 4.3 per mm3; P = .02). The NK cells in this subgroup of patients were also reduced, but the reduction did not achieve statistical significance (178 +/- 123 vs 248 +/- 167 per mm3; P = .24). We noted statistically significant differences in peripheral blood lymphocytes in two subgroups of patients with clinically less favorable choroidal melanoma.