Retinoblastoma is a malignant retinal tumor characterized by an aggressive clinical course, with frequent recurrences and the emergence of new foci even during chemotherapy.

OBJECTIVE

This study investigated the subpopulation composition of peripheral blood lymphocytes in children with newly diagnosed untreated retinoblastoma.

MATERIAL AND METHODS

A total of 24 children (48 eyes) were examined between December 20, 2023, and September 1, 2024; retinoblastoma was diagnosed in 28 eyes. Immunological assessment was performed using whole blood samples. Lymphocyte subpopulations were analyzed by flow cytometry on a BD FACS Canto II (Becton Dickinson, USA) using the Multitest 6-Color TBNK Reagent monoclonal antibodies in BD TruCount tubes (Becton Dickinson, USA).

RESULTS

Analysis of the lymphocyte subpopulation profile revealed an imbalance in key cellular components of both the innate (natural killer cells, NK) and adaptive (T- and B-lymphocytes) branches of the immune system. Significant alterations were observed in NK lymphocytes (CD16⁺CD56⁺), with decreased absolute and relative counts identified in 54.5% and 45.5% of children, respectively. More severe disease stages were associated with marked abnormalities in NK cell populations and adaptive immune cell subsets (T- and B-lymphocytes); in this group, a reduction in the absolute number of NK cells was observed in 60% of patients, while nearly one-third of these children exhibited reduction in absolute and relative counts of B-lymphocytes (CD19⁺), as well as in key regulatory subpopulations of T-helper and T-cytotoxic lymphocytes.

CONCLUSION

The findings indicate significant deviations in the cellular immune status (lymphocyte subpopulation composition) of children with newly diagnosed untreated retinoblastoma.