Objective: To determine the ability of T lymphocytes and natural killer (NK) cells from patients with systemic sclerosis (SSc) to respond to cytokines and to generate immune effector cells.
Methods: The numbers and percentages of peripheral blood T and NK cells were examined by 2-color flow cytometry, and NK and lymphokine-activated killer (LAK) cell function were measured in 4-hour 51Cr-release assays, in 34 patients with SSc. The patients were categorized into 3 subgroups: 10 had diffuse cutaneous disease of less than or equal to 3 years disease duration, 11 had diffuse cutaneous SSc of greater than 3 years duration, and 13 had limited cutaneous disease.
Results: Baseline and activated NK and T cell numbers and NK activity were normal in SSc patients. However, mean LAK activity was significantly depressed in all SSc subgroups.
Conclusion: Decreased LAK cell function, despite normal numbers of circulating T and NK cells, indicates that SSc patients have poor ability to produce effector cells in response to interleukin-2.