Measurement of peripheral blood lymphocyte subsets in patients with renal cell cancer treated with postoperative adjuvant interferon-α therapy

Interferon-α (IFN-α) was prophylactically administered to the patients with high-stage renal cell cancer after radical nephrectomy. Seventeen patients who were at high risk for recurrence of disease received 500 x 10⁴ units of IFN-α, 2 or 3 times per week for 2 years. Median followup was 21.5 months. Of the patients 4 (23.5%) revealed pulmonary metastasis with or without local recurrence. The administration of IFN-α for 2 patients was discontinued because of side effects. One patient showing pulmonary metastasis has survived, 2 died of cancer and 1 of an unrelated cause. Immunological changes were analyzed by measurement of peripheral blood lymphocyte subsets. Two-color flow cytometry was used to evaluate the lymphocyte subsets consisting of suppressor T lymphocytes (CD8⁺ CD11b⁺), cytotoxic T lymphocytes (CD8⁺ CD11b^-), helper T lymphocytes (CD4⁺ CD45 RA⁺), suppressor inducer T lymphocytes (CD4⁺ CD45 RA^-), natural killer cells (CD3^- CD56⁺), natural killer T cells (CD3⁺ CD56⁺), activated CD8 positive cells (CD8⁺ HLA-DR⁺) and activated CD4 positive cells (CD4⁺ HLA DR⁺). The number of suppressor T lymphocytes and activated CD8 positive cells increased in the recurrent cases. In contrast, suppressor T lymphocytes gradually decreased after IFN-α treatment, and no evidence of cancer was found in the remaining cases.