Lymphocyte subset alterations in nodes regional to human melanoma.

The lymphocyte subpopulations in tumor-draining lymph nodes of melanoma patients were determined using two-color flow cytometry. Data were analyzed according to: (a) the staging of the melanoma; (b) whether or not the nodes contained tumor; and (c) their distance from the primary tumor. Compared with Stage I patients (without metastasis), uninvolved nodes of stage II patients (with nodal metastases) had a significant decrease in helper/inducer (CD4+) T-cells (P less than 0.001), with a corresponding increase in cytotoxic/suppressor (CD8+) cells (P less than 0.001) and Leu 19+ natural killer (CD56+) cells (P less than 0.01). In some patients the presence of tumor within a node was associated with a large decrease in CD3+ total T-cells, whereas in others tumor involvement had little influence on lymphocyte phenotypes. When analyzed by distance from the primary tumor, nodes closest to tumor in Stage I patients contained a smaller percentage of CD19+ B-cells. In Stage II, tumor-free nodes nearest to tumor showed an increase in CD19+ cells, but statistical significance was not reached. CD56+ natural killer cells increased progressively in nodes near tumor and were more numerous in Stage II uninvolved nodes compared with Stage I nodes. Alterations in phenotypically defined lymph node lymphocytes occur in nodes regional to melanoma as the disease progresses, as growth of metastases occurs, and in tumor-free nodes nearest to tumor. These alterations may be essential to the establishment and progression of metastases.