Correlation of regional lymph node in vitro antitumor immunoreactivity histology with colorectal carcinoma

Lymph nodes from resected specimens of human colorectal carcinoma were investigated for in vitro lymphocyte cytotoxicity against primary cultures of autologous tumor cells. Regional lymph node lymphocytes were cytotoxic in 32 of 142 cases (23%). Altogether 200 nodes were examined and the cytotoxicity correlated directly with sinus histiocytosis, seen in 43 nodes from 35 cases, and with hyperplasia of B- and T-lymphocyte areas combined, seen in 92 nodes from 65 cases. Lymph nodes with combined B- and T-cell hyperplasia were significantly more common in cases of good tumor differentiation. The findings suggest that sinus histiocytosis and hyperplasia of both major lymphocyte populations are morphological expressions of in vitro antitumor immunoreactivity in the regional lymph node.