Morphology of draining lymph nodes after local immune stimulation with C. parvum: comparison of pelvic nodes in carcinoma of cervix and popliteal and inguinal nodes of guinea-pig.

Morphological changes are described in pelvic lymph nodes excised 10 days after C. parvum (CP) treatment of patients with cervical carcinoma. Guinea-pig popliteal and inguinal lymph nodes were investigated from Days 1 to 10 after an injection of 70 micrograms CP into the footpad. Eosinophils were detected from the first few hours after stimulation, initially in the marginal sinus, then in the medullary sinuses and subsequently in the efferent lymphatics. From Day 2 to Day 6, histiocyte accumulations with the appearance of epithelioid cells were found mainly in subcapsular and interfollicular areas, and small granulomas were also seen in the paracortex. The granuloma formation in the lymph node was considered as an indication of the activation of histiocytes. Besides small granulomas in the paracortex, activated interdigitating cells, surrounded by scattered lymphoblasts and eosinophils, were also present. We considered this lymphoblastic response and eosinophilic accumulation as likely to be due to blastogenic factor and eosinophil stimulation promotor. Eight to 10 days after CP stimulation, the macrophage lymphoblast eosinophil response was replaced by a B-cell reaction: germinal-centre activation and medullary plasma cells. Such a B-cell reaction was also found in the human pelvic nodes removed at operation, but this reaction could not be attributed to CP treatment alone, since cervical-carcinoma patients not treated with CP also showed such reactions. In contrast, pelvic lymph nodes removed at necropsy from females killed in traffic accidents showed no predominance of either B- or T-cell stimulation.