Depression of high-affinity rosette formation in dysplasia and carcinoma in situ of the uterine cervix: mediation by serum factors.

High-affinity erythrocyte rosettes (HA-RFC) have been shown previously to be depressed in patients with dysplasia and carcinoma in situ of the uterine cervix. The effect of serum from these patients on HA-RFC in normal lymphocytes was studied to further elucidate the nature of immunological changes in early cancer. Sera from patients with dysplasia and carcinoma in situ significantly decreased HA-RFC in normal lymphocytes as compared to control serum (p less than 0.001). Serum inhibitory activity correlated well (p less than 0.001) with HA-RFC in the patients' lymphocytes and was postulated to represent the presence of a serum factor in these patients. Liquid chromatography studies showed this factor to have a molecular weight of approximately 50,000. Additional factors with molecular weights of 73,000 and 88,000 were present in patients with carcinoma in situ but not in patients with dysplasia. Serum inhibitory activity was not observed in Stage I squamous cell carcinoma. These factors may represent antigen-specific suppressor factors produced in response to the expression of neoantigens by premalignant cells and may be involved in "sneaking through" of developing tumors.