腎癌における腫瘍免疫の研究 --白血球粘着阻止試験の意義--

Abstract

30例の腎癌症例および43例の対照群に対して白血球粘着阻止試験を施行した.1)正常対照のNon-Adherence Index (NAI)値は-19～36の間に分布し, その平均は7.0で, 本検査の陽性境界値を40と定めた.2)腎癌患者群は対照群に比べLAI陽性率は有意に高く, 腎癌に共通な癌関連抗原の存在が示唆された.3)腎癌のlow stage群とhigh stage群との間には, LAIの反応性にとくに差は認められなかった.4)主病巣摘出1～2週間後には, 検索した9症例すべてのNAI値が低下していた.5)術後5～6ヵ月後において臨床上再発を認めない3症例では, LAI陰性であったが, 術後5ヵ月で骨転移を有していた症例ではLAI陽性であった

The adherence to glass of peripheral blood leukocytes (PBL) incubated with antigen in vitro is specifically inhibited if the PBL are sensitized to the antigen. The presence of leukocyte adherence inhibition (LAI) in a tumor extract indicated the presence of antitumor immunity. Tube LAI assay was performed using renal cancer extract as a specific antigen and bladder cancer extract as a non-specific antigen on patients with renal cancer, malignant renal disease other than renal cell carcinoma, benign renal disease, cancer of organs other than the kidney and in healthy donors. The optimal tumor extract protein concentration was established for the renal tumor extract and control extract by determining the dilution of tumor extract that produced the most specific and the least non-specific inhibition of leukocyte adherence. In this study, the renal cancer extract and control extract were used at 1.0 mg/ml protein concentration. An NAI value greater than 40 was considered a positive reaction, because more than 90% of the control population had values below 40 and more than 85% of the patients with renal cancer had values above 40. PBL from 26 of the 30 patients (87%) with renal cancer responded to extracts of renal cancer, whereas only 1 of the 8 patients (13%) with malignant renal disease other than renal cell carcinoma, 1 of the 10 patients (10%) with benign renal disease and 1 of the 17 patients (6%) with cancer of organs other than the kidney showed a response. None of 6 healthy donors showed a response. There is no remarkable difference of NAI value between low and high renal cancer. Surgery depressed LAI reactivity. The NAI was negative after 5-6 months post operatively in 3 tumor-free patients who had positive LAI reactivity before surgery. Patients with residual tumors showed persistent LAI reactivity after 5 months post operatively. Further study on the tube LAI assay is recommended because it may be valuable in the differential diagnosis of renal cancer and in monitoring the post operative course.