Quantification of serum-soluble HLA class I antigens in patients with gastric cancer.

The amount of sHLA-I in serum was examined in 74 patients with gastric cancer and 15 normal healthy controls. For mAbs, W6/32 specific for HLA-A, -B, -C, and biotin IOT2 specific for HLA class I associated with beta 2 microglobulin, were used to determine the values of sHLA-I using an ELISA. The patients in stage-IV gastric cancer showed lower values of sHLA-I (445.4 +/- 247.1 ng/ml) than those in stage I (725.9 +/- 575.8 ng/ml), stage II (752.8 +/- 255.0 ng/ml), and normal controls (868.9 +/- 715.0 ng/ml) (P < 0.05). In analysis of the patients with HLA-A24, the allele that has been reported to secrete more sHLA-I than other alleles, the results were nearly the same. These results suggest that the secretion of sHLA-I is low in patients with very advanced cancer. However, there was no correlation between the sHLA-I level and the metastasis or prognosis in longitudinal studies in 11 patients.