PRE AND POSTOPERATIVE IMMUNITY IN AGED CANCER PATIENTS -WITH SPECIAL REFERENCE TO THE POSTOPERATIVE MEHCILLIN-CEFEM RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) INFECTION AND CELL-MEDIATED IMMUNITY-

A prospective study to examine the relationship of pre- and postoperative cellular immune responses to the postoperative MRSA infection has been conducted in the aged patients with malignant tumors. Subjects were 12 patients with stomach cancer and 9 with the colon cancer, with a men age of 76.7 years. In these 21 patients, the activities of peripheral blood T lymphocyte subsets (CD4, CD8, CD4+2H4-., CD4+2H4-) and NK cells were measured. MRSA infection occurred as a postoperative complication in 4 patients, who all had an advanced cancer. Cases complicated by infection were compared with those not complicated by infection for the cellular immune responses. The results were: 1) There was no significant difference between both groups in CD4, CD8, and CD4/CD8. 2) Preoperative helper T cell (CD4+2H4-) ratio was significantly reduced in cases complicated by MRSA infection. 3) Suppressor-inducer T cell (CD4+2H4-) ratio was significantly elevated in advanced cancers. 4) The restoration of NK cell activity was significantly delayed in cases complicated by MRSA infection. These results suggest that the postoperative development of MRSA infection in aged patients depends partly on the host immunological competence.