B lymphocyte response as an indicator of acute renal transplant rejection. I. Immunoglobulin-secreting cells in peripheral blood.

Monitoring of immunoglobulin-secreting cells in peripheral blood was performed in 88 renal transplant recipients using a reverse hemolytic plaque-forming cell assay. Comparison with other in vitro tests for rejection (plasma neopterin, CD4/CD8 ratio) demonstrated that the number of immunoglobulin-secreting cells in peripheral blood provides a highly sensitive rejection marker. Evidence of rejection was obtained 1.7 +/- 0.4 (mean +/- SEM) days before a rise in creatinine, with a significant PFC rise in 95% (73/77) of rejection episodes. The PFC response was not influenced by HLA matching, number of preoperative blood transfusions, acute tubular necrosis, or uremia. A significant PFC rise in the absence of an ongoing rejection episode occurred in the presence of bacterial or viral infections, in case of posttransplant surgical complications, and regularly during the early posttransplant period (days 4-9). However, even early posttransplant the PFC peak was significantly higher in patients with an ongoing rejection episode than in patients without rejection (P less than 0.001).