Comparison of whole-blood cyclosporine levels and the frequency of endomyocardial lymphocytic infiltrates (the Quilty lesion) in cardiac transplantation.

Endomyocardial lymphocytic infiltrates (ELI), or "Quilty" lesions are morphologically and immunohistochemically distinct and are thought to be due in part to Cyclosporine therapy. In order to evaluate the relationship of ELI to CsA therapy, we compared the whole-blood CsA levels (WBCsA) with the frequency of ELI in our cardiac transplant patients. From January 1, 1987 to January 1, 1988, 364 concurrent endomyocardial biopsies and WBCsA were performed on 43 cardiac transplant patients. All biopsies were evaluated for acute rejection. ELI were recognized as well-circumscribed, flat or pedunculated lesions within the endomyocardium composed of mature T lymphocytes with pockets of B lymphocytes and occasional macrophages and plasma cells. All WBCsA were trough levels and were determined by high-pressure liquid chromatography. Results were evaluated using a logistic regression model for clustered data. ELI were observed in 17.9% (65/364) biopsies, and 60.5% (26/43) of patients had at least one ELI during the study period. The mean WBCsA was 155.2 ng/ml (SD = 62.9) in the ELI-positive group, and 190.2 ng/ml (SD = 97.0) in the ELI-negative group. Applying the regression model revealed a statistically significant negative correlation between WBCsA and the presence of ELI (P = 0.033)--that is, a lower WBCsA was associated with an increased probability of ELI. The frequency of clinically significant rejection was lower in the ELI-positive biopsies, and this correlation approached statistical significant (P = 0.053). These data suggest that ELI are unrelated to increased WBCsA and may represent an idiosyncratic reaction to CsA, or be related to factors other than CsA therapy.