Quilty effect correlates with biopsy-proven acute cellular rejection but does not predict transplanted heart coronary artery vasculopathy.

Background: The appropriate therapy after orthotopic heart transplantation (OHT) is determined by the results of endomyocardial biopsies (EMBs). The Quilty effect (QE) is a recognized cause of discrepancies in EMB grading, but its clinical implications remain unclear. In this study we assess the correlation of the QE with biopsy-proven acute cellular rejection (AR) and coronary artery vasculopathy (CAV).
Methods: We reassessed 5,361 EMB samples, obtained from 429 patients, based on QE occurrence and its impact on EMB score. Next, we divided all patients with at least 1 year of follow-up into two groups: a QE(+) group (n = 202, 58.7% of sample, 172 males/30 females, 44.8 +/- 12 years of age) and a QE(-) group (n = 142, 41.3% of sample, 124 males/18 females, 45.4 +/- 12 years of age), and compared AR and CAV occurrences.
Results: The QE was observed in 669 EMBs (12.5%), and at least 1 EMB with QE was found among the 231 patients (53.8%). The initial QE occurrence took place during the first 3 months after OHT in 68% of QE(+) patients, and >1 year post-OHT in 13% of patients. The average EMB score was significantly higher in QE(+) biopsies. A comparison of the two groups revealed a significantly higher number of AR episodes and number of patients with at least one episode of AR in QE(+) patients. There was no significant difference in number of CAV occurrences between groups.
Conclusions: The QE seems to be a marker of the same increased immune system activity that can lead to AR. A relationship between QE and CAV was not supported by the present results.