Association between blood eosinophil counts and acute cardiac and pulmonary allograft rejection

Peripheral blood eosinophilia is a particularly early and specific marker of both renal and hepatic allograft rejection. Therefore we evaluated the relationship between blood eosinophil counts and cardiac and pulmonary allograft rejection.

Differential blood counts were available within 3 days before 383 endomyocardial biopsy specimens in 56 heart transplant recipients. Blood counts were also available before 84 treated rejection episodes and 28 transbronchial biopsy specimens showing no rejection in 58 lung transplant recipients.

Cardiac allograft rejection: There was a significant association between the mean maximum blood eosinophil count and treated acute rejection (p < 0.01) and a linear relationship between this eosinophil count and the histologic grade of rejection (p < 0.01). The first increase in eosinophils occurred at a median of 4 days before treated rejection. Pulmonary allograft rejection: The mean maximum blood eosinophil count was 0.14 x 10(9)/L (95% confidence interval = 0.10, 0.18) preceding treated rejection, and this was significantly greater than the mean maximum blood eosinophil count of 0.07 x 10(9)/L (confidence interval = 0.05, 0.09) measured when there was no rejection or during infection (p = 0.01). The first increase in eosinophil occurred at a median of 5 days before treated rejection. There was no relationship between blood neutrophil counts and either cardiac or pulmonary allograft rejection.

An increase in peripheral blood eosinophils but not neutrophils is a specific and early marker of clinically significant rejection of both cardiac and pulmonary allografts. Furthermore, the maximum blood eosinophil count measured in the 3 days before rejection is linearly related to the severity of cardiac allograft rejection.