The prognostic value of the eosinophil in acute renal allograft rejection.

A case report of marked peripheral blood eosinophilia and eosinophilic infiltration of a rejected renal allograft in a transplant recipient stimulated our review of the clinical course of 132 consecutive renal transplant recipients. A total of 187 acute rejections occurred in 112 patients. Diagnosis was made by renal biopsy in 124 cases. The percentage of eosinophils in the leukocyte differential of patients with irreversible rejection was 5.2 +/- 5.7 (mean +/- SD) versus that seen in patients with reversible rejection, 2.9 +/- 3.5 (P less than .05). The difference in the total eosinophil counts in each group was not statistically significant. Patients with peripheral blood eosinophil percentages greater than or equal to 4% had a 37.9% irreversible rejection rate, whereas those who had less than 4%, had a 22.4% loss rate (P less than .01). Six of seven patients with greater than or equal to 2% eosinophils in the inflammatory infiltrate of their renal allograft lost their kidney, whereas grafts with less than 2% eosinophils had a 36.8% loss rate (P less than .02). We conclude that the increased presence of eosinophils in the peripheral blood and/or renal allograft biopsy specimen is an adverse prognostic factor for acute rejection outcome.