¡¾Abstract¡¿ AIM: To study the clinical value of responsive acidophil in peripheral blood for diagnosing acute graft rejection following organ transplant. METHODS: Sixtyª²three patients were divided into two groups, acute graft rejection group (24 patients) and nonª²rejection group (39 patients), and 40 donors were in the normal control group. All blood preparations were stained by Wright¬ðs method and examined by microscope. RESULTS: Responsive acidophil was found in all acute graft rejection patients [(12.2¡À2.3)%], and its positivity was 100%, while responsive acidophil was found in only 2 patients (x=1.6%) in nonª²rejection group (39 patients) and its positivity and specificity were 5.1% and 94.9%, respectively. No responsive acidophil was found in normal control group. The eosinophil rate was (4.1¡À1.4)%in the rejection group, (3.9¡À1.6)% in the nonª²rejection group and (4.3¡À1.9)% in control group, with no significant difference between the three groups (P>0.05). CONCLUSION: The responsive acidophil in peripheral blood can be used as a predictor in diagnosing acute graft rejection following organ transplant. ......