Morphometric image analysis and eosinophil counts in human liver allografts

Abstract

Histology of liver allografts is the gold standard for diagnosis of acute cellular rejection. However, scoring the severity of rejection and distinguishing it from other infiltrations is not easy. Only one group has evaluated biopsies morphometrically and also suggested that eosinophils are a specific diagnostic feature. We quantitated eosinophil count in 92 biopsies in a group of 25 patients and, in another group of 30 patients, used morphometric image analysis to measure the cross‐sectional area and cell density in each portal tract in day 5 protocol liver biopsies. Rejection was diagnosed by pathological evaluation confirmed with clinical and biochemical graft dysfunction graded histologically into mild or moderate‐to‐severe. The control groups were five patients with no rejection, nine patients with CMV infection, and eight biopsies in eight patients for whom the cause of the liver dysfunction was obscure. The cross‐sectional area, the inflammatory cell count of each portal tract and the mean portal tract inflammatory cell density (cells/mm2) increased with the severity of rejection. In each case the regression coefficient was statistically signifinant. Correlating the mean of the total inflammatory cell count with the mean of the portal inflammatory cell density (cell/mm2) gave far better separation of the mild rejection and moderate‐to‐severe rejection groups. Eosinophils were specific for the presence of acute cellular rejection and increased with the severity of rejection. They were absent in the no rejection group, in the CMV group and in those with obscure liver dysfunction. The eosinophil count fell markedly following treatment of rejection. We conclude that morphometric image analysis can be used to quantify acute cellular rejection and that eosinophils are a specific feature of acute cellular rejection.