Immunohistochemical Quantification of Inflammatory Cells in Endomyocardial Biopsy Fragments After Heart Transplantation: A New Potential Method to Improve the Diagnosis of Rejection After Heart Transplantation

Inconsistencies in cardiac rejection grading systems corroborate the concept that the evaluation of inflammatory intensity and myocyte damage seems to be subjective. We studied in 36 patients the potential role of the immunohistochemical (IHC) counting of inflammatory cells in endomyocardial biopsy (EMB) as an objective tool, testing the hypothesis of correlation between the International Society for Heart and Lung Transplantation 2004 rejection and IHC counting of inflammatory cells. We observed a progressive increment in CD68+ cells/mm2 (P = .000) and CD3+ cells/mm2 (P = .000) with higher rejection grade. A strong correlation between the grade of cellular rejection and both CD68+ cells/mm2 and CD3+ cells/mm2 was obtained (P = .000). One patient with CD3+ and CD68+ cells/mm2 above the upper limit of the 95% confidence interval for cells/mm2 found in rejection grade 1R evolved to rejection grade 2R without treatment. In patients with 2R that did not respond to treatment the values of CD68+ or CD3+ cells were higher than the overall median values for rejection grade 2R. For diagnosis of rejection needing treatment, the CD68+ and CD3+ cells/mm2 areas under the receiver operating characteristic curves were 0.956 and 0.934, respectively. IHC counting of mononuclear inflammatory infiltrate in EMB seems to have additive potential role in evaluation of EMB for the diagnosis and prognosis of rejection episodes.