Immunologic monitoring for rejection diagnosis during the first three months after heart transplantation

Objective: Determination of lymphocyte subset alterations during the early phase after heart transplantation. Comparison of lymphocyte activation para meters and concentrations of soluble class I MHC molecules with the establi shed endomyocardial biopsy rejection grading results. Patients and Methods: 154 heart transplant patients with 382 endomyocardial biopsies during the first 3 months after transplantation. The following statistical data were c alculated: sensitivity, specificity, positive predictive value, negative pr edictive value, and diagnostic efficiency (sum of true-positive and true-ne gative results as a part of total results). The immunophenotyping by flow c ytometry includes CD4+, CD8+, CD3/HLA-DR+, CD8/HLA-DR+ and CD4/CD25+ subset s. The activation index (activated lymphocytes defined by microscopy after staining) was also determined. Results: By shifting the cutoff of lymphocyt e subsets to higher cell concentrations, the positive predictive values inc reased, reaching 60-100% for some parameters. However, the overall diagnost ic efficiency was considerably lower: activation index 54%, CD8/HLA-DR+ 58% , CD3/HLA-DR+ 57%, CD4/CD25+ 49%, and CD4/CD8-ratio 46%. The determination of soluble class I MHC molecules in plasma samples drawn during rejection e pisodes and in rejection-free periods in a group of 53 heart transplant pat ients showed no differences between the periods. Conclusions: Immunophenotyping by flow cytometry or cytology for detection of activated T lymphocytes in peripheral blood has a low overall diagnostic efficiency in rejection diagnosis. The determination of soluble class I MH C molecules seems to be of no value for the early detection of rejection.