Intragraft events after heart transplantation: an experimental study comparing cytology in coronary sinus blood, peripheral blood, and daily histology.

ABSTRACT

Acute rejection is a frequent consequence after heart transplantation. To expand our knowledge of the rejection process and to investigate some intragraft events during acute rejection, the following experimental transplantation model was designed. Right cervical heart transplantation was performed in 12 mongrel dogs. Two experimental groups of six animals each received different immunosuppressive regimens. All animals were treated with daily triple drug therapy. In contrast to group 1, the animals in group 2 received high-dose steroids during rejection. The condition of the hearts was examined by daily transmural biopsies, graded according to the Billingham classification. To detect and quantify alterations in the mononuclear cell subsets of the myocardial venous return, blood samples from the coronary sinus blood (CS) and from peripheral blood (PB) were taken simultaneously with the biopsy. The total number of lymphoblasts and activated lymphocytes was determined and an activation index (AI) was calculated. The data referred to was established from 337 transmural biopsies. The AI of PB (n = 287) correlated well with the different stages of acute rejection (grade B0 AI = 2.2 +/- 2.1; grade B1 + 2 AI = 6.3 +/- 1.7; grade B3 AI = 10.0 +/- 4.7; P < 0.001). The rejection kinetics of both groups, including the rejection-free interval following high-dose steroid administration in group 2, could be expressed accurately by the AI. The time course of the total number of lymphoblasts in CS versus PB demonstrated that the lymphoproliferative response started 4 days prior to the first intramyocardial signs of rejection (mean = 3.8 +/- 0.7; n = 12).(ABSTRACT TRUNCATED AT 250 WORDS)