INVERTED V-DELTA-1 V-DELTA-2 RATIO WITHIN THE T-CELL RECEPTOR (TCR)-GAMMA-DELTA T-CELL POPULATION IN PERIPHERAL-BLOOD OF HEART-TRANSPLANT RECIPIENTS/

We investigated the levels of TCR-gamma delta T cells and their subpop ulations V delta 1 and V delta 2 in the peripheral blood lymphocytes ( PBL) of 28 heart transplant (HTx) patients. Patients (n = 10) receivin g cyclosporin A (CsA) for treatment of a nephrotic syndrome (NS) and 1 0 healthy individuals served as controls. There was no difference in l evels of TCR-gamma delta T cells between the different groups. However , an elevated proportion of V delta 1(+) gamma delta T cells was found in the PBL of HTx patients, especially when these cells were present in their graft-infiltrating lymphocyte (GIL) cultures. V delta 1(+) ga mma delta T cells of HTx patients showed normal expression of CD45RO a nd lacked the activation markers CD25 and HLA-DR. After expanding in I L-2-containing medium, PBL cultures of HTx patients more often were do minated by V delta 1 cells than PBL cultures of controls, in which V d elta 2 cells were predominantly grown. The aberrant composition of the TCR-gamma delta population in HTx patients was not a result of immuno suppressive medication, since the proportion V delta 1(+) gamma delta T cells was normal in the PBL of the NS patients receiving a similar d ose of CsA. It is postulated that long-term antigenic stimulation by t he graft, at low level, might be responsible for the altered compositi on of the gamma delta pool in the HTx patients. Since no donor HLA-spe cific gamma delta T cells have been detected, other ligands, such as h eat shock proteins, may be involved.