One or more of the following moAb, with their corresponding HLA molecular specificity, were selected: SG157 (anti-DR) and SG465 (broad anti-class II) (S

One or more of the following moAb, with their corresponding HLA molecular specificity, were selected: SG157 (anti-DR) and SG465 (broad anti-class II) (S. pyruvate transaminase (SGPT), although a pattern towards higher values was noted for biopsies presenting Doxercalciferol with a class Doxercalciferol II specific infiltrate. However, the levels of gamma glutamyl transpeptidase (GGTP) and alkaline phosphatase (AP) were significantly increased when biopsies yielded class II specific rather than class I specific PLT cells. Biopsy histology showed more damage to bile duct epithelium in association with class II PLT specificity whereas intense but often reversible infiltrates were found in biopsies yielding class I specific cells. The elevated GGTP and AP levels are probably related to the conversation of class II specific T cells with bile duct epithelium, which has been shown to express induced class II HLA antigens on their cell surface. strong class=”kwd-title” Keywords: T-lymphocytes, liver transplants, donor HLA alloreactivity, liver function assessments, histopathology, bile duct damage INTRODUCTION While liver transplantation has become an accepted form of treatment for a variety of endstage liver diseases, the understanding of the immunobiology of liver transplant rejection is still incomplete. Various findings suggest that the immunologic course of liver transplants differs substantially from that of other solid organ Fzd10 transplants (1C8). T-lymphocytes are known to play a major role in cell mediated allograft rejection (9C10). In cellular infiltrates of transplants it is possible to demonstrate activated T cells expressing Interleukin-2 (IL-2) receptors on their cell surface. These cells are capable of undergoing further proliferation upon exposure to IL-2 (11C12). Previous studies have shown that activated T-cells can be propagated in vitro from liver allograft biopsies in the presence of exogenous recombinant IL-2 (13, 14). Further analysis of these biopsy produced lymphocytes has revealed the presence of alloreactive T-cells specific for donor HLA antigens. Often enough, these cell cultures exhibit restricted specificity patterns against one or few of the donor HLA antigens. This alloreactivity could also be blocked with monoclonal antibodies (moAb) against appropriate HLA determinants. Comparable observations have been made with lymphocyte cultures produced from heart transplant biopsies (15). In certain patients, there appeared a sequential infiltration of the allograft by class I specific lymphocytes in earlier biopsies followed by class II or mixed class I/II specific lymphocytes in later biopsies (16). The aim of this study was to evaluate the association of the HLA class I and class II allospecificity of lymphocytes produced from liver allograft biopsies with clinical, biochemical and histopathologic findings. MATERIALS AND METHODS All liver transplant recipients received cyclosporine and steroids as immunosuppressive drugs. As of December 1984 OKT3 monoclonal antibody therapy has been added to treat acute rejection episodes. Samples of hepatic allografts were obtained from percutaneous liver biopsies or removed allografts. Indications for sampling were derangements in liver function tests and bile composition. It is important to emphasize, that all biopsies were obtained when problems occurred and that these were no protocol biopsies. All samples were taken in a sterile manner for propagation of infiltrating cells and histologic evaluation. No attempt for HLA matching of liver transplants was made, because of the very limited time available for all the events related to the harvesting and transplant procedure. Liver biopsies were divided into smaller segments and cultured in microculture wells with 100 ul of recombinant IL-2 and 100 ul of Doxercalciferol tissue culture medium as described previously (13). The cultures were observed daily on an inverted stage microscope and supplemented with IL-2 at 2C3 day intervals. After approximately 2 weeks, sufficient cells (0.5C1.0106) were obtained for primed lymphocyte testing (PLT) assays. The cultured lymphocytes were tested against cryopreserved donor splenocytes, exogenous IL-2 and an informative panel of unrelated lymphocytes with known HLA type. In blocking studies different anti-class I and anti-class II moAb were tested for their inhibitory effect on the PLT response of these cultured T cells. One or more of the following moAb, with their corresponding HLA molecular specificity, were selected: SG157 (anti-DR) and SG465 (broad anti-class II) (S. Goyert and J. Silver [17]); L243 (anti-DR) and Leu 10 (anti-DQw1 + w3) (Becton Dickinson, Mountain View, CA [18C20]); PA2.6 (anti-HLA-A, B, C) (P. Parham[21, 22]); or w6/32 (anti HLA – A, B, C) (Pel-Freez, Rogers Arkansas [23C24])..