Search PubMed⌕ Search

Biomedical subjects

R J Duquesnoy

Publications and source records attributed to R J Duquesnoy.

At least 19 recordsLinked to original sources
PubMed1995

Heat shock protein reactivity of lymphocytes isolated from heterotopic rat cardiac allografts.

Although it is well known that cellular rejection is mediated by alloreactive lymphocytes, several investigators, including our group, have shown that such cells are a rather small proportion of the T cell infiltrate of the alolograft. We have therefore postulated that graft-infiltrating lymphocytes must recognize other antigens. Since heat shock protein (hsp)-specific lymphocytes have been shown to participate in several autoimmune diseases and in tumor immunity, we hypothesized that hsp-reactive lymphocytes are involved with allograft rejection. This hypothesis was tested with a rat model of heterotopic MHC-incompatible cardiac allografts (ACI into Lewis), whereby graft-infiltrating lymphocytes and spleen cells were tested in vitro with different recombinant mycobacterial hsp preparations. As expected, allograft lymphocytes showed proliferative responses to irradiated spleen cells from the donor. This proliferation was markedly augmented by hsp65 (3-fold) and hsp70 (5-fold), whereas hsp10 and the protein control ovalbumin had no effect. Proliferation of allograft lymphocytes to hsp in context with syngeneic splenocytes as antigen-presenting cells (APC) was seen primarily if small quantities of IL-2 had been added to the cultures. In contrast, hsp-specific proliferation was never observed with syngraft lymphocytes, even after addition of IL-2. Spleen cells from allograft and syngraft recipients showed hsp augmentation of alloproliferation, but the magnitude was less than that with allograft lymphocytes. Kinetic studies showed that hsp-reactive lymphocytes first appeared in the allograft on day 3 posttransplant. Tacrolimus immunosuppression of transplant rejection prevented the appearance of hsp-reactive lymphocytes in allografts. Culture conditions have been established to generate hsp65- and hsp70-specific T lymphocyte lines and clones from allograft-infiltrating cells. These cultured cells exhibited hsp reactivity only in context with self-APC, and this was augmented by small amounts of IL-2. These data provide strong evidence for the involvement of hsp-reactive lymphocytes in allograft rejection. We propose the concept that during rejection tissue stress induced by alloreactive effector lymphocytes promotes the recruitment and activation of hsp-reactive lymphocytes, especially in the presence of IL-2 released into the allogeneic environment of the transplant. These hsp-reactive T cells may play a role in the immune cascade of the inflammatory process of transplant rejection.

Animals↗
PubMed1995

Cytokine mRNA profiles in mouse orthotopic liver transplantation. Graft rejection is associated with augmented TH1 function.

Although mouse liver allografts are spontaneously accepted without immunosuppression in many strain combinations, rejection can be induced by presensitization with a donor skin graft two weeks prior to transplantation. In this study, the semiquantitative reverse transcription polymerase chain reaction (RTPCR) was used to assess the involvement of T helper (TH) cell subsets in liver allograft acceptance by determining cytokine mRNA in the graft and spleen of recipients with (A) spontaneously accepting allografts (B) rejecting liver allografts after previous skin sensitization, and (C) syngeneic controls. Spontaneously accepted liver allografts showed upregulation of TH1 (IL-2, IFN-gamma) and TH2 (IL-4, IL-10) intragraft cytokine mRNA, which peaked at day 6 and tapered off thereafter, when compared with levels in syngeneic grafts, but both IFN-gamma and IL-10 mRNA persisted up to day 30. This cytokine mRNA profile correlated with the transient intragraft inflammation associated with spontaneously resolving rejection. Presensitized recipients that rejected their grafts revealed marked upregulation of TH1 (IL-2 and IFN-gamma) and TH2 (IL-4, IL-6) intragraft cytokine mRNAs compared with spontaneously accepting recipients, although IL-10 mRNA levels showed no differences between the two groups. The most striking difference was seen in IFN-gamma levels, which correlated well with the preferential deposition of IgG2a antibody isotype in the rejecting compared with the spontaneously accepting liver allograft recipients. These results suggested an association between liver allograft rejection and enhanced TH1 cytokine immune response. The ability to reject liver allografts by the adoptive transfer of splenocytes, but not serum, from a sensitized mouse ruled out preformed antibodies alone as a cause of rejection. However, spleen cytokine mRNA profiles showed no differences or trends in TH1 or TH2 expression in spontaneously accepting versus rejecting recipients, which suggested that the spleen is not a major site of alloreactive immune expansion. These data suggest that spontaneous acceptance of mouse liver allografts is associated with an insufficient intragraft TH1 cytokine response, the cause of which is currently under investigation.

Animals↗
PubMed1995

Immunoglobulin G lymphocytotoxic antibodies in clinical liver transplantation: studies toward further defining their significance.

Twenty-two consecutive liver allograft recipients, who tested positive for immunoglobulin G (IgG) lymphocytotoxicity were subjected to pretransplantation and posttransplantation immunologic monitoring of anti-donor IgG lymphocytotoxic antibody titers, total hemolytic complement activity (CH100), circulating immune complexes (CIC), and platelet counts in an effort to improve our understanding of the preformed antibody state in clinical hepatic transplantation. Ten contemporaneous liver transplant recipients whose crossmatch results were negative and who experienced severe hepatocellular damage early after transplantation were included as controls. Crossmatch test results were negative 1 day after transplantation and during the 1 month follow-up remained negative in 14 of 22 (64%) sensitized recipients, most of whom had relatively low (< or = 1:16) anti-donor IgG antibody titers before transplantation. After transplantation, this group and the control group experienced no thrombocytopenia, no increase of CIC, and a gradual increase in CH100 activity that reached normal levels within 1 week. A strong negative correlation between prothrombin time (PT) and CH100 activity in these groups of patients suggested that changes in CH100 activity (P < .0005) were tightly linked to liver synthetic function. In contrast, the crossmatch test results remained positive after transplantation in 8 of 22 (36%) sensitized recipients, all of whom had relatively high (> 1:32 to 1024) pretransplantation titers of anti-donor IgG antibodies. After transplantation these patients developed a syndrome that was characterized by decreased CH100 activity and increased CIC compared with pretransplantation levels and refractory thrombocytopenia that was associated with a 50% allograft failure rate because of biopsy-proven humoral and acute (cellular) rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Expression of stress proteins and lymphocyte reactivity in heterotopic cardiac allografts undergoing cellular rejection.

This report addresses the concept that, during rejection, the allograft undergoes a stress response which leads to an increased expression of stress proteins, also called heat shock proteins (hsp), and the recruitment and activation of hsp-reactive lymphocytes. Recent studies in our laboratory have provided evidence that hsp-reactive T-cells are present in cardiac allografts undergoing rejection. In this study, an MHC incompatible heterotopic heart allograft model (ACI into LEW) was chosen to analyse the kinetics of hsp expression during the development of rejection. Allografts and syngrafts (LEW into LEW) were harvested every day during the first 5 days post-transplant. Immunoblot analysis of proteins extracted from graft stromal tissues was done with murine monoclonal antibodies (mAb) against various mammalian hsp. Proliferation studies were done to determine hsp reactivity of graft-infiltrating lymphocytes on different days post-transplant. Three types of stressful stimuli appeared to increase hsp expression in the allograft. The first was a physiological stress secondary to the trauma of the transplant procedure and ischaemia/reperfusion injury and this would occur in allogeneic and syngeneic grafts. During the first day after transplantation, both types of grafts showed higher expression of hsp72 and grp78 and to a lesser extent, hsp60 and grp75. On the second and third day, the expression of grp78 and grp96 was higher in allografts than in syngrafts and this may reflect an immunologically mediated stress response in the allograft when infiltrating hsp-reactive lymphocytes became first detectable in the allograft. The third type of stress appeared related to the inflammatory process associated with rejection. On the fourth and fifth day post-transplant, the allografts showed strong expression of at least five proteins of lower molecular mass reacting with hsp-specific mAbs; namely, approximately 40 kDa (detected by anti-hsp60), approximately 30 kDa (by anti-hsp72), approximately 45 kDa and approximately 32 kDa (by anti-hsp72 + hsc73), and approximately 50 kDa (by anti-grp78). At that time, the allograft began to show progressive inflammatory changes and tissue damage. The appearance of lower molecular mass hsp-crossreactive proteins might reflect a degradation of hsps which had increased expression earlier during the post-transplant period. This process may generate large quantities of hsp-derived peptides which may be presented by MHC molecules to graft-infiltrating T-cells. Another interpretation of the strong expression of lower molecular bands in later allografts is that they represent other stress proteins that crossreact with antibodies against hsp60 and hsp70 family members.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1995

Obliterative bronchiolitis after lung and heart-lung transplantation. An analysis of risk factors and management.

With a prevalence of 34% (55/162 at-risk recipients) and a mortality of 25% (14/55 affected recipients), obliterative bronchiolitis is the most significant long-term complication after pulmonary transplantation. Because of its importance, we examined donor-recipient characteristics and antecedent clinical events to identify factors associated with development of obliterative bronchiolitis, which might be eliminated or modified to decrease its prevalence. We also compared treatment outcome between recipients whose diagnosis was made early by surveillance transbronchial lung biopsy before symptoms or decline in pulmonary function were present versus recipients whose diagnosis was made later when symptoms or declines in pulmonary function were present. Postoperative airway ischemia, an episode of moderate or severe acute rejection (grade III/IV), three or more episodes of histologic grade II (or greater) acute rejection, and cytomegalovirus disease were risk factors for development of obliterative bronchiolitis. Recipients with obliterative bronchiolitis detected in the preclinical stage were significantly more likely to be in remission than recipients who had clinical disease at the time of diagnosis: 81% (13/15) versus 33% (13/40); p < 0.05). These results indicate that acute rejection is the most significant risk factor for development of obliterative bronchiolitis and that obliterative bronchiolitis responds to treatment with augmented immunosuppression when it is detected early by surveillance transbronchial biopsy.

Adolescent↗
PubMed1995

Immunopathology of cardiac transplant rejection.

Transplant rejection represents a diverse series of complex immunological events beginning with allorecognition and lymphocyte activation and differentiation, followed by interactions of antibodies and activated lymphocytes with the vascular endothelium and subsequent cellular infiltration into the allograft, and, finally, the inflammatory process leading to tissue injury. This paper reviews how these events contribute to the different types of cardiac transplant rejection, including cardiac allograft vasculopathy.

Cell Adhesion Molecules↗
PubMed1995

Phenotypic and functional characteristics of colonic lymphocytes isolated from patients with primary sclerosing cholangitis and inflammatory bowel disease.

Because primary sclerosing cholangitis (PSC) frequently is associated with inflammatory bowel disease, the phenotypic and functional characteristics of lymphocytes isolated from colonic mucosa were studied in patients with primary sclerosing cholangitis (PSC), patients with ulcerative colitis and patients with other colonic and hepatic disorders. To accomplish this, lymphocytes isolated from colonic biopsies obtained at the time of colonoscopy were expanded in vitro in the presence of interleukin 2 (IL2). Cell propagation was similar in patients with PSC with or without associated inflammatory bowel disease but was diminished significantly when compared to results obtained in patients with ulcerative colitis not associated with PSC. The CD4:CD8 ratio of the propagated lymphocytes was increased in patients with PSC compared to controls. The Leu 19+ subset of cells was also increased in PSC patients. In patients with inflammatory bowel disease, increased cytotoxicity was noted at low effector to target cell ratios with SK-HEP (hepatocellular carcinoma) but not RPMI 7451 (cholangiocarcinoma) targets. No differences between PSC patients and controls were observed for NK sensitive and NK resistant targets. Based upon these studies it can be concluded that: 1) expansion of lymphocytes obtained from endoscopic colonic biopsies using recombinant IL2 represents an alternative method by which intestinal lymphocytes can be studied; 2) natural killer cells are increased in the colonic mucosa of patients with primary sclerosing cholangitis; 3) colonic cytotoxic T lymphocytes may be more active in patients with chronic liver disease and particularly those with associated inflammatory bowel disease.

Adult↗
PubMed1994

Progress report on the ASHI/CAP Proficiency Survey Program in Histocompatibility Testing. I. HLA-A,B,C typing, antibody screening, and lymphocytotoxicity crossmatching. American Society for Histocompatibility and Immunogenetics. College of American Pathologists.

The Histocompatibility Survey Program was organized in 1982 as a joint project by the ASHI and CAP to evaluate laboratory performance in HLA typing, lymphocytotoxicity crossmatching, and antibody analysis. This report summarizes the experience with the HS surveys on HLA class I serology. During a 12-year period, the number of participating laboratories increased from 150 to 285 and HLA typing was done with 90 survey specimens representing 20 HLA-A and 35 HLA-B antigens. Most unsplit antigens were correctly identified in more than 90% of the laboratories. For many antigens, a high percentage of participants reported a split and there was generally a high consensus of a correct assignment. Nevertheless, several antigens were difficult to define, as shown by low consensus rates. During recent years, the assignments of Bw4/6 and HLA-C antigens have significantly improved. Lymphocytotoxicity crossmatching was analyzed for 138 cell-serum combinations tested by an average of 143 laboratories. Comparisons between four techniques (basic NIH, Amos modified, LI, and AHG) showed consistent results (greater than 90% crossmatch compatibility or incompatibility) for 71% of the cell-serum combinations. The crossmatch results with the remaining combinations were more variable for one or more of the crossmatch techniques. Serum antibody identification showed a continued improvement during recent years, and the average consensus for assigning acceptable antibody specificity reached 88%. A performance grading system based on a 90% consensus rate among participants is used to satisfy requirements for laboratory accreditation.

Cytotoxicity Tests, Immunologic↗
PubMed1994

Progress report on the ASHI/CAP Proficiency Survey Program in Histocompatibility Testing. II. HLA-DR, DQ serologic typing, antibody identification, and B-cell crossmatching. American Society for Histocompatibility of Immunogenetics. College of American Pathologists.

This report summarizes the 8-year experience of the DR survey program designed to evaluate the performance of histocompatibility laboratories in the serologic typing of cell specimens for HLA-DR and HLA-DQ polymorphisms and the HLA class II antibody identification and B-cell crossmatching of serum specimens. The number of participants increased from 45 in 1985 to 214 in 1992. Although the performance criteria are based on laboratory consensus, the availability of DNA typing since 1990 has enabled a critical assessment of the reliability of serologic HLA-DR, DQ typing. The survey results shows that unsplit HLA class II antigens DR1-DR8, DR52/53, and DQ1-3 are generally correctly identified in over 90% of the participating laboratories. DR9 and DR10 have not yet been tested and testing for DQ4 has not yet achieved this level on consensus. In contrast, the assignments of serologic subtypes of HLA-DR and HLA-DQ are less consistent and frequently unreliable. Although the B-cell crossmatches show generally high laboratory consensus rates, the serum screening results show frequently inconsistent results regarding HLA class-II-specific antibody identification.

Antibody Specificity↗
PubMed1994

Combined liver-kidney transplantation and the effect of preformed lymphocytotoxic antibodies.

Thirty-eight sequentially placed liver and kidney allografts were evaluated with respect to patient and graft survival, and the influence of preformed lymphocytotoxic antibodies was analysed. The results suggest that the survival rate of combined liver and kidney transplantation is similar to the survival rate of liver transplantation alone. Sequentially placed kidney allografts may be protected from hyperacute rejection in the presence of donor specific lymphocytotoxic antibodies, but not in all instances. Both patient and kidney allograft survival was lower in positive crossmatch patients (33% and 17% respectively) than in negative crossmatch patients (78% and 75%). High levels of panel reactive antibodies (> 10%) also appeared to have a deleterious effect on survival, although the majority of the patients who failed also had a positive crossmatch. Although performed lymphocytotoxic antibodies are not an absolute contraindication to combined liver-kidney transplantation, they do appear to have a deleterious effect on long-term graft survival. However, more correlation with clinical parameters is needed.

Adolescent↗
PubMed1993

The influence of HLA matching on cytomegalovirus hepatitis and chronic rejection after liver transplantation.

Previous findings in liver transplantation patients have raised the concept that HLA plays a dualistic role. HLA matching will reduce rejection but may augment MHC restricted cellular immune mechanisms of liver allograft injury. To evaluate this concept, we studied CMV hepatitis in 399 FK506-treated liver transplant patients, including 355 cases for which complete HLA-A,B,DR,DQ typing information was available. CMV hepatitis developed in 25 patients, and 17 of them (or 68%) showed a one or two HLA-DR antigen match with the donor. In contrast, HLA-DR matches were found in only 35% of 330 patients without CMV hepatitis (P = 0.005). No significant associations were seen for HLA-A, HLA-B, and HLA-DQ antigens. In pretransplant CMV-seronegative patients with seropositive grafts (n = 39), the frequency of CMV hepatitis was 44% for HLA-DR-matched livers but 14% for HLA-DR-unmatched livers. In seropositive recipients (n = 187), these frequencies were 12% and 2% for HLA-DR-matched and unmatched liver grafts. Chronic rejection developed in 29 patients (or 8%) during a follow-up between 10 and 24 months after transplantation. Its incidence was higher in the CMV hepatitis group (24% vs. 6%) (P = 0.007). Although no associations were found between HLA matching and the incidence of chronic rejection, there was an earlier onset of chronic rejection of HLA-DR-matched livers irrespective of CMV hepatitis. These findings suggest that an HLA-DR match between donor and recipient increases the incidence of CMV hepatitis in both primary and secondary CMV infections. Although HLA compatibility leads to less acute cellular rejection, it is suggested that DR matching may accelerate chronic rejection of liver transplants, perhaps through HLA-DR-restricted immunological mechanisms toward viral antigens, including CMV.

Chronic Disease↗