Influence of HLA matching and blood-transfusion on outcome of 502 London Transplant Group renal-graft recipients

Transplant Tolerance, Not Only Clonal Deletion

The quest to understand how allogeneic transplanted tissue is not rejected and how tolerance is induced led to fundamental concepts in immunology. First, we review the research that led to the Clonal Deletion theory in the late 1950s that has since dominated the field of immunology and transplantation. At that time many basic mechanisms of immune response were unknown, including the role of lymphocytes and T cells in rejection. These original observations are reassessed by considering T regulatory cells that are produced by thymus of neonates to prevent autoimmunity. Second, we review "operational tolerance" induced in adult rodents and larger animals such as pigs. This can occur spontaneously especially with liver allografts, but also can develop after short courses of a variety of rejection inhibiting therapies. Over time these animals develop alloantigen specific tolerance to the graft but retain the capacity to reject third-party grafts. These animals have a "split tolerance" as peripheral lymphocytes from these animals respond to donor alloantigen in graft versus host assays and in mixed lymphocyte cultures, indicating there is no clonal deletion. Investigation of this phenomenon excludes many mechanisms, including anti-donor antibody blocking rejection as well as anti-idiotypic responses mediated by antibody or T cells. This split tolerance is transferred to a second immune-depleted host by T cells that retain the capacity to effect rejection of third-party grafts by the same host. Third, we review research on alloantigen specific inhibitory T cells that led to the first identification of the CD4+CD25+T regulatory cell. The key role of T cell derived cytokines, other than IL-2, in promoting survival and expansion of antigen specific T regulatory cells that mediate transplant tolerance is reviewed. The precise methods for inducing and diagnosing operational tolerance remain to be defined, but antigen specific T regulatory cells are key mediators.

The HLA System and Immunological Defence against Cancer: A Review

In nonmalignant disease, there have been two mechanisms implicated in the association of HLA antigens with disease. In ankylosing spondylitis, evidence is accumulating for cross tolerance between a bacterial antigen and the HLA-B27 antigen; while in the autoimmune diseases, the involvement of an abnormal immune response gene, associated with A1/B8 haplotype, is strongly suspected. The same haplotype has also been associated with recovery from hepatitis B infection and survival of patients with Hodgkin's disease and acute myeloid leukaemia. At present, there are no techniques to study directly immune response genes in man and so these observations are still strictly academic. However, with increasing interest in the use of immunotherapy in cancer and the demonstration in mice that the major histocompatibility system may be the site of action of soluble mediators of immune memory, understanding the mechanisms of action of the HLA associated resistance factors may enable a more rational approach to immunotherapy in man.

Chronic rejection: a significant role for Th17-mediated autoimmune responses to self-antigens

Despite progress in the field of organ transplantation for improvement in graft survival and function, long-term graft function is still limited by the development of chronic allograft rejection. Various immune-mediated and nonimmune-mediated processes have been postulated in the pathogenesis of chronic rejection. In this review, the authors discuss the important role of alloimmune responses to donor-specific antigens and autoimmune responses to tissue restricted self-antigens in the immunopathogenesis of chronic rejection following solid organ transplantation. In particular, the authors discuss the role of induction of Th17-type autoimmune responses and the crosstalk between autoimmune and alloimmune responses. These self-perpetuate each other leading to activation of profibrotic and proinflammatory cascades that ultimately result in the development of chronic rejection.

A prospective, randomized trial of pretransplant blood transfusions in cadaver kidney transplant candidates. Leuven Collaborative Group for Transplantation

To assess the effect of pretransplant blood transfusions on the outcome of cadaveric kidney transplantation, a single-centre analysis was performed of 171 patients randomly assigned to receive no pretransplant transfusion (n = 85) or to receive at least three random blood transfusions (n = 86). After transfusion 18 of the latter patients developed circulating lymphocytotoxic T-cell antibodies, but the sensitization was only transient. At the time of transplantation, none was still sensitized. In both groups 60 patients have been transplanted. Patient and graft survival rates were significantly higher in the transfused group than in the non-transfused group. In the non-transfused patients the higher mortality was due to complications related to repeated anti-rejection therapy. Non-transfused patients had more repeated acute rejection episodes than the transfused patients. The present study indicates that pretransplant blood transfusions still facilitate graft acceptance even in the setting of good HLA matching and with cyclosporine as the basic immunosuppressant. The risk of sensitization is very low.

Cell-cell interaction in graft rejection responses: induction of anti-allo-class I H-2 tolerance is prevented by immune responses against allo-class II H-2 antigens coexpressed on tolerogen

The intravenous sensitization of C57BL/6 (B6) mice with class I H-2-disparate B6-C-H-2bm1 (bm1) spleen cells results in almost complete abrogation of anti-bm1 CD8+ helper (proliferative and interleukin 2-producing) T cell (Th) activities. Although an appreciable portion of CD8+ cytotoxic T lymphocyte (CTL) precursors themselves remained after this regimen, such a residual CTL activity was eliminated after the engrafting of bm1 grafts, and these grafts exhibited prolonged survival. In contrast, the intravenous sensitization with (bm1 x B6-C-H-2bm12 [bm12])F1 cells instead of bm1 cells failed to induce the prolongation of bm1 graft survival as well as bm12 and (bm1 x bm12)F1 graft survival. In the (bm1 x bm12)F1-presensitized B6 mice before as well as after the engrafting of bm1 grafts, anti-bm1 CTL responses that were comparable to or slightly stronger than those observed in unpresensitized mice were induced in the absence of anti-bm1 Th activities. bm1 graft survival was also prolonged by intravenous presensitization with a mixture of bm1 and bm12 cells but not with a mixture of bm1 and (bm1 x bm12)F1 cells. The capacity of CD4+ T cells to reject bm12 grafts was eliminated by intravenous presensitization with antigen-presenting cell (APC)-depleted bm12 spleen cells. However, intravenous presensitization with APC-depleted (bm1 x bm12)F1 cells failed to induce the prolongation of bm1 graft survival under conditions in which appreciably prolonged bm12 graft survival was induced. More surprisingly, bm1 graft survival was not prolonged even when the (bm1 x bm12)F1 cell presensitization was performed in CD4+ T cell-depleted B6 mice. This contrasted with the fact that conventional class I-disparate grafts capable of activating self Ia-restricted CD4+ as well as allo-class I-reactive CD8+ Th exhibited prolonged survival in CD4+ T cell-depleted, class I-disparate cell-presensitized mice. These results indicate that: (a) intravenous presensitization with class I- and II-disparate cells fails to reduce anti-allo-class I rejection responses that would otherwise be eliminated using only class I-disparate cells; (b) such failure is generated according to the coexpression of both classes of alloantigens on a single cell as tolerogen; and (c) allo-class II antigens coexpressed on tolerogen function to activate CD4+ as well as non-CD4+ Th leading to the generation of anti-class I effector T cell responses.

Effect of the number of pregraft blood transfusions in kidney graft recipients treated with bioreagents and cyclosporin A

The impact of a systematic, nondonor-specific, pregraft blood transfusion (BT) protocol was evaluated retrospectively in 446 consecutive, first renal transplant recipients with regard to graft survival rate, rejection, and incidence of infectious episodes. Cyclosporin A was the maintenance immunosuppressive treatment in all patients after a 2-week course of antithymocyte globulin or anti-IL-2 monoclonal antibody. Recipients were assigned to three groups according to the number of pregraft BT (one or two, three or four, or more than four). When nonimmunological failures were excluded from the study, patients receiving three or four BT had statistically better graft survival (P less than 0.02) and a lower incidence of rejection episodes (P less than 0.05) than those in the other groups. There were no significant differences between the three groups in the distribution of HLA mismatching (A, B and DR), time interval between the last BT and transplantation, DR6 recipient phenotype, or nonimmunological failures. Our results show that the number of pregraft BT is an important factor in transplantation.

Heterogenous graft rejection pathways in class I major histocompatibility complex-disparate combinations and their differential susceptibility to immunomodulation induced by intravenous presensitization with relevant alloantigens

The present study investigates the heterogeneity of graft rejection pathways in class I major histocompatibility complex (MHC)-disparate combinations and the susceptibility of each pathway to immunomodulation induced by intravenous presensitization with alloantigens. Depletion of CD8+ T cells was induced by repeated administration of anti-CD8 monoclonal antibody. CD8+ T cell-depleted mice failed to generate anti-allo class I MHC cytotoxic T cell (CTL) responses but exhibited anti-allo class I MHC T cell responses, such as mixed lymphocyte reaction (MLR)/IL-2 production, that were induced by CD4+ T cells. In contrast, donor-specific intravenous presensitization (DSP), as a model of donor-specific transfusion, induced almost complete elimination of CD4+ and CD8+ T cell-mediated MLR/IL-2 production, whereas this regimen did not affect the generation of CTL responses induced by DSP-resistant elements (CD8+ CTL precursors and CD4+ CTL helpers). Prolongation of skin graft survival was not induced by either of the above two regimens alone, but by the combination of these. Prolonged graft survival was obtained irrespective of whether the administration of anti-CD8 antibody capable of eliminating CTL was started before or after DSP. The combination of DSP with injection of anti-CD4 antibody also effectively prolonged graft survival. However, this was the case only when the injection of antibody was started before DSP, because such antibody administration was capable of inhibiting the generation of CTL responses by eliminating DSP-resistant CD4+ CTL helpers. These results indicate that (a) the graft rejection in class I-disparate combinations is induced by CD8+ CTL-involved and -independent pathways that are resistant and susceptible to DSP, respectively; (b) DSP contributes to, but is not sufficient for, the prolongation of graft survival; and (c) the suppression of graft rejection requires an additional treatment for reducing DSP-resistant CTL responses. The results are discussed in the context of potential clinical application in attempts to inhibit the generation of DSP-resistant CTL responses upon the prospective DSP.

Role of major and minor histocompatibility antigens in the suppression of alloreactive cytotoxic responses induced by alloantigen pretreatment

We have recently shown that priming mice with allogeneic strain A spleen cells before immunization with (A x B)F1 spleen cells strongly suppresses the cytotoxic T-lymphocyte (CTL) response directed against linked strain B alloantigens. This specific decrease in the CTL responses against the second immunizing alloantigen is associated with a high CTL response against the first priming alloantigen. The suppression of CTL responses against the strain B alloantigens is, however, not due to killing of F1 spleen cells by anti-A CTL, since it was observed after immunization of primed mice with a mixture of (A x B)F1 and B cells. In the present study, attempts were made to determine the relative contribution of H-2 and minor histocompatibility background antigens towards induction of suppression. Our results demonstrate that priming and immunizing spleen cells have only to share H-2 antigens in order to induce a downregulation of CTL responses directed against the linked alloantigens. This indicates that immunity against H-2 antigens is sufficient to induce suppression. However, priming against minor histocompatibility antigens also induces suppression, but only if spleen cells used for priming and immunization share H-2 antigens with the recipient strain. Therefore, the suppression can be induced by priming with non-H-2 antigens but is H-2-restricted. This study has also demonstrated that suppression can be induced by intraperitoneal or subcutaneous administration of allogeneic cells.

Induction of anti-allo-class I H-2 tolerance by inactivation of CD8+ helper T cells, and reversal of tolerance through introduction of third-party helper T cells

The intravenous sensitization of C57BL/6 (B6) mice with class I H-2-disparate B6-C-H-2bm1 (bm1) spleen cells resulted in the abrogation of CD8+ T cell-mediated anti-bm1 (proliferative and interleukin 2-producing) T helper (Th) cell activities. In vitro stimulation of lymphoid cells from these mice with bm1 cells, however, generated a reduced, but appreciable, anti-bm1 cytotoxic T lymphocyte (CTL) response. Moreover, the anti-bm1 CTL response, upon stimulation with [bm1 x B6-C-H-2bm12 (bm12)]F1 spleen cells, was enhanced when compared with the response induced upon stimulation with bm1 cells. These in vitro results were reflected on in vivo graft rejection responses; bm1 skin grafts engrafted in the bm1-presensitized B6 mice exhibited prolonged survival, whereas (bm1 x bm12)F1 grafts placed collateral to bm1 grafts (dual engrafted mice) inhibited the tolerance to bm1. In the B6 mice 1-2 d after rejecting the bm1 grafts, anti-bm1 Th activities remained marginal, whereas potent anti-bm1 CTL responses were found to be generated from their spleen cells. Administration in vivo of anti-CD4 antibody into bm1-presensitized, dual graft-engrafted mice prolonged bm1 graft survival and interfered with enhanced induction of anti-bm1 CTL activity. These results indicate that anti-class I alloantigen (bm1) tolerance as induced by intravenous presensitization with the relevant antigens is not ascribed to the elimination of CD8+ CTL precursors, but to the specific inactivation of CD8+ Th cells, whose function can be bypassed by activating third-party Th cells.

Mechanism, pathophysiology, diagnosis, and management of renal transplant rejection

In recent years, there has been a steady progress in basic research (immunogenetics and cellular immunology) that helped us in understanding the mechanisms underlying allograft rejection. Several laboratory tests were developed, and the results were shown to correlate with clinical rejection. However, most of these studies have not found a place in clinical practice because of their nonspecificity, lack of sensitivity, time lag, added expense, and inconvenience. The commonly employed diagnostic tests (i.e., renal transplant ultrasound and 131I hippuran scintigram) are helpful in differentiating rejection from other causes of graft malfunction. The specific renal parenchymal disease, such as acute or chronic rejection or de novo or recurrent glomerular disease, contributing to graft malfunction can only be diagnosed by renal histopathologic study. Because hyperacute and accelerated acute rejections are irreversible and necessitate graft nephrectomy, measures should be taken to prevent this problem. High-dose corticosteroids still remain the mainstay of therapy for acute cellular rejection. In the case of steroid-resistant rejections, treatment with ALG or OKT3 appears promising. As there is no effective therapy for chronic allograft rejection, usual measures of delaying the progression of chronic renal failure should be employed, and patients should be advised to return to maintenance dialysis before they develop uremic symptoms. If current experiments demonstrating selective immunosuppression with monoclonal antibodies are found successful in human trials, one can expect further improvement in the outcome of renal transplantation.

Frozen red cells

The popularity and the promise of frozen red cells during the 1970s were largely attributable to logistic problems associated with 21-day storage and to the fringe benefits of white cell and plasma depletion that minimized alloimmunization and febrile transfusions and, it was speculated, reduced the risk of HBV transmission. Filtration, particularly with the new generation of filters now appearing on the market, promises to achieve an equivalent reduction in white cells at a fraction of the cost and inconvenience. Donor testing for HBV and anti-HIV and, as would appear from recent data, the ALT assay as a surrogate test for non-A, non-B hepatitis, have reduced the incidence of transmission of these diseases below the level where either evaluating or utilizing red cell freezing would be practically or economically feasible. The use of frozen red cells following rejuvenation will certainly be replaced by effective resuspension solutions that will permit rejuvenation, washing, and additional weeks of refrigerated storage. Barring some wholly unexpected and improbable development bringing the cost and convenience of frozen red cells close to those of refrigerated cells, there is little reason to believe that frozen red cells will find applications in the civilian market, except for the storage of rare types and, possibly, the prevention of CMV transmission in the foreseeable future. The original goal of red cell freezing, to make long term storage possible, has been fully realized. The rest is history.

Recipient lymphocyte sensitivity to methylprednisolone affects cadaver kidney graft survival

In 42 recipients of mixed-lymphocyte-culture (MLC) incompatible cadaver kidneys and conventional immunosuppressive treatment (azathioprine and steroids) the concentrations of methylprednisolone suppressing the in-vitro response of pretransplant lymphocytes to phytohaemagglutinin by 50% (ED50) were determined. 1-year graft survival was significantly higher in 21 recipients with methylprednisolone ED50 values below the median than in 21 patients with higher than median ED50s (86% v 29%; p less than 0.0002). Thus, the steroid sensitivity of recipients strongly influences the survival of MLC-mismatched kidneys. In 42 transplant recipients treated with cyclosporin and steroids, the effect of steroid sensitivity was also apparent (1-year graft survival 76% and 57% for recipients with low and high ED50, respectively), though not significant. Determination of the sensitivity to steroids may be valuable in determining which recipients can be given HLA-DR-mismatched kidneys and may serve as a guideline for determining the dose of steroids to be used.

Long-term follow-up in London Transplant Group recipients of cadaver renal allografts. The influence of HLA matching on transplant outcome

The London Transplant Group followed 1341 patients with cadaver renal transplants, none of whom received cyclosporine, for six months to 14 years to determine the effect on graft survival of matching donor and recipient for HLA Class I antigens (HLA-A, -B, and -C) and Class II antigens (HLA-DR, -MT, and -DQ). Long-term graft survival was greatly improved by matching for HLA Class I antigens, especially HLA-B. Transplants that could not be matched for both B-locus antigens but were completely matched for Bw4/Bw6 also did very well. In addition, since 1978, excellent results have been obtained with HLA-DR and -DRw52/53 (HLA-MT) matching, but not with HLA-DQ matching. Multivariate analysis using the Cox regression model confirmed that combination Class I and Class II matching produced significant improvements in graft survival. Thus, transplants matched for HLA-DR plus HLA-B and those matched for HLA-MT plus HLA-B had excellent results--even better than those reported with cyclosporine treatment. Double HLA-MT incompatibilities yielded the poorest results. We conclude that this approach of combining the broad and narrow specificities of Class I and II is extremely practical and that appropriate matching of tissue types is clinically important.

Renal transplantation in the United Kingdom and Ireland--the centre effect

A detailed audit was done of eight of the twenty-nine transplant centres serving the UK and Ireland. These 8 centres account for one-third of the total renal transplant operations in these two countries. Information was obtained from each centre by means of a comprehensive questionnaire, a 1 1/2 day visit by the three authors, and an analysis of 50 consecutive first cadaver transplants. The 8 centres were chosen in the knowledge that 4 had high and 4 had low 3-month graft-survival rates. Our audit confirmed a centre effect, with a range in 1-year patient survival of from 82% to 96% and of first cadaver graft survival of from 54% to 82%. The two main factors affecting success rate were the rate of irreversible acute rejection and death with a functioning kidney. Our investigations suggested that the centre variation in acute rejection was influenced by blood transfusion and the variation in mortality by steroid dose and recipient age. Careful and well-organised clinical management cannot be easily quantified but was thought to have an important influence. Widespread adoption of pre-transplant blood transfusion and increasing use of cyclosporin will probably contribute to the further lessening of the centre effect which has already been observed over the past few years.

Prevention of acute tubular necrosis in cadaveric kidney transplantation by the combined use of mannitol and moderate hydration

Recent studies have indicated that maximal hydration of the transplant recipient can substantially reduce the incidence of acute tubular necrosis (ATN). However, this policy requires invasive hemodynamic monitoring, prolonged mechanical ventilation, and bears the risk of overhydration. In a prospective trial we studied the incidence of ATN in recipients of cadaveric kidneys after restricted fluid infusion (Group 1, N = 21), after restricted fluid infusion along with 250 ml of mannitol 20% (Group 2, N = 19), and after a moderate hydration policy together with 250 ml mannitol 20% (Group 3; N = 21). Donor- and preoperative recipient parameters were comparable in all three groups. The total amount of fluid administered and the incidence of ATN were as follows: Group 1-1059 +/- 371 ml and 43%; Group 2-1548 +/- 622 ml and 53%; and Group 3-2529 +/- 675 ml and 4.8%. The moderate hydration policy in Group 3 resulted in a significantly higher peroperative systolic blood pressure compared to Groups 1 and 2. We did not observe any problems related to overhydration. The reduction of ATN incidence led to a substantial decrease in the number of hemodialysis treatments, radionuclide scans, ultrasound investigations, transplant biopsies, and rejection episodes in the first 3 months after transplantation. It is concluded that moderate fluid administration of 2.5 liters during the transplant procedure together with infusion of 250 ml of mannitol 20% immediately before vessel clamp release reduces the incidence of postoperative ATN below five per cent. The procedure is safe, simple, and does not require invasive hemodynamic monitoring.

Possible mechanism of action of transfusion effect in renal transplantation

The mechanism by which blood transfusions given before renal transplantation improves allograft survival was studied in 31 transplant recipients. The presence of non-cytotoxic, Fc receptor blocking antibodies to donor and leukaemic B lymphocytes in pre-transplant sera correlated with both improved graft survival (p less than 0.03 and less than 0.1, respectively) and the number of blood transfusions given (p less than 0.05 and less than 0.03, respectively). Moreover, 6 out of 10 previously untransfused prospective transplant recipients developed these potentially protective antibodies during a course of elective blood transfusions. These results indicate that such non-cytotoxic, Fc receptor blocking antibodies in pretransplant recipient sera (a) are associated with improved allograft survival, (b) correlate with the number of blood transfusions given, and (c) can develop in response to blood transfusion.

The use of dermal antigen testing in predicting the outcome of renal transplantation

The responses to dermal antigen testing to a variety of antigens were measured in patients on regular dialysis. Forty-eight patients have received renal allografts and graft survival was assessed at 6 months. The antigens used were mumps, monilia, streptokinase/streptodornase, tuberculin and dinitrochlorobenzene (DNCB). The responses to these antigens were recorded using standard methodology. The response failed to correlate with graft survival in these patients when compared singly or in combination. Matching at the HLA-B locus was also correlated with graft survival. Of 31 patients with a match at this locus, 22 (71 per cent) have functioning grafts at 6 months, compared with only 4 of 13 (31 per cent) of patients with no match at the B locus (P less than 0.05). When matching at the B locus and DNCB scores were taken in combination, it became evident that those patients with no match at the B locus and low DNCB reactivity all rejected their kidneys within 4 months of transplantation.

Induction of high kidney graft survival rate by multiple transfusion

In 33 centres that adopted a policy of liberal preoperative blood transfusion 174 recipients of cadaver donor transplants were followed up. Those who received no pretransplant transfusions had a 23% 1-year graft survival rate whereas those who had greater than 10 transfusions had an 87% survival rate (p less than 0.000001). 3% of those transfused acquired highly reactive cytotoxic antibodies and greater than 70% had no antibodies, so transfusions do not exert their beneficial effect by excluding strong immune responders. Since transplant survival rates improved with the number of transfusions, they probably produce their beneficial effect by inducing a state of unresponsiveness. Multiple transfusion seems a simple and effective way of improving kidney transplant survival rates. Moreover, the immunosuppressive effect is specific in that it does not alter the immune response to infectious agents.

An analysis of 100 primary cadaver kidney transplants

A multifactorial analysis of 100 consecutive first cadaver kidney transplants was done to document the current status of this treatment for end stage renal disease and to determine the influence of the following variables on kidney losses owing to rejection: splenectomy, pre-transplant transfusions, transfusion at the transplantation, recipient sex, pre-transplant nephrectomy, donor and recipient A, B or O blood group, human leukocyte A and B antigen mismatches, kidney preservation method, donor treatment with methylprednisolone and cyclophosphamide, recipient treatment with antilymphocyte serum or antilymphoblast globulin and a low dose of steroid treatment for rejection. Pre-transplant splenectomy for leukopenia, 5 or more pre-transplant blood transfusions and pre-transplant transfusions without development of circulating cytotoxic antibodies significantly reduced kidney losses owing to rejection (p less than 0.05)., A low dose of steroid treatment for rejection resulted in a trend towards improved patient survival without sacrificing kidney graft survival. Clinical studies demonstrating decreases in kidney graft rejection should be controlled for pre-transplant blood transfusions and, possibly, for pre-transplant splenectomy for hypersplenism.

The role of various risk factors in living related donor renal transplant success

Assessment of living related donor (LRD) survival statistics offers the opportunity to gauge the effects of recipient characteristics without the perturbations of viability, function, and antigen sharing that are inherent in cadaveric organ grafting. From January 1, 1969 to January 1, 1979, 167 LRD grafts were performed. Crude patient survival at one year is 92% and 84% at five years. Graft function at one year is 79%, and at five years it is 64%. One year patient survival has steadily improved: 1969-73: 83%, 1973-75: 91%, 1975-79: 98%. Graft survival improved during the first two periods and has since remained unchanged. HLA identical grafts showed the expected advantage compared with single haplotype grafts (93 vs 74%). Recipient age was without effect until 50 years, all younger subgroups having one-year patient survival of 92-95%, while those older than 50 had a one-year survival of 60%. Juvenile diabetes was associated with a one-year patient survival of 85% and graft survival of 74%. Glomerulonephritis did not affect early graft survival statistics, but there was a greater frequency of graft loss after 2.5 years, with function at five years of 51 versus 68% for recipients with all other diagnoses. Cadaveric graft statistics vary with recipient race when adjusted to exclude older patients and diabetics, white recipient one-year graft survival 74%, black 38%. No meaningful difference exists among LRD recipients as to graft function, but there is a trend toward improved black patient survival. This suggests that there is not an inherent difference in immune response to genetically similar grafts, but that the disparate results with racially mixed donor-recipient combinations rests with other factors.

Role of humoral presenitization in human renal transplant rejection

A prospective study of 31 cadaveric renal allograft recipients was performed to determine the significance of pretransplant presensitization undetected by the conventional microlymphocytotoxicity crossmatch. Donor-specific humoral presensitization revealed by the antibody-dependent cell-mediated cytotoxicity assay (ADCC) was associated with a high incidence of early graft rejection. Six-month graft survival was 20% in recipients with positive pretransplant ADCC and 75% in ADCC-negative recipients (P < 0.01). Among recipients highly presensitized to a random panel of HLA antigens, donor-specific humoral presensitization detected by chromium-51-release complement-dependent cytotoxicity (51Cr-CDC) was also highly correlated with accelerated rejection (P < 0.05). Pathologic study of the rejected allografts revealed antibody-mediated rejection vasculitis in all recipients. We conclude that humoral presensitization undetected by current conventional methods plays a cardinal role in early renal graft rejection and is a major factor responsible for low cadaveric renal transplant survival. This study suggests that use of the ADCC and 51Cr-CDC as routine adjunctive crossmatch procedures may contribute to improvement in renal transplant survival rates.

Endogenous cell-mediated immunity, blood transfusion, and outcome of renal transplantation

The cell-mediated immunity (CMI) of a group of patients on regular dialysis was measured by a quantitative dinitrochlorobenzene (DNCB) skin test, the reaction being graded 0--15. The score in these patients varied widely, although the mean was much lower than that occurring in a group of 15 healthy subjects. 55 cadaveric renal allografts were subsequently done in 51 of these patients, and graft survival was assessed at 6 months. The 39 patients with weak DNCB skin reactions had a much higher graft survival (71%) than did the 12 with strong reaction (15%) (p less than 0.01). The weak DNCB reactors also had more pre-transplant blood transfusions. The findings suggest that the CMI of the recipient as measured by the DNCB test has an important influence on subsequent graft survival. This influence may partly be related to pre-transplant blood transfusion.

Mixed-lymphocyte culture response in a related and an unrelated Australian population

In 256 related combinations in an Australian Caucasian population, the relative responses in one-way mixed-lymphocyte cultures can be divided into four different groups: (i) HLA zero-haplotype different; (ii) HLA-D homozygous-versus-heterozygous; (iii) HLA one-haplotype different: and (iv) HLA two-haplotype different. The median relative responses of the groups were 0.78%, 20%, 64% and 86.5%, respectively; 17.7% of HLA-A, HLA-B identical siblings were found to stimulate significantly in mixed-lymphocyte culture, and 6.3% of HLA one-haplotype different combinations had weak responses. The median relative response of 225 unrelated random combinations was 100%. One mixed-lymphocyte culture combination in this group gave a relative response of 20%, which was found to be a HLA-D homozygous-versus-heterozygous response. A relative response of 20% in mixed-lymphocyte cultures may be taken to indicate relative HLA-D compatibility and would, therefore, predict a favourable outcome in kidney transplantation. The use of mixed-lymphocyte cultures as a routine in selecting suitable donors in living related transplants and, retrospectively, in monitoring the results of cadaveric transplants, is advocated.

Polyclonal antibody secretion induced in human mixed lymphocyte cultures

In mixed leucocyte culture (MLC), using human spleen cells or thoracic duct lymphocytes, antibody secretion was induced, measured as plaque-forming cells (PFC) in a haemolysis-in-gel assay with fluorescein isothiocyanate (FITC)-coupled sheep erythrocytes (SRBC) as targets. Peak antibody secretion was seen on day 5. Using protein-A-coupled SRBC as targets and developing antisera, antibody secretion in MLC was found to be of IgM, IgG and IgA type. There was no correlation between the number of PFC against FITC-SRBC in MLC and DNA synthesis. Supernatants from MLC failed to induce antibody secretion.

Role of blood transfusions and pregnancies in kidney transplantation

A retrospective study in 71 cadaver renal transplant patients showed a significantly better 2-year graft survival rate (62%) in patients who received pretransplant transfusions or who were parous than in nontransfused patients or patients who have not been pregnant (29%). The beneficial influence of blood transfusion and of pregnancy is thus confirmed. An additive effect of blood transfuion and pregnancy is suggested by the results of this study.

The effect of blood transfusion on the immune response and renal graft survival in the Chacma baboon

There is uncertainty about the role of blood transfusion of potential kidney graft recipients. In this study baboons were transfused under conditions mimicking the clinical situation and then callenged with kidney allografts. Eleven baboons were transfused 10 times with blood from different donors. Lymphocytotoxic antibodies induced against the separated B and T cells of a panel of 12 normal baboons were as follows: B-T- 30%; B+T- 3%; B-T+ 1% and B+T+ 66%. Kidney transplantations were done from donors against which the recipients had negative B-T- cross-matches. Median allograft survival time (MST) of 12 days in this group, which was immunosuppressed with azathioprine and prednisolone, was not prolonged when compared with non-transfused, immunosuppressed animals (MST 12 days). A second group of 14 animals was screened for cytotoxins after each transfusion against a panel of five to six normal baboons. The antibody profile of 80 combinations tested after three transfusions was as follows: B-T- 65%; B+T- 16%, B-T+ 0% and B+T+ 19%. Transplantation was with donors against which the transfused recipient had formed B+T- antibodies. Kidney allograft survival was again not prolonged (MST 13 days) but the mean serum creatinine level 8 days after transplantation was significantly lower than that observed in the first group.

Absence of immunization effect in human-kidney retransplantation

We examined whether rejection of a previous graft rendered a recipient immunized against subsequent kidney transplants in over 1900 retransplants. The one-year survival rate (43 +/- 1 per cent [ +/- S.E.M.]) of second grafts from cadaver donors was only slightly (but statistically significantly) lower than that of first transplant (47 +/- 1 per cent, P less than 0.02). Repeated HLA mismatches in 180 second transplants did not show a lower survival rate than 925 grafts with no repeated HLA incompatibility. We conclude that the danger of immunization by previous grafts has been overemphasized from studies in laboratory animals. Those who rejected the first graft rapidly (high responders) had significantly shorter survival of the second graft compared with those who rejected the initial graft slowly (low responders) (60 +/- 3 versus 31 +/- 3 per cent at one year, P less than 0.00001).

Matching for HLA antigens of A, B, and DR loci in renal transplantation by Eurotransplant

79 patients and their respective cadaveric kidney donors were typed for HLA-A, HLA-B, and HLA-DR antigens using frozen stored spleen lymphocytes and fresh peripheral-blood lymphocytes. The kidney-graft survival-rate at 3 to 18 months was highest when donor and recipient shared one or two DR antigens and three or four A and B antigens. The graft-survival rate was significantly higher (87 +/- 6%) at 18 months in these patients than in less well matched patients (48 +/- 9%).