Role of blood transfusions on the induction of antibodies against recognition sites on T lymphocytes in renal transplant patients

Immunomodulation in transfused trauma patients

PURPOSE OF REVIEW

Traumatic injury is a major human health problem, with many injured people supported by transfusion of allogeneic blood. Although trauma and transfusion have both been known to have immunomodulatory effects for some time, little is known about their combined effects or the scope and kinetics of such responses.

RECENT FINDINGS

Traumatic injury has a profound immunomodulatory effect on the patient, affecting a broad array of immunological components. This can be further complicated by transfusion, though the contribution of transfusion relative to the massive response triggered by trauma is small. The response to trauma involves a strong immunosuppressive component, which, contrary to the systemic inflammatory response syndrome/compensatory anti-inflammatory response syndrome model, occurs at the earliest time points examined and overlaps with proinflammatory and antimicrobial elements. This response is remarkably similar in a wide range of patients with different types and severities of injury.

SUMMARY

The response to trauma and transfusion involves a massive and rapid reorganization of the immune system that can put the patient at increased risk of infection, tissue damage, and organ failure. The scope of the response presents challenges to the development of treatments to control this dysregulation.

Transfusion-associated microchimerism: the hybrid within

Microchimerism, the coexistence of genetically disparate populations of cells in a receptive host, is well described in both clinical and physiological settings, including transplantation and pregnancy. Microchimerism can also occur after allogeneic blood transfusion in traumatically injured patients, where donor cells have been observed decades after transfusion. To date, transfusion-associated microchimerism (TA-MC) appears confined to this clinical subset, most likely due to the immune perturbations that occur after severe trauma that allow foreign donor cells to survive. Transfusion-associated microchimerism appears to be unaffected by leukoreduction and has been documented after transfusion with an array of blood products. The only significant predictor of TA-MC to date is the age of red cells, with fresher units associated with higher risk. Thus far, no adverse clinical effect has been observed in limited studies of TA-MC. There are, however, hypothesized links to transfusion-associated graft vs host disease that may be unrecognized and consequently underreported. Microchimerism in other settings has gained increasing attention owing to a plausible link to autoimmune diseases, as well as its diagnostic and therapeutic potential vis-a-vis antenatal testing and adoptive immunotherapy, respectively. Furthermore, microchimerism provides a tool to further our understanding of immune tolerance and regulation.

Distinct roles of trauma and transfusion in induction of immune modulation after injury

BACKGROUND

Trauma and transfusion can both alter immunity, and while transfusions are common among traumatically injured patients, few studies have examined their combined effects on immunity.

STUDY DESIGN AND METHODS

We tracked the plasma levels of 41 immunomodulatory proteins in 56 trauma patients from time of injury up to 1 year later. In addition, a murine model was developed to distinguish between the effects of transfusion and underlying injury and blood loss.

RESULTS

Thirty-one of the proteins had a significant change over time after traumatic injury, with a mixed early response that was predominantly anti-inflammatory followed by a later increase in proteins involved in wound healing and homeostasis. Results from the murine model revealed similar cytokine responses to humans. In mice, trauma and hemorrhage caused early perturbations in a number of the pro- and anti-inflammatory mediators measured, and transfusion blunted early elevations in interleukin (IL)-6, IL-10, matrix metalloproteinase-9, and interferon-γ. Transfusion caused or exacerbated changes in monocyte chemotactic protein-1, IL-1α, IL-5, IL-15, and soluble E-selectin. Finally, trauma and hemorrhage alone increased CXCL1 and IL-13.

CONCLUSIONS

This work provides a detailed characterization of the major shift in the immunologic environment in response to trauma and transfusion and clarifies which immune mediators are affected by trauma and hemorrhage and which by transfusion.

Early Accumulation of Interferon-?? in Grafts Tolerized by Donor-Specific Blood Transfusion: Friend or Enemy?

BACKGROUND

We previously documented an early (day-2) interferon (IFN)-gamma accumulation in cardiac allografts of rats made tolerant by donor-specific blood transfusion (DSBT) but not in rejecting controls. This contrasted with the IFN-gamma peak seen later (day 5) in rejecting but not in tolerant rats.

METHODS

To further examine the role of early intragraft IFN-gamma in DSBT-induced tolerance, we studied whether IFN-gamma up-regulation correlates with the magnitude of the DSBT effect and how IFN-gamma is influenced by interventions abrogating tolerance.

RESULTS

The protective effect of DSBT depended upon the timing of administration: day-12 DSBT induced indefinite graft survival; day-6 DSBT gave a moderate, and day-0 DSBT, no graft prolongation. IFN-gamma up-regulation correlated with the DSBT effect: it was maximal after day-12 DSBT, intermediate after day-6 DSBT, and absent after day-0 DSBT. Tolerant splenocytes transferred tolerance into naive rats in a donor-specific manner, indicating that alloantigen-specific regulatory cells operate. Thymectomy prevented regulatory cells development, caused further amplification of intragraft IFN-gamma, and led to rejection, although graft survival was still prolonged.

CONCLUSIONS

Day 2 intragraft IFN-gamma correlates with the DSBT protective effect. Thymectomy abrogates DSBT-induced tolerance, prevents regulatory cell development, and paradoxically causes further accumulation of intragraft IFN-gamma. These data indicate that DSBT has a stimulatory and a (thymus-dependent) inhibitory effect on early intragraft IFN-gamma. Intragraft IFN-gamma is beneficial, providing it occurs early and remains moderate. The role of intragraft IFN-gamma in tolerance and rejection depends upon the timing and the degree of production and perhaps the type of IFN-gamma producing cells (regulatory or effector).

Inhibition of chronic vascular rejection by donor-specific blood transfusion is associated with a reduction in transforming growth factor-beta1 expression

BACKGROUND

Concentric intimal thickening and the infiltration of inflammatory cells in cardiac allografts are the pathological hallmark characteristics of chronic vascular rejection (CVR), the leading cause of long-term graft failure. The precise mechanisms involved in the development and pathogenesis of CVR remain elusive. In the PVG-R23 to PVG-RT1u rat model of CVR, prior administration of a donor-specific transfusion (DST) was previously shown to prolong graft survival indefinitely and abolish the vascular lesions associated with CVR. The present study investigates in more depth the underlying mechanisms involved in the subsequent prolongation of allograft survival and inhibition of CVR by DST.

METHODS

R23 heart grafts were monitored in nontransfused and transfused RT1u recipients injected 2 weeks before transplantation with 1.5 ml of R23 blood. Severity of arteriosclerosis, transplant infiltrate, transforming growth factor (TGF)-beta1 protein expression within the graft, plasma TGF-beta1 levels, class II MHC expression, tenascin protein expression, and serum alloantibody levels were measured.

RESULTS

There was no significant difference in donor MHC class II, myocardial TGF-beta1, or tenascin expression between DST and non-DST-treated recipients. However, DST-pretreated recipients showed greatly reduced histological evidence of CVR and had lower titers of R23-specific IgG subclasses. Furthermore, DST-treated allograft recipients showed significant decreases in circulating TGF-beta1 levels and a reduction in TGF-beta1 and tenascin expression within coronary arteries of the allografts.

CONCLUSION

The results suggested that DST inhibited CVR by altering and regulating the expression of TGF-beta1, thereby preventing the fibrogenic effects associated with TGF-beta1.

Suppressed cell-mediated immunity and monocyte and natural killer cell activity following allogeneic immunization of women with spontaneous recurrent abortion

Spontaneous recurrent abortion (SRA) has been treated by means of immunization with paternal or third-party white blood cells, yet the immunological basis for SRA and for the role of immunization protocols in pregnancy outcome remains controversial. To elucidate this question, nine women with SRA were immunized with paternal mononuclear cells and studied before and 2 weeks after immunization. Seven women who became pregnant gave birth to live newborns. Secretion of the T helper 1 cytokines IL-2 and interferon-gamma by patients, mononuclear cells decreased, while production of IL-10 increased. The levels of natural killer and lymphokine-activated killer cell-mediated cytotoxicity were markedly decreased. Monocyte functions such as secretion of IL-1 alpha, tumor necrosis factor alpha, IL-6, and cytotoxic activity decreased concurrently with elevations in IL-10 and transforming growth factor beta secretion. Production of IL-12, a pivotal regulatory cytokine, decreased. Furthermore, B7/1 expression on patients' mononuclear cells was downregulated. This resulted in a decrease in monocyte costimulatory activity of purified T cells with soluble anti-CD3, paralleled by a decline in allogeneic proliferative responses. These results suggest that the improved pregnancy success rate in women with SRA following immunization may be partly related to suppression of cell-mediated immunity and monocyte and natural killer cell activity.

Lymphocyte phenotypes and infection incidence in transfused preterm neonates

The immunomodulating effects of repeated exposure to blood from multiple donors coupled with an immature immune system may predispose the preterm neonate to an increased incidence of infection in his first few months of life. To test this hypothesis, we compared lymphocyte phenotypes, serum IgG concentrations, and histories of infection and rehospitalization in neonates at 4 months corrected age. Two of the study groups were preterm infants who had been transfused with either frozen, deglycerolized or CMV-negative, gamma-irradiated blood. Control groups consisted of nontransfused term and preterm infants. There were no differences found in lymphocyte phenotypes or serum IgG concentrations of controls or transfused infants. No differences were found in the infection or rehospitalization incidence in the transfused infants as compared with nontransfused preterm neonates. We failed to show differences in immune parameters or in infection and rehospitalization rates of the preterm infants analysed. Alongside previously published reports, our data suggest that red cell transfusions have a minimal impact on the immature immune system of the neonate.

Donor-specific transfusion and donor bone marrow infusion in renal transplantation tolerance: a review of efficacy and mechanisms

The ultimate goal in transplantation is modulation of the immune response to produce tolerance without immunosuppression. To date only a state of pseudotolerance for the allograft has been achieved through the use of potent pharmacologic and biologic manipulations. Despite these manipulations to prevent acute rejection, chronic rejection eventually results in graft failure. Thus, different strategies have been sought to induce tolerance and prevent acute and chronic rejection. Historically, donor-specific transfusion (DST) was one such strategy attempted. Donor-specific transfusion has been used primarily in living donor organ transplantation. With the concern that DST may sensitize patients, thereby preventing transplantation and introduction of cyclosporine, the use of DST was curtailed. More recently, donor bone marrow (DBM) infusion at the time of cadaveric transplantation has been used to facilitate development of microchimerism and tolerance to abrogate acute and chronic rejection. However, DBM infusion may predispose the recipient to graft-versus-host disease and is not easily accomplished in living donor organ transplantation. The potentially immunomodulating and tolerizing mechanisms of DST and DBM infusion are similar and include induction of anergy, stimulation of anti-anti-HLA antibodies, provision of soluble HLA antigen, suppressor cell and/or veto cell activity, clonal deletion, regulation of cell surface molecules, regulation of cytokines, promotion of microchimerism, or a combination of these. Of these mechanisms, microchimerism with the concomitant persistence of soluble donor HLA antigen is felt by many to be the most important. Although microchimerism is detectable in many patients who are tolerant of their grafts, there is no clear evidence that chimerism is responsible for the induction or maintenance of tolerance.

Renal allograft survival in outbred mongrel dogs using rabbit anti-dog thymocyte serum in combination with immunosuppressive drug therapy with or without donor bone marrow

Therapeutic renal transplantation in dogs is currently being investigated as a treatment for endstage renal disease. This pilot study examines the effect of donor bone marrow (DBM) infusion and antithymocyte serum (ATS) in combination with immunosuppressive drug therapy in prolonging renal allograft survival in dogs. Seven normal outbred mongrel dogs received an unmatched renal allograft. All dogs received rabbit anti-dog thymocyte serum (RADTS), prednisone (Pr), cyclosporine-A (CsA) and azathioprine (Aza). In addition, three dogs (group 1 test) received DBM and four dogs (group 2 control) did not receive DBM. Serum CsA levels were measured throughout the study. Immunosuppressive therapy was gradually reduced with Pr, CsA, and Aza withdrawn at 200, 450, and 680 days, respectively. Allograft rejection was treated with prednisolone sodium succinate. One dog in group 1 and one in group 2 died as a result of infectious canine rhinotracheitis and rejection early in the study. Renal allograft torsion occurred in one group 1 dog. The remaining four dogs survived the 2 years of the study. The dogs in group 2 (three dogs) all rejected the renal allograft after total drug withdrawal, the surviving dog in group 1 did not. This study demonstrates that RADTS, Pr, CsA, and Aza in combination can prolong renal allograft survival in mongrel dogs, whereas DBM may enhance the unresponsive state.

Leukodepleted blood components

The use of leukodepleted blood components may reduce some adverse effects of transfusion in certain clinical situations. This review outlines the recognised effects of contaminating passenger leucocytes, the value of leukodepleted components in preventing some of these complications, methods of leukodepletion and the current recommendations for use of these components.

Effects of pre- and postengraftment donor-specific transfusions and cyclosporine on the enhancement of experimental allograft survival

The tolerogenic effects of immediate pretransplant donor-specific transfusion (DST) with cyclosporine (CsA) have been well described. The purpose of this study was to determine if these effects could be improved upon by the administration of post-transplant DSTs. When added to a 29-day course of CsA, a single DST given 24 hr pretransplant improved graft survival compared to CsA alone (84.9 +/- 12.3 vs 40.0 +/- 8.8 days; P less than 0.05). The administration of an additional DST on post-transplant Days 7, 14, and 21 further improved this survival to 152 +/- 28 days, with 45% of grafts surviving greater than 200 days, until sacrifice. The donor specificity of this effect was demonstrated by the increased survival of second ACI grafts transplanted into Lewis recipients with existing "tolerant" ACI allografts (long-term survivors, or LTS); third-party Buffalo rat hearts transplanted into LTS rats in a similar manner were rejected normally. Loss of graft antigenicity was not seen, as retransplanted ACI hearts obtained from LTS Lewis rats were rejected in a first-order manner. From this we conclude that (1) the addition of multiple post-transplant DSTs improve the enhancement seen with preoperative DST and CsA, (2) loss of graft antigenicity does not contribute to this improved enhancement, and (3) this effect appears to be donor antigen specific.

Immunologic changes after blood transfusion in patients undergoing vascular surgery

Immunologic changes after blood transfusions cannot be studied ethically in normal individuals. We therefore studied two comparable groups of patients with atherosclerotic cardiovascular disease who received similar drug treatment and experienced a similar degree of surgical trauma, except that one group received an average of 2.5 units of packed red cells at one time period during surgery. We conducted immunologic tests preoperatively and 5, 10, 45 to 60, 90, 180, and 360 days postoperatively. There was no significant difference in all indices tested preoperatively between the two groups. Five and 10 days postoperatively, the absolute numbers of CD3, CD4, CD8, and B cells decreased in both groups; however, the decrease was significantly greater in the transfused group than in the nontransfused group 5 days postoperatively. There was no significant difference in these parameters between the two groups at other time periods tested. At 5 and 10 days postoperatively, the lymphocyte responses to phytohemagglutinin, concanavalin A, and allogeneic lymphocytes in autologous serum were decreased in both groups. However, at 60 days postoperatively, the responses of the nontransfused group became significantly increased, whereas those of the transfused group remained relatively unchanged. By days 90, 180, and 360, the lymphocyte responses of the nontransfused group had dropped to levels seen at earlier time intervals and were comparable to responses in the transfused group. There were no significant differences between the groups in the number of T-cell colonies formed, the number of immunoglobulin-producing cells obtained, and the lymphokine responses (migration inhibitory factor/migration stimulation factor) at all times tested. The major immunologic perturbations attributed to blood transfusions were an exaggerated decrease in the numbers of circulating lymphocytes, particularly those with markers associated with T-helper cells, and failure to demonstrate a rebound increase in the proliferative response 45 to 90 days later.

The role of immunization treatment in preventing recurrent abortion

Published reports of controlled studies of immunization treatment in recurrent abortion have not shown any ability of either third-party cells or the husband's cells to prevent further abortions, whereas preliminary results of ongoing studies speak in favor of a beneficial effect of third-party cells. However, the lack of significant differences so far does not prove that immunotherapy in habitual abortion is ineffective, because all of these studies include too few patients in each group to give any conclusive results. Only a mega-trial could evaluate the efficacy and side effects of leukocyte immunotherapy. Such controlled studies are needed to clarify the true benefits, risks, and limitations of immunization treatment in recurrent abortion. Factors such as appropriate inclusion criteria, the time relationship between immunization and the next pregnancy, the number of immunizations required, the cell source and cell doses need to be established. Until this additional information is available this treatment should not be considered routinely indicated. This approach should be restricted to a few centers in order to provide maximal possibilities for collection and evaluation of the data.

Immunomodulation of kidney and heart transplants by anti-idiotypic antibodies

To explore the possibility that circulating HLA antigens from the graft and anti-anti-HLA (anti-idiotypic) antibodies influence the long-term survival of renal and cardiac allografts, analysis of 330 renal allograft recipients and 174 recipients of cardiac allografts was conducted. Anti-donor-HLA antibodies (Ab1) present before or after transplantation are associated with graft failure, whereas irrelevant anti-HLA antibodies had no impact on actuarial graft survival. Ab1 may be uncovered by dissociation of immune complexes and depletion of soluble antigens with monoclonal antibody-coated magnetic beads. Of the 421 sera tested from 65 heart recipients, 97 showed Ab1 before depletion and 178 after depletion; similar rise in positive sera was seen in 39 renal transplant recipients. Three distinct patterns of appearance of Ab1 and Ab2 (anti-Ab1 antibody) were recognized. Patients with cyclic variations of Ab1 in association with Ab2 had 100% graft survival, whereas patients with cyclic variations of Ab1 but no detectable Ab2 had 2-year graft survival of 36% for kidneys and 71% for hearts. Presence of Ab1 in all sera after transplantation led to 47% and 56% 2-year renal and heart allograft survival, respectively.

The effect of a single whole-blood transfusion on cytokine secretion

The effect of a single whole-blood transfusion on the cascade of cytokine secretion was studied in patients with chronic renal failure. The results indicate that 1 week after blood transfusion, no significant changes were observed in the secretion of interleukin-2, colony-stimulating factor, tumor necrosis factor, and gamma-interferon. However, 2 weeks after blood transfusion, a sharp decrease was observed in the generation of these cytokines. A decrease of about 70% was observed in interleukin-2, tumor necrosis factor, and gamma-interferon secretion. The production of colony-stimulating factor 2 weeks after blood transfusion amounted to about 30% less than baseline levels. No statistical differences in interleukin-1 production were observed throughout the study. In addition, we found that the decrease in cytokine secretion was paralleled by a sharp increase in the in vitro secretion of prostaglandin E2. Thus the beneficial effect of blood transfusion on graft survival might be due in part to an immunosuppressive effect brought about by immunoregulatory changes via the cascade of cytokine secretion.

[Effect of the transfusion of blood and hemoderivatives on the prognosis of colorectal cancer]

In recent years in the literature several investigators described a negative effect of perioperative transfusion of blood and hemoderivatives on the prognosis of malignant tumors. Concerning the patients with colorectal carcinoma operated between 1979 and 1983 at Erlangen University Hospital these results could be proven. We observed a significantly worse 5-year survival rate for patients who received perioperative blood transfusion. However, multivariant analysis in Cox-regression model revealed other factors like tumor stage and localisation responsible for the poorer prognosis. Therefore blood transfusion seems not to have any influence on the prognosis itself. Furthermore we observed a significantly poorer prognosis concerning patients who perioperatively received fresh frozen plasma (FFP). Surprisingly multivariant analysis showed that FFP substitution in contrast to blood transfusion has an own prognostic influence. This difference in prognosis cannot be explained by selection criteria. The mechanism of the negative influence of FFP on the prognosis of colorectal carcinoma remains unclear and is investigated currently in prospective studies.

What is known about blocking factors in renal allograft recipients

A variety of substances present in serum or plasma, either at the time of renal transplant or during stable graft function in long-term recipients, may interfere with cell-mediated immune functions. In several cases the presence of serum blocking factors has been correlated with decreased graft vulnerability to acute rejection. The question is: are serum blocking factors important for the induction or maintenance of allograft tolerance or, alternatively, are they merely by-products of the tolerant state? Perhaps the most compelling case for an essential role of serum blocking factors can be made in instances where vigorous cell-mediated immune responses can be demonstrated in vitro, but anergy (for example, absence of DTH response) is seen in vivo. However, in renal transplant recipients the majority of studies that show the presence of receptor blocking antibodies or other immunoregulatory serum factors also found a decreased cell-mediated immune response in vitro. Thus, allograft tolerance would appear to involve multiple mechanisms as suggested elsewhere. Due to the recent discovery of the molecular structure of the T cell receptor 33,34, it is now possible to identify determinants associated with the binding of T cell receptor blocking antibodies in renal transplant recipients; for example, one should be able to determine if families of V beta genes are involved. Alternatively, it may be possible to identify polymorphic structures on T cells other than the alpha, beta receptor complex as ligands for blocking antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

MLC-inhibiting serum in mice after transfusion with 3 M KCl-extracted soluble antigen

Balb/c (H-2d) mice were transfused weekly with 3 M KCl-extracted soluble antigen prepared from splenocytes of C3H/HeJ (C3H)(H-3k) mice. One week after each transfusion, spleen and serum samples were collected from transfused mice and pooled. The serum was absorbed with erythrocytes and spleen cells from C3H mice and heat inactivated. Spleen cells from transfused mice were tested for proliferative responses in mixed lymphocyte culture (MLC) against stimulator cells from the antigen donor C3H or from third party SJL (H-2s) mice. The proliferative responses of lymphocytes from soluble-antigen-transfused Balb/c mice to stimulator cells from C3H and SJL mice were not suppressed. Furthermore, suppressor cells could not be demonstrated in spleens of transfused mice in in vitro coculture experiments. The MLC inhibition test was utilized to investigate the presence of MLC-inhibiting serum from transfused mice. The results demonstrate that serum capable of inhibiting responses of Balb/c mice were induced after three weekly injections of soluble antigen and that this inhibition in MLC was specific for the stimulator cells from the antigen donor C3H mice. These findings differ from our studies using whole blood transfusions where (1) MLC inhibiting antibodies developed in Balb/c mice after only one transfusion of C3H whole blood, and (2) serum from blood transfused mice achieve greater inhibition than soluble-antigen-induced serum. These results suggest that although soluble antigen is capable of inducing MLC inhibiting serum, the kinetics of this induction may be different from transfusion with whole blood.

Disappearance of HLA and platelet-specific antibodies in acute leukaemia patients alloimmunized by multiple transfusions

Alloimmunization by platelet transfusions was studied in 154 patients with acute leukaemia. 17 patients had HLA antibodies at initial presentation induced by previous transfusions or pregnancies; one of these also had platelet-specific antibodies and one other patient had platelet-specific antibodies alone. A further 38 patients developed HLA antibodies during therapy; three also had platelet-specific antibodies and two patients developed platelet-specific antibodies alone. Of these, 37 patients with HLA antibodies including three with platelet-specific antibodies and one patient with platelet-specific antibodies alone survived their initial therapy and formed the basis of this study. Antibodies once detected persisted throughout the study in seven of the 37 patients with HLA antibodies including one patient with platelet-specific antibodies and in the patient with platelet-specific antibodies alone. HLA antibodies disappeared after discontinuation of transfusions in six patients, and after switching to HLA matched platelet transfusions and leucocyte-poor blood in eight patients; two of the latter patients also had platelet-specific antibodies which disappeared. The other 16 patients with HLA antibodies lost their antibodies despite continued transfusions.

Role of MLC serum inhibitory factors in high MLC-reactive kidney transplant recipients pretreated with donor-specific blood transfusion (DST)

In order to clarify the beneficial effect of donor-specific blood transfusions (DST) on kidney allograft survival, sera from 16 patients treated with DST were studied using the mixed lymphocyte culture (MLC) serum inhibition test. The results demonstrate that MLC inhibitory factors could be induced in the serum of the recipients after the completion of DST, and that these factors are directed against cells of the recipient but not against cell from the donor. Regarding the correlation with rejection episodes and clinical outcome, a significant improvement in renal transplant survival and reduction in rejection episodes was observed when MLC inhibitory factors were present in post-DST sera. These data suggest that such factors may contain antibodies directed against recognition sites on T lymphocytes, e.g., anti-idiotypic antibodies, and be associated with prolonged graft survival of living-related, high MLC-reactive one-haplotype-mismatched kidney.

Adverse relationship between blood transfusions and survival after colectomy for colon cancer

Random-donor blood transfusions are deliberately given before cadaver renal allografting to improve allograft survival. Since host modifications that improve the outcome of an allograft might be associated with a decreased ability of the host to control cancer growth, the relationship between blood transfusions and the outcome of 146 Dukes' stages A, B, and C colon cancers treated by resection during the years 1974 to 1979 was studied. It was found that 65 patients (45%) had been transfused and that at 5 years, overall survival was significantly better in the nontransfused patients compared to the transfused patients (0.68 and 0.51 5-year product limit survival fractions respectively; P = 0.03 for unadjusted log-rank comparison of entire survival curves). Relative risk of death due to cancer in transfused patients versus nontransfused patients was 2.3 (P = 0.05) when controlled for sex, age, stage, histologic differentiation, cancer location, and pre-resection hemoglobin level using Cox regression analysis. Thus, blood transfusion appears to be an additional important prognostic variable. The hypothesis suggested but not proven by these data that the outcome for some malignancies may be related to the immunomodulating effects of blood transfusions needs further study.

Induction of donor-specific immune modulation and successful renal transplantation with a simplified method of donor-specific blood transfusion

We developed a new method of donor-specific blood transfusion (DST) for prospective kidney transplant recipients from a living related donor. Forty-four patients were transfused with 100 ml of one-haplotype matched kidney donor's whole blood at 1, 8, and 15 days after its storage. Ten of these patients received azathioprine (1.5 mg/kg per day) in addition to DST. After DST, three patients (6.8%) developed donor-specific lymphocytotoxic antibodies. The incidence of sensitization was not different between azathioprine-treated and untreated patients. Following DST, donor-specific mixed lymphocyte culture (MLC) was significantly suppressed without any accelerated (secondary type) response in early MLC. Subsequently, 24 patients received a kidney transplant from the donor. Graft survival rates were 96% and 90% at 12 and 24 months, respectively. Nine additional patients, seven from a two-haplotype matched sibling and two from a no-haplotype matched sibling also received DST. None of these patients became sensitized following DST, and all have functioning grafts for 6 to 18 months. This study indicates that 100 ml of stored whole blood DST three times at weekly intervals is a practical, less immunizing, and effective approach to enhance graft survival in recipients of a living related donor graft, DST produces donor-specific adaptive responses that might be conductive to successful graft outcome, and this protocol could be used in sibling donor-recipient pairs who do not share a haplotype.

The fetus as an allograft: evidence for antiidiotypic antibodies induced by pregnancy

We tested sera from 20 women [9 parous, 8 with no children, and 3 with abortion(s)] for inhibition in mixed lymphocyte culture (MLC). In these experiments, the responder (wife) lymphocytes were treated with autologous serum and rabbit complement and then tested for responses against stimulator cells from the husband and from third-party allogeneic donors. The results demonstrate that antibodies capable of inhibiting responses of wife's lymphocytes to husband's cells in MLC are present in sera from parous women, but not in women without children and in women with abortion(s). The MLC-inhibiting activity in parous women sera was in the IgG fraction. The results from immunofluorescence and absorption experiments suggest that the inhibition in MLC was due to antibodies directed against recognition sites on wife's T lymphocytes against husband's alloantigens. These observations suggest that antiidiotypic antibodies against husband-specific idiotypes on wife's lymphocytes could be induced by pregnancy and that maternal tolerance to fetus may be attributable to a similar mechanism occurring in vivo.

Blood transfusions in renal dialysis patients. Effect on cellular immune response

The effect of blood transfusions, given in low number (less than 5), on the immune response of renal dialysis patients was studied. A significantly lowered response of lymphocytes to mitogen stimulation was observed in patients after as few as one, two or three transfusions, depending on the patient. This led to an increased delta 48/delta 0 ratio reflected by the enhanced response of the cells following delayed addition of suboptimal dose of mitogen. There was no modification of the ratio of helper/inducer to suppressor/cytotoxic T cells subsets (OKT4/OKT8). The use of such simple in vitro tests in a strict protocol of transfusions could allow an adequate follow-up thereby limiting the risks of sensitization. These results demonstrate that important phenomena affecting patients' immune response are turned on following even a low number of transfusions in the majority of uremic patients. This could probably be related to the beneficial effects of blood transfusions on the kidney allograft survival already described.