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Background: We previously reported that transduction of the human interleukin (IL)-10 gene into the total fetal liver stem cells (hIL-10-TFLs) of mice protects against their rejection in an allogeneic host. In this study, we explored the effects of these cells in two different models of organ transplantation., Methods: Balb/c mice were sublethally irradiated before receiving skin or vascularized heterotopic heart grafts from C57Bl/6 mice. TFLs from C57Bl/6 mice transduced with hIL-10 or untransduced TFLs were injected on the day of transplantation into recipient mice once or also every 20 days thereafter., Results: Skin allograft survival was prolonged for up to 17.8±0.6 days, vs. 9.0±0.4 days, in mice that received hIL-10-TFLs or untransduced TFLs, respectively. Allogeneic heart transplants survived for 86.25±13.8, 46.3±4.6, 28.1±6.1, or 11.5±0.6 days in mice that received repeated injections of hIL-10-TFLs, a single injection of hIL-10-TFLs, repeated injections of untransduced TFLs, or controls, respectively. Histological analyses of the grafts showed fewer inflammatory foci and CD8+ infiltrating cells in mice injected with hIL-10-TFLs compared with untreated mice. Expressions of H-2b and hIL-10 were found in several organs, including the thymus, liver, and the transplant, in hIL-10-TFL-injected mice. Finally, in hIL-10-TFL-injected mice, FoxP3 T cells were present inside the transplanted heart as late as 140 days after transplantation., Conclusions: In this study, we showed that repeated injections of hIL-10-TFLs are efficient in mitigating transplant rejection. This "prope" tolerance was associated with survival of donor hematopoietic cells in the host.

Background: The increased incidence of skin cancers in transplant patients is well documented; however, few data exist on the risk of subsequent skin tumors in a given patient after the first skin cancer. The aim of this study was to compare the individual rate of subsequent skin cancers in kidney (KTR) and heart transplant recipients (HTR) after the first squamous cell carcinoma (SCC) and to assess risk factors for tumor multiplicity., Methods: In all, 188 patients (121 KTR/67 HTR) were studied for up to 5 years. The cumulative number of SCC, basal cell carcinomas, Bowen's diseases, premalignant keratoses, and keratoacanthomas was recorded yearly after the first SCC., Results: Overall, 71% of patients developed 757 new skin tumors. At 5 years, 100% of HTR and 88% of KTR had presented new tumors. However, the mean number of all tumors was significantly higher in KTR (3.4 vs. 2.0, 4.8 vs. 2.6, 6.6 vs. 2.9, 8.5 vs. 3.5, and 9.7 vs. 4.6 at 1, 2, 3, 4, and 5 years, respectively). Transplantation before 1984, multiple tumors at first consultation, eye and hair color, and skin type were predictive of multiple tumors. Early minimization of immunosuppression and of sun exposure tended to be associated with a reduced rate of all tumors and of SCC, respectively., Conclusions: Although the proportion of HTR developing new tumors is greater as compared with KTR, the mean number of tumors per patient is higher in KTR. This could be due to a longer immunosuppression in patients younger at transplantation.

Background: Induction therapy with antithymocyte globulin (ATG) reduces the incidence of acute rejection after transplantation. A study was undertaken to assess the efficacy and safety of ATG induction on tacrolimus-based and cyclosporine A (CsA)-based therapies compared with immediate tacrolimus triple therapy in kidney transplant recipients., Methods: In a 6-month, open-label, randomized, prospective study conducted in 30 European centers, 555 renal transplant patients were randomly assigned to tacrolimus triple therapy (Tac triple, n=185), ATG induction with tacrolimus (ATG-Tac, n=186), or ATG induction with CsA microemulsion (ATG-CsA, n=184); all were combined with azathioprine and corticosteroids. The primary endpoint was incidence and time to first acute rejection episode confirmed by biopsy., Results: Patient demographics and clinical parameters at baseline were similar. Patient and graft survival rates were similar in all groups. The incidence of clinically apparent acute rejection was significantly higher (P=0.003) for Tac triple (33.0%) compared with ATG-Tac (22.6%) and the incidence for ATG-Tac was significantly lower (P=0.004) than for ATG-CsA (37.0%). The incidences of acute rejection confirmed by biopsy (primary endpoint) were 25.4%, 15.1%, and 21.2% for Tac triple, ATG-Tac, and ATG-CsA, respectively (Tac triple vs. ATG-Tac, P=0.004). The incidences of corticosteroid-resistant acute rejection were 7.0% (Tac triple), 4.8% (ATG-Tac), and 10.9% (ATG-CsA) (ATG-Tac vs. ATG-CsA, P=0.038). In the ATG groups, the incidences of leukopenia, thrombocytopenia, serum sickness, fever, and cytomegalovirus infection were significantly higher (P<0.05)., Conclusions: Acute rejection was significantly lower in the ATG-Tac group compared with the ATG-CsA and Tac triple groups. Significantly more hematologic and infectious adverse events were observed in both ATG induction groups.

Kaposi's sarcoma (KS) develops in 0.5-5% of organ transplant patients; it usually regresses upon treatment reduction, but this may result in graft loss necessitating return to dialysis and/or retransplantation. Until now posttransplantation KS is considered to recur upon reintroduction of immunosuppressive treatment, a fact that has limited retransplantation of patients with previous KS. We report a patient with posttransplantation KS who received a second renal transplantation after having been off immunosuppressive treatment for 10 years, in whom KS has not recurred more than 3 years after retransplantation. This unique observation suggests that retransplantation of patients with previous posttransplantation KS is possible.

Background: The aim of this study was to compare the efficacy and safety of induction treatment with antithymocyte globulins (ATG) followed by tacrolimus therapy with immediate tacrolimus therapy in renal transplant recipients., Methods: This 12-month, open, prospective study was conducted in 15 centers in France and 1 center in Belgium; 309 patients were randomized to receive either induction therapy with ATG (n=151) followed by initiation of tacrolimus on day 9 or immediate tacrolimus-based triple therapy (n=158). In both study arms, the initial daily tacrolimus dose was 0.2 mg/kg. Steroid boluses were given in the first 2 days and tapered thereafter from 20 mg/day to 5 mg/day. Azathioprine was administered at 1-2 mg/kg per day., Results: At month 12, biopsy-confirmed acute rejections were reported for 15.2% (induction) and 30.4% (noninduction) of patients (P=0.001). The incidence of steroid-sensitive acute rejections was 7.9% (induction) and 22.2% (noninduction)(P=0.001). Steroid-resistant acute rejections were reported for 8.6% (induction) and 8.9% (noninduction) of patients. A total of nine patients died. Patient survival and graft survival at month 12 was similar in both treatment groups (97.4% vs. 96.8% and 92.1% vs. 91.1%, respectively). Statistically significant differences in the incidence of adverse events were found for cytomegalovirus (CMV) infection (induction, 32.5% vs. noninduction, 19.0%, P=0.009), leukopenia (37.3% vs. 9.5%, P<0.001), fever (25.2% vs. 10.1%, P=0.001), herpes simplex (17.9% vs. 5.7%, P=0.001), and thrombocytopenia (11.3% vs. 3.2%, P=0.007). In the induction group, serum sickness was observed in 10.6% of patients. The incidence of new onset diabetes mellitus was 3.4% (induction) and 4.5% (noninduction)., Conclusion: Low incidences of acute rejection were found in both treatment arms. Induction treatment with ATG has the advantage of a lower incidence of acute rejection, but it significantly increases adverse events, particularly CMV infection.

Background: Second-set rejection is generally regarded as a phenomenon mainly mediated by humoral cytotoxic antibodies, although a few discordant data have been presented. In the reported experiments, we have taken advantage of the absence of production of specific cytotoxic alloantibodies contrasting with the normal development of transplantation cellular immunity, in two murine models: chimeric mice and RAG mice., Methods: Chimeras (BALB/c-->CBA) were obtained by transplantation of 2x10(7) fetal liver cells from BALB/c (H-2d) mice to lethally irradiated CBA (H-2k) mice. After hyperimmunization with third-party C57/ BL6 (B6) (H-2b) skin transplants and with injections of 2x10(7) B6 spleen cells, antibody production, and skin graft survival were analyzed. To identify further the factors or cells responsible for accelerated rejection of B6 skin transplants in hyperimmunized chimeras, transfer experiments were carried out involving the injection of serum, whole spleen cells, spleen T cells, spleen CD8+ T cells or spleen CD4+ T cells from chimeras into BALB/c mice that had received 6 Gy irradiation. The recipient mice were then grafted with B6 skin. Similarly, the immunodeficient RAG mice were used to construct a model of recipient animals with anti-H-2d hyperimmunized B6 T cells in the total absence of antibody., Results: In chimeras, anti-B6 cytotoxic antibodies were not detectable in any of hyperimmunized chimeric mice, yet accelerated rejection of B6 skin transplant occurred: a graft survival of 8.6+/-0.5 days (d), comparable to 8.9+/-0.8 d survival in CBA control mice subjected to the same hyperimmunization procedure, and significantly shorter than that in nonhyperimmunized (BALB/c-->CBA) chimeras (11.6+/-0.5 d) or in non-hyperimmunized CBA control mice (12.1+/-0.6 d). High titers of anti-B6 cytotoxic antibodies were present in the serum of hyperimmunized CBA control mice. In transfer experiments, the graft survival was over 14 d in mice treated with irradiation alone, with irradiation + serum or with irradiation + CD4+ T cells. It was significantly shorter in mice treated with irradiation + whole spleen cells, with irradiation + T cells or with irradiation + CD8+ T cells (8.9+/-0.8 d). Similarly, in immunodeficient RAG mice, reconstitution of the T cell compartment with T cells from hyperimmunized B6 mice led to accelerated rejection of BALB/c skin allografts (11.4+/-1.1 d vs. 18.8+/-0.8 d when T cells were provided by nonimmunized mice). In a second transfer of cells from these reconstituted RAG mice into naive RAG mice, CD8+ T cells were shown to induce accelerated rejection of skin allografts (12.0+/-0.6 d) whereas CD4+ T cells were much less efficient (16.5+/-0.1 d)., Conclusion: These data indicate that T cells, and especially the CD8+ subset, can be responsible for second-set rejection in the absence of anti-donor antibodies in chimeric and RAG mouse models. These sensitized CD8+ T cells are also likely to play an important role in normal mice, in addition to that of cytotoxic antibodies.

Background: Intestinal microsporidiosis is a major cause of chronic diarrhea and malabsorption in patients with human immunodeficiency virus. Its occurrence in transplant recipients has exceptionally been reported to date., Methods: We report what we believe are the first two cases of intestinal microsporidiosis in renal transplant recipients. The patients were treated with mycophenolate mofetil., Results: The clinical presentation was chronic diarrhea with massive weight loss. Stool analysis revealed microsporidian spores, identified as Enterocytozoon bieneusi spores by polymerase chain reaction. The onset of this opportunistic infection in these two patients is believed to be secondary to an increase in immunosuppression after azathioprine replacement by mycophenolate mofetil. The withdrawal of mycophenolate mofetil led to clinical recovery., Conclusion: The incidence of microsporidiosis will probably increase in transplant recipients treated with powerful immunosuppressants. Therefore, we recommend a systematic search for microsporidian spores in stool specimens in cases of unexplained diarrhea in these patients.

Background: Sirolimus (rapamycin) is a potent immunosuppressant with a mechanism of action different from cyclosporine (CsA) or tacrolimus., Methods: In 11 European centers, first cadaveric renal allograft recipients were randomized to CsA (n=42) or sirolimus (n=41). Dosing of these agents was concentration-controlled and open-labeled. All patients received corticosteroids and azathioprine., Results: At 12 months, graft survival (98% sirolimus vs. 90% CsA), patient survival (100% vs. 98%), and incidence of biopsy-confirmed acute rejection (41% vs. 38%) were similar. Serum creatinine was lower with sirolimus, significantly (P< or =0.05) so at 3 and 4 months, and serum uric acid and magnesium were normal. Laboratory abnormalities reported significantly more often with sirolimus included hypertriglyceridemia (51% vs. 12%), hypercholesterolemia (44% vs. 14%), thrombocytopenia (37% vs. 0%), leukopenia (39% vs. 14%), and, of lesser importance, increased liver enzymes and hypokalemia. These abnormalities improved 2 months after transplantation when the sirolimus target trough level was lowered from 30 to 15 ng/ml. Occurrence of cytomegalovirus was comparable (14% vs. 12%); incidences of herpes simplex (24% vs. 10%, P=0.08) and pneumonia (17% vs. 2%, P=0.03) were higher with sirolimus. No gingival hyperplasia was seen with sirolimus, tremor was rare, and hypertension was less frequent (17% vs. 33%). Two malignancies were observed with CsA and none with sirolimus., Conclusions: Results at 12 months suggest that sirolimus can be used as base therapy in the prophylaxis of acute renal transplant rejection, and has a safety profile that differs from CsA.

The cholesterol storage disease (CSD) BALB/c mouse represents a model of the Niemann-Pick type C (NPC) disease. It is characterized by the accumulation of unesterified cholesterol within various tissues, resulting in fatal neurological lesions. Transplantation of 6x10(6) fetal liver cells from normal allogeneic CBA mice into lethally irradiated CSD mice led to reconstitution of the recipient mice with donor cells. As a result of this stable chimerism, deposition of lipids in tissues was decreased, neuropathy was prevented, and survival was significantly prolonged (over 190 days on average in transplanted mice versus 70 days in untreated mice). Foamy cells containing unesterified cholesterol, observed by filipin staining, were numerous in most tissues from untreated CSD mice; they were significantly fewer in CSD mice treated with fetal liver transplantation at the age of 36-45 days.

Hodgkin's disease (HD) has seldom been reported after transplantation. Epstein-Barr virus (EBV) is present in about 50% of Reed-Sternberg cells in HD developing in immunocompetent individuals, but is more frequently found in HD of acquired immune deficiency syndrome patients. We report 7 cases of HD that occurred in transplant recipients. Clinical and pathological data and studies of EBV reveal specific features of HD after transplantation. Six patients received kidney transplants and 1 patient received combined kidney and pancreas transplantation. Immunosuppressive therapy consisted of cyclosporine, steroids, azathioprine, and antilymphocyte globulins. One patient received, in addition, anti-CD3 mAb therapy and an EBV+ B cell lymphoma developed. Retrospective EBV serological data from patients were collected. Tumors were classified according to pathology. EBV studies were conducted by immunohistochemical methods with monoclonal antibodies to EBV-latent membrane protein (LMP) or EBV-nuclear antigen 2 (EBNA2), and by in situ hybridization for latent nuclear EBV-early RNAs (EBERs). The mean lapse of time between transplantation and HD was 49 months. Six patients presented with enlarged lymph nodes and 1 patient presented with liver involvement. HD was classified as IA in 2 patients, IIA in 3 patients, IIIB in 1 patient, and IVB in 1 patient. Four patients had primary EBV infection after graft, before HD, and the others reactivated latent EBV infection. Histological subtypes were mixed cellularity in 6 cases and lymphocytic depletion in 1 case. Latent EBV infection was detected with EBERs in all tumors. Reed-Sternberg cells expressed LMP, and were negative for EBNA2 expression. Six patients were treated: 2 patients at stage I received radiotherapy, and relapsed within 1 year with a more advanced stage of HD; chemotherapy was indicated as primary therapy in 5 patients, and as salvage therapy in 2 patients; it was associated with radiotherapy in 4 patients. Immunosuppressive therapy was reduced in all patients. Four patients were alive and in complete remission 18, 25, 31, and 67 months after chemotherapy, with a functioning graft in 3 patients. Two patients died of infection. Mixed cellularity is the most frequent histological subtype observed in HD occurring in transplant patients. EBV is present in all Reed-Sternberg cells. Posttransplant HD shows similarities with human immunodeficiency virus-associated HD. These facts argue for a role of EBV infection and immunosuppression in the progression of HD after transplantation.

The exact incidence of recurrence of membranous nephropathy (MN) after renal transplantation is not well documented because of the limited number of series involving a small number of patients. The aim of this study was to assess the incidence of MN recurrence in our population of renal transplant patients, to identify the risk factors associated with the recurrence, and to analyze the influence of the recurrence on graft and patient survival rates. The recurrence was defined as biopsy-proven MN on the renal graft in a patient whose original disease was MN. Among 1614 consecutive renal transplantations performed from January 1, 1980, to June 1, 1993, the incidence of recurrence was 26.3%, i.e., 5 recurrences out of 19 transplantations. We were unable to show pretransplant epidemiological, immunological, and therapeutic factors associated with recurrence. The HLA DR3 allele was present in 2 patients with recurrence (40%), compared with 3 patients without recurrence (21.4%). The early use of cyclosporine was not associated with a decreased prevalence of MN recurrence. Graft survival was not influenced by the recurrence. Three lymphomas were observed in the 19 transplanted patients with MN as causal nephropathy.

IFN-gamma and IL-10 secretion by sorted T cell subsets of irreversibly rejected kidney graft-infiltrating cells (GIC) and normal PBMC was studied by ELISPOT. The low spontaneous frequency of IFN-gamma-producing cells (IFN-gamma-PC) was strongly increased by anti-CD3 activation within unsorted, CD3+CD4+, and CD3+CD4- subsets of GIC and PBMC. In contrast with PBMC, IL-10-PC from GIC were at higher frequency within CD4+ cells than among CD4- ones (P < 0.03). Four kidneys removed after 3.7 +/- 0.8 months showed acute vascular rejection, high frequency of activated CD4+ IL-10-PC (118 +/- 68 per 10(4) cells), and high percentage of anti-class II antibody reactivity (87.6 +/- 6.3%). In contrast, four patients with kidneys removed later (53.7 +/- 1.6 months, P = 0.02) displayed chronic rejection with superimposed acute cellular rejection, low frequency of CD4+ IL-10-PC (7.0 +/- 3.0 per 10(4) cells, P = 0.02), and low percentage of anti-class II antibody reactivity (12.9 +/- 6.1%, P = 0.02). Thus, accelerated vascular rejection appears to be associated with preferential production of IL-10 by activated CD4+ GIC, which may act by shifting the effector arms of alloreaction toward humoral responses.

Recently, Clayberger et al. demonstrated that ALLOTRAP, small synthetic peptides derived from a conserved region of the alpha 1 helix of certain HLA class I molecules, inhibited human CTL responses in vitro. In rats, ALLOTRAP 07 therapy combined with a subtherapeutic dose of cyclosporine led to the permanent acceptance of heart allografts. In the present study, the effect of ALLOTRAP on the survival of skin allografts in mice was studied. The tail skin of male C57B1/6 (H-2b) mice was grafted on the back of male CBA (H-2k) recipients. In untreated animals, the skin graft was rejected after 11.6 +/- 1.13 days (MST +/- SD). Cyclosporine administered orally for 5 days after transplantation prolonged graft survival to 13.1 +/- 2.13 days. ALLOTRAP 2702 prolonged graft survival to 16.57 +/- 2.15 days when administered orally for five days posttransplantation and to 18.86 +/- 0.38 when administered intraperitoneally until rejection. Thus, ALLOTRAP peptides derived from human MHC class I sequences, in addition to inhibiting human T cell responses in vitro, also prolong allograft survival in rats and mice.

Clonal deletion of self-antigen-reactive T cells is known to be a dominant mechanism for tolerance induction in animals with a normal immune system. This phenomenon is mediated intrathymically by macrophages and dendritic cells. Some recent data have shown that tolerance to antigens expressed on radio-resistant thymic stromal cells results in clonal anergy. This report considers tolerance to host antigens in murine H-2-incompatible chimeras (H-2d-->H-2k) where thymic stromal cells remained of the host origin while virtually all lymphoid cells were replaced by donor H-2d cells. To assess the mechanism responsible for donor-to-host tolerance induction and the possible role of tolerogens in this process, we transferred (H-2d-->H-2k) chimeric lymphoid cells into lethally irradiated H-2d mice (a murine environment free of host H-2k antigens). Engrafted chimeric cells restored immunocompetence of secondary recipients without inducing a graft-versus-host reaction. H-2k skin test-grafts performed four weeks later were acutely rejected (median survival time = 9 days versus 11 days in controls). These results indicate that (A) donor-type lymphocytes reactive to host antigens in (H-2d-->H-2k) chimeras are not deleted during tolerance induction; (B) the continuous presence of the H-2k tolerogens appears to be necessary for the maintenance of nonreactivity to these tolerogens; (C) the anamnestic-like response to the H-2k skin grafts suggests that, during tolerance induction, anti-host (anti-H-2k) memory cells developed, an interpretation consistent with the concept that tolerance can result from a powerful immune response.

Second-set rejection is generally considered to be mediated by cytotoxic humoral antibodies. A few discordant data have been reported, however. To address this question, we have taken advantage of a model in which specific cytotoxic alloantibodies are not produced although transplantation cellular immunity develops. Following a transplant of allogeneic stem cells from fetal liver, chimeric mice (BALB/c-->CBA--i.e., H-2d-->H-2k) were obtained; virtually all peripheral blood lymphocytes and spleen cells were of BALB/c donor origin. Anti-sheep red blood cell humoral response was present, although significantly lower in chimeras than in controls. These allochimeras were hyperimmunized by skin grafts and injections of spleen cells. The survival of skin grafts and the production of antibodies were then analyzed. When hyperimmunized against a third party, B6 (H-2b), chimeric mice were not able to raise a detectable humoral response involving anti-B6 cytotoxic antibodies, yet they rejected B6 skin allografts in an accelerated fashion (8.44 +/- 0.17 days). Control CBA mice rejecting second-set B6 skin grafts within the same delay developed high-titer, specific cytotoxic antisera (mean titer = 140). These data show that cytotoxic allospecific antibodies are not indispensable in the development of second-set accelerated rejection of skin allografts.

The study aimed at analyzing the role of CMV infection as a risk factor for rejection occurring after CMV infection because of the clinical consequences of the prevention of CMV infection that might lead to the decrease in rejection episodes. Two hundred forty-two consecutive renal transplant patients were prospectively checked for the occurrence of CMV infection. CMV infection was defined virologically by a positive viremia or/and a positive viruria or/and a seroconversion or/and a significant rise of the anti-CMV antibody titers. Viremia, viruria, and serology were performed weekly for the first month and then at day 90, day 180, and every 6 months, and moreover if clinical symptoms related to a viral infection occurred. Rejection episode was defined by a creatininemia rise of 25%, after cyclosporine nephrotoxicity and urological complications had been discarded, and by the response to the antirejection therapy, steroids, or OKT3 in case of steroid-resistant rejection. The outcome factor was rejection episode occurring from day 4 after the diagnosis of CMV infection. A patient undergoing "a rejection episode after CMV infection" could also be exposed to other potential confounding factors that can be considered as risk factors of rejection among our patients. Rejection occurring before CMV infection was the main factor because it was linked both to CMV infection itself and to "rejection after." Thus infected and noninfected patients were randomly paired off. To the noninfected patient of the pair was attributed the date of a fictitious CMV infection that was the date of the CMV infection of the infected member of the pair. Therefore, "rejection after" and "rejection before" were defined in infected and noninfected patients of the pair according to the time of onset of CMV infection of the infected member of the pair. The incidence of CMV infection was 65%, 157 of the 242 patients were infected, and 85 not infected. Thus 85 pairs of infected-noninfected patients were studied. The incidence of "rejection after" the diagnosis of CMV infection was significantly higher in the group of patients with CMV infection: 45% among infected (38/85) versus 10.60% among noninfected (9/85) (P < 0.0001). Among the 85 pairs, 48 pairs were concordant in which patient of the pair evinced the same outcome factor: 43 showed no rejection after, and 5 showed one.(ABSTRACT TRUNCATED AT 400 WORDS)

The frequency of isolated low-density graft-infiltrating cells (GIC) secreting IFN-gamma, IL-6, and IL-10 was studied in 8 cases of irreversible rejection of human renal allografts, using ELISA and SPOT-forming cells (ELISPOT) assays. The GIC were mostly CD8+ T cells, although CD4+ T cells, B cells, and macrophages could also be detected. On the average, in 10(6) cells, 189 secreted IFN-gamma, 747 IL-10, and 17114 IL-6. Culture of GIC in the presence of IL-2 resulted in an increase in the frequency of IFN-gamma-producing cells (IFN-gamma-PC), in a dose-dependent manner, with an optimal 6.5-fold increase at 50 U/ml. In contrast, 25 U/ml IL-4 decreased the frequency of spontaneous and IL-2-induced IFN-gamma-PC by 71.3% and 52.8%, respectively. Furthermore, IL-4 reduced the frequency of IL-6-PC (56.8%). By this new approach to graft rejection, it becomes easier to determine cytokine profiles within an allograft and to study their modulation by different agents. It could be a useful model of study for the development of new treatment.

The role of platelet transfusion as a preparative method for kidney transplantation is still a matter of debate. Two groups of 28 male patients transplanted between 1983 and 1988, paired for age, date of transplant, absence of anti-HLA antibody and immunosuppressive therapy have been compared. Group I was given 5 purified platelet transfusions at 1-week intervals before transplantation. Each transfusion contained 7.6 x 10(6) platelets contaminated by less than 1 leukocyte in 10(5) platelets. Group II received from 3 to 5 whole blood transfusions. In all cases it was a first transplant from cadaveric donors and previously untransfused patients before entering the protocol. No patient in group I developed cytotoxic antibodies. Acute tubular necrosis occurred with the same incidence in group I and in group II but was more severe and longer in group I, requiring hemodialysis in 62.5% and only 22% in group II. ATN was significantly associated with graft loss in group I (P less than 0.05). The total number of rejections and the number of patients undergoing rejection were not significantly different in both groups. However, the intensity of rejection was significantly higher in group I with 41% (21/51) of severe or irreversible rejections versus 9/46 (19.5%) in group II (P less than 0.05). The first rejection occurred significantly earlier in group I than in group II since 75% of the first rejection episodes occurred in the first 10 days versus 38% in group II (P less than 0.02) with a mean delay of 12.8 +/- 3.2 and 19.10 +/- 3.3 days, respectively. Although platelet transfusions are devoid of leukocytes the incidence of CMV infection was not significantly different in both groups: 57% in group I and 68% in group II. Purified platelet transfusions did not induce humoral immunization but lack of sensitization does not imply indefinite graft prolongation. Because platelets do not carry class II antigens, purified platelets transfusions represent a useful model to analyze the role of class I antigens alone in the induction of unresponsiveness in organ transplantation.

We have investigated the metabolic effects of segmental (neoprene-injected) pancreas transplantation versus whole (enteric-diverted) pancreas transplantation. Seventeen uremic insulin-dependent diabetes mellitus (IDDM) patients received a simultaneous pancreaticorenal transplant: in a prospective, randomized study, 9 patients received a segmental neoprene-injected graft (group A) while 8 patients received a total pancreaticoduodenal graft, with enteric diversion (group B). The immunosuppressive therapy was based on ALG, CsA, azathioprine, and steroids. Three months after surgery, patients were submitted to the following metabolic investigation: i.v. and oral glucose tolerance tests, Hba1, i.v. arginine test, and a 24-hr metabolic profile. The OGTT, HbA1, and metabolic profile were repeated 12 and 24 months after transplantation. At 3 months after transplantation, the OGTT showed delayed insulin secretion and higher blood glucose levels in group A. Serum insulin levels after IVGTT or arginine were higher in group B than in group A. OGTT at 12 and 24 months were unchanged in group B, while in group A a higher incidence of impaired glucose tolerance (IGT) and diabetes mellitus response were observed. HbA1 and blood glucose levels during the 24-hr profile showed good metabolic control in both groups at 3, 12, and 24 months. We can conclude that both the segmental and total pancreas transplantation restore a good metabolic control in IDDM patients, though a higher incidence of IGT and DM responses were observed after OGTT in the patients receiving a segmental graft. These abnormalities do not seem to interfere with metabolic control in everyday life. These results seem to be the consequence of the different B cell masses transplanted with these two techniques.

A potent platelet-activating factor (PAF) antagonist, RP 48740, was tested for its ability to delay acute and accelerated rejection in experimental kidney transplantation. Lewis rats (RT1(1] either nonimmunized or preimmunized against Brown Norway (BN) antigens, received allogeneic kidney transplants from BN rats (RT1n) and were bilaterally nephrectomized. Survival of transplanted animals was observed following oral treatment with RP 48740 (100 mg/kg/day). Control animals received orally methylcellulose 5% (placebo), cyclosporine (10 mg/kg/day), or CsA (10 mg/kg/day) plus RP 48740 (100 mg/kg/day). CsA prolonged rat survival in both rejection models. RP 48740 induced prolongation of survival in preimmunized rats and, to a lesser but significant degree, in nonimmunized animals. Although treatment with CsA plus RP 48740 was efficient in acute rejection, it induced no significant increase of survival in preimmunized rats as compared with placebo, indicating a lack of potentiating activities between the two compounds. The pharmacokinetic study of CsA showed that this lack of efficacy of combined treatment may be interpreted as the decreased CsA bioavailability observed when the animals also received RP 48740. The demonstration that a PAF antagonist delays accelerated rejection sheds some light on the biological effects of hyperimmunization in transplantation and on the possible therapeutic approaches.

Graft failure following transplantation with T cell-depleted bone marrow or with tissue naturally devoid of T cells, such as fetal liver (FL), suggests an important role for T cells in ensuring sustained hematopoietic stem cell engraftment. Whether T cells act by eliminating host residual immune cells--or, alternatively, by helping stem cell growth and differentiation--is still to be determined. The purpose of this study was to analyze the effect of T cell supplementation to the FL graft, using a semiallogeneic murine model where the graft-versus-host reaction is absent. Lethally irradiated C3H/OuJ mice were grafted with 10(6) FL cells from (C3H/OuJ x BALB/c) F1 hybrid mice, with or without 10(6) isogeneic mature T cells (FL and FL + T groups). Recipient animals were then monitored for survival and for hematologic and immune reconstitution. Eight days postgrafting, the number of multipotent stem cells in the spleen was significantly higher in FL + T as compared with FL recipient mice. Addition of T cells to the FL graft provided a faster recovery of hematological parameters and a significant increase in short-term survival (25.5% 6 weeks of survival in the FL group, as opposed to 55.5% 6 weeks of survival in the FL + T group, P less than 0.01). By contrast, immunological functions, as assessed by mitogen responses, were quite similar in both groups of animals. Overall a promoting effect of T cells in early stem cell engraftment was clearly demonstrated in this murine model, where GVHR is absent. These results provide in vivo support for a direct T cell effect on hematopoiesis.

Pancreatic transplantation is intended to normalize carbohydrate metabolism in insulin-dependent diabetics by restoring endogenous insulin release, and it is usually performed together with kidney transplantation in patients with end-stage renal failure. A major problem in these patients is the daily control of the grafted pancreas because traditional measurements do not appear to be adequate to evaluate pancreatic function. Aiming at early detection of graft failure, we have analyzed in 8 such patients and in 20 nondiabetic kidney-grafted patients (a control group) the following variables: 24-hr glycosuria (absolute values, or values after natural logarithmic transformation) and 24-hr urinary C-peptide excretion (corrected for 24-hr urinary creatinine). These measurements, considered alone, did not detect pancreatic graft failure; for instance, glycosuria can depend on immunosuppressive steroid treatment, and it was often found even in the control group. On the contrary, the ratio Ln 24-hr glycosuria: 24-hr urinary C-peptide varied from 0.00 to 0.18 in the control group and in normally working pancreatic grafts; when the pancreatic grafts failed, however, as confirmed by arteriographic evidence, histologic findings, or dynamic endocrine tests, this ratio rose far higher than 0.18, reaching values as high as 12.2. Use of this ratio provides a simple technique for daily evaluation of pancreatic graft function and for early detection of graft failure.