Alteration of proliferation and subtle changes of protein synthesis in autologous transplanted spleens.

In the case of massive splenic rupture, heterotopic autologous transplantation of splenic tissue into the omentum majus may be used to restore splenic function. Yet little is known about specific functions of the transplants compared to the normal spleen. The goal of this study was to get more information about immunologic functions and protein expression in splenic transplants. As an animal model we used the pig, whose splenic morphology and immunoarchitecture is similar to that of the human spleen. Histologic examination of transplants revealed structures that were comparable to normal spleens (consisting of red and white pulp and including germinal centers). Immunologic tests such as the hemolytic plaque assay and mitogen stimulation revealed that the number of plaque-forming cells was not changed significantly, but the stimulation index for T cells was drastically increased in the autotransplants. Electrophoresis and immunochemical methods showed differences in the protein patterns between both tissues. Several proteins were found to be produced only in the spleen, or were produced in much higher amounts in the spleen than in the splenic transplants. More information about these differences between spleen and splenic transplants is needed before we can recommend a general clinical application of autologous spleen transplantation.     

Intradermal cell transplantation in soluble collagen

Intradermal, as opposed to subcutaneous, cell transplantation was previously shown to be advantageous for tumor cell growth, but this site has not been used for transplantation of normal nonneoplastic cells. In preliminary experiments we found that it was difficult to control the size and shape of transplants when we injected dissociated cells intradermally. This problem was solved by placing cells in nongelled, pepsin-solubilized collagen prior to injection. This technique permitted the successful transplantation of normal bovine adrenocortical cells and of neoplastic cells (3T3 cells secreting FGF) in scid mice. Primary bovine adrenocortical cells formed functional vascularized tissue and the transplants rescued the animals from the lethal effects of adrenalectomy. The histological structure of transplant tissues resembled that previously observed when cells were transplanted in the subrenal capsule space. We also used a line of 3T3 cells that has been genetically modified to secrete a form of acidic FGF. When transplanted intradermally in collagen, they formed rapidly enlarging masses of cells that could easily be palpated beneath the skin of the animal. Intradermal injection of cells in pepsin-solubilized collagen is a simple and reliable technique for transplanting normal primary cells and preneoplastic cells. The ability to grow both types of cells in an easily accessible site allows less invasive monitoring of growth, angiogenesis, and other features of the transplant.     

Histopathology and Immunophenotype of the Spleen During Acute Antibody‐Mediated Rejection

Splenectomy has been reported to have a beneficial effect in treating Acute antibody‐mediated rejection (ABMR). This reason for this often rapid and profound beneficial effect is not readily apparent from what is known about normal splenic immunoarchitecture. While the spleen is rich in mature B cells, it has not been noted to be a repository for direct antibody‐secreting cells. We present a case of a Native American female who received a renal transplant and developed a severe episode of ABMR. The patient was initially refractory to both plasmapheresis and IVIG. The patient underwent an emergent splenectomy with almost immediate improvement in her renal function and a rapid drop in her DR51 antibodies. Immunohistochemical stains of the spleen demonstrated abundant clusters of CD138+ plasma cells (>10% CD138 cells as opposed to 1% CD138 cells as seen in traumatic controls). Though this is a single case, these findings offer a rationale for the rapid ameliorative effect of splenectomy in cases of antibody rejection. It is possible that the spleen during times of excessive antigenic stress may rapidly turn over B cells to active antibody‐secreting cells or serve as a reservoir for these cells produced at other sites.     

Apoptosis and allograft rejection in the absence of CD8+ T cells.

BACKGROUND: The requirement for cytotoxic T lymphocytes during allograft rejection is controversial. We previously demonstrated that CD8+ T cells are not necessary for allograft rejection or for the induction of apoptosis in rat small intestinal transplantation. In this study, we examined the mechanisms of apoptosis and rejection after liver transplantation in the absence of CD8+ T cells. METHODS: Either Lewis or dark agouti rat liver grafts were transplanted into Lewis recipients to create syngeneic and allogeneic combinations. CD8+ T cells were depleted in an additional allogeneic group by treatment with OX-8 mAb on day -1 and day 1 after liver transplant. RESULTS: Apoptosis and rejection were observed in both the CD8+ T cell-depleted allogeneic and allogeneic grafts by hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, and radiolabeled-annexin V in vivo imaging. Granzyme B and FasL were expressed in all allogeneic transplants, including those depleted of CD8+ T cells, indicating that a mononuclear cell other than a CD8+ T cell can be the source of these molecules during allograft rejection. Activation of the caspase cascade was detected in all rejecting allografts. Caspases 3, 8, and 9 were activated at similar significantly elevated levels in both allogeneic and CD8+ T cell-depleted liver grafts. CONCLUSION: These data indicate that in the absence of CD8+ T cells an alternative pathway, associated with granzyme B and FasL expression and activation of the caspase cascade, can mediate apoptosis and graft rejection.     

Epstein-Barr virus infection and immunity in bone marrow transplant recipients

Studies on patients for up to one year following allogeneic, HLA-matched bone marrow transplants have shown no increased incidence of salivary Epstein-Barr (EB) virus secretion and no significant rise in EB-virus-specific antibody titers. EB-virus-specific cytotoxic T cells could be detected in the peripheral blood of all patients by six months posttransplant. For up to one year posttransplantation in vitro EB virus infection of peripheral blood B lymphocytes from the majority of patients leads to an abortive infection followed by cell death, and without the establishment of continuously growing cell lines. This abnormality appeared to be due to patients' monocytes, which formed a defective feeder cell layer in culture, and it could be circumvented by culturing the EB-virus-infected B cells from patients on a feeder layer of x-irradiated adherent cells from normal peripheral blood. These findings may explain the relative lack of EB-virus-associated lymphoma seen in bone marrow transplant recipients when compared with other groups of transplant patients.     

A retrospective flow cytometric crossmatch study in transplant recipients with autoreactive lymphocytotoxic antibodies

Abstract Our previous data shows renal transplant recipients with autoreactive lymphocytotoxic antibodies to have a reduced transplant survival when compared to patients without autoantibodies. This could have been due to the presence of weak IgG antibodies inhibited by the dithiothreitol used to remove IgM antibodies in the pretransplant cytotoxicity cross-match. That possibility was investigated in a retrospective study of 52 recipients of 57 renal transplants who were recrossmatched using a more sensitive flow cytometry crossmatch (FCXM) to detect recipient IgG antibodies to donor T and/or B cell splenic lymphocytes. Fourteen of the 57 (24%) transplants failed. Six losses were within the 1st month posttransplant and four of these were immunological failures. None of the transplant failures had a positive pretransplant FCXM. These results showed that the recipients with autoantibodies did not have pretransplant IgG anti-donor antibodies. The transplant failures did not, therefore, relate to the presence of antibodies undetected by the dithiothreitol-treated cytotoxicity crossmatch.     

Immune responses to organ allografts. II. Decreased B cell responses to cardiac allografts in rats pretreated with enhancing, suppressor cell, or T lymphocyte depletion protocols.

Primarily vascularized LBN cardiac allografts transplanted to LEW rats are rejected 6 to 8 days after transplantation. Immunoperoxidase stains for cells producing immunoglobulin (Ig) demonstrate a proliferation of Ig-containing immunoblasts in the splenic red pulp (RP) and peripheral periarterial sheath (PAS) within 2 days after transplantation. These immunoblasts differentiate into plasma cells that triple the RP volume by the time of rejection. By 14 days, the plasma cells are replaced by mitotically active large and small lymphocytes with no demonstrable cytoplasmic Ig. Splenic Ig production is followed by a venous vasculitis in the graft and by the appearance of circulating cytotoxic antibodies 5 days after grafting. Three biological methods of prolonging cardiac graft survival were found to derange this sequence of immunological reactions at different stages. Enhancement by antigen and antibody pretreatment of the recipient elicited a premature production of Ig that subsided and was not reinitiated by cardiac transplantation. Transfer of suppression with thymocytes from enhanced cardiac recipients temporarily inhibited differentiation of splenic B cells into immunoblasts and plasma cells. T cell depletion by thymectomy, irradiation, and bone marrow reconstitution also decreased the plasma cell response, possibly by removing helper cells required to switch IgM production to IgG. These studies reemphasize the importance of Ig production in the complex interaction of immune reactions leading to acute rejection of organ transplants.     

Identification of Epstein-Barr virus-specific CD8+ T lymphocytes in the circulation of pediatric transplant recipients

BACKGROUND: Pediatric transplant recipients are at increased risk for Epstein Barr virus (EBV)-related B cell lymphomas. In healthy individuals, the expansion of EBV-infected B cells is controlled by CD8+ cytotoxic T cells. However, immunosuppressive therapy may compromise antiviral immunity. We identified and determined the frequency of EBV-specific T cells in the peripheral blood of pediatric transplant recipients. METHODS: HLA-B*0801 and HLA-A*0201 tetramers folded with immunodominant EBV peptides were used to detect EBV-specific CD8+ T cells by flow cytometry in peripheral blood mononuclear cells from 24 pediatric liver and kidney transplant recipients. The expression of CD38 and CD45RO on EBV-specific, tetramer-binding cells was also examined in a subset of patients by immunofluorescent staining and flow cytometry. RESULTS: Tetramer-binding CD8+ T cells were identified in 21 of 24 transplant recipients. EBV-specific CD8+ T cells were detected as early as 4 weeks after transplant in EBV seronegative patients receiving an organ from an EBV seropositive donor. The frequencies (expressed as a percentage of the CD8+ T cells) of the tetramer-binding cells were HLA-B8-RAKFKQLL (BZLF1 lytic antigen peptide) tetramer, range=0.96 to 3.94%; HLA-B8-FLRGRAYGL (EBNA3A latent antigen peptide) tetramer, range=0.03 to 0.59%; and HLA-A2-GLCTLVAML (BMLF1 lytic antigen peptide) tetramer, range=0.06 to 0.76%. The majority of tetramer reactive cells displayed an activated/memory phenotype. CONCLUSIONS: Pediatric transplant recipients receiving immunosuppression can generate EBV-specific CD8+ T cells. Phenotypic and functional analysis of tetramer cells may prove useful in defining and monitoring EBV infection in the posttransplant patient.     

B and T cell abnormalities in patients with primary IgA nephropathy

The in vitro function of B and T cells was studied in 16 patients with primary IgA nephropathy (PIgA-N). The distribution of OKT3+ cells (total peripheral T cells) and of regulatory T cell subsets (helper OKT4+ and cytotoxic/suppressor OKT8+ cells) was evaluated and a testing for 47 HLA-A, B, C, DR, and DQ antigens was carried out in the 16. B lymphocyte IgA production, after stimulation by pokeweed mitogen in the presence of T cells from normal donors treated with mitomycin C, was significantly greater in patients than in controls. T lymphocytes from patients with PIgA-N were more efficient than T cells from controls in providing IgA specific helper activity for normal B cells. The analysis of the individual data showed that the overactivity of B cells and the T cell operational dysfunction was present in about 50% of the patients and did not correlate. No numerical imbalance between T lymphocyte subsets nor any association between lymphocyte behavior, HLA antigen distribution, and a number of clinical, laboratory, and immunohistological findings was observed. Our data, therefore, suggest that PIgA-N is an immunologically heterogeneous disease and that an IgA-specific B cell overactivity and/or overall IgA-specific T cell helper activity may be present in some patients.     

Lectin-like oxidized low-density lipoprotein (LDL) receptor (LOX-1)-mediated pathway and vascular oxidative injury in older-age rat renal transplants

BACKGROUND: Older-age renal allografts are associated with inferior survival; however, the mechanisms are unclear. Reactive oxygen species participate in aging and in chronic vascular disease. We investigated how mediators of oxidative stress may increase allograft susceptibility to vascular injury. METHODS: We employed the low-responder allogeneic F344-to-Lew rat renal transplantation model. We used nonimmunosuppressed young (donors and recipients aged 12 weeks), old (donors and recipients aged 52 weeks), and old-to-young animal (donors aged 52 weeks and recipients aged 12 weeks) combinations. Grafts were transplanted after 2 hours cold preservation in University of Wisconsin solution and harvested 1, 2, 7 and 10 days later. Additionally, old animals receiving continuous 1.5 mg/kg cyclosporine (CyA) immunosuppression were included. Renal allograft pathology was scored according to Banff criteria. We studied intragraft vascular adhesion molecule-1 (VCAM-1), lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1), and hypochlorite-modified LDL expression as well as ED-1+ monocytes/macrophages and CD8+ lymphocyte infiltration. Intragraft in situ superoxide anion radical production was determined with dihydroethidium assay on cryosections. RESULTS: During the first 2 posttransplant days, old transplants demonstrated higher functional impairment and increased oxidative stress, while young transplant had higher ED-1+ monocytes/macrophage infiltration and VCAM-1 expression. The degree of VCAM-1 expression and ED-1+ monocytes/macrophage and CD8+ lymphocyte infiltration correlated at later time points directly with the transplant age. VCAM-1 and LOX-1 staining were localized predominantly on the endothelium of arterial vessels, shifting the distribution to vascular smooth muscle layer strongly dependent on donor age and the grade of vascular injury. LOX-1 staining colocalized with hypochlorite-modified epitopes in the media of injured arteries. We measured increased in situ superoxide anion radical production in corresponding areas. Immunosuppression with CyA had no protective effect on vascular injury and LOX-1 expression. CONCLUSION: Induction of LOX-1-related oxidation pathways and increased susceptibility to oxidative stress could play an important role in promoting vascular injury in old renal transplants independent of the recipient age.     

Immune cell subpopulations in regenerated splenic tissue in rats.

BACKGROUND: Asplenic patients have an increased risk of infections. Operations such as autotransplantation or splenic artery ligation have been suggested to ensure retention of functional splenic tissue after splenectomy, but their protective value is unclear. Immune responses, such as production of antibody, remain impaired in humans and animals even when such tissue is present, and phagocytosis is less efficient than by normal spleen tissue. In the present study the cellular composition of regenerated tissue is determined. METHODS: Splenic tissue was obtained from rats 6-9 months after splenic autotransplantation, splenic artery ligation or sham operation. The lymphocyte and macrophage subpopulations were labelled using a panel of monoclonal antibodies and analysed by flow cytometry. RESULTS: Both the total number of cells and the number of cells per gram of tissue were significantly reduced. There was a substantial reduction in the percentage of some of the cells examined (CD4+ and CD8+ T lymphocytes subsets), but not all (B lymphocytes, ED1+ and ED2+ macrophages, OX2+ and OX6+ cells). CONCLUSIONS: The reduction in the T lymphocyte subsets in regenerated splenic tissue compared with the normal spleen might explain the immunological dysfunction which persists after splenic autotransplantation. The reduction in the number of macrophages may be responsible for the alteration in phagocytic efficiency of regenerated splenic tissue.     

Regulation of transplant arteriosclerosis by CD25+CD4+ T cells generated to alloantigen in vivo

BACKGROUND: CD25+CD4+ regulatory T cells have been shown to suppress alloimmunity in various experimental settings. Here, we hypothesized that alloantigen-reactive regulatory T cells would reduce the severity of transplant arteriosclerosis. METHODS: CD25+CD4+ T cells from CBA mice that were pretreated with C57BL/6 (B.6) blood (donor-specific transfusion, DST) and nondepleting anti-CD4 Ab (YTS 177) were cotransferred with na?ve CBA CD25-CD4+"effector" T cells into CBA-rag-/- mice. These animals received aorta transplants from B.6 CD31-/- donors. CBA wild-type recipients of B.6 aorta grafts were pretreated with 177/DST directly. Some animals received 6x10(5) CD25+CD4+ T cells from pretreated mice to augment regulation on day -1. Grafts were harvested on day 30. RESULTS: Luminal occlusion of the graft caused by neointima formation was 29.3+/-19.4% (n=5) after transfer of effector T cells only. Co-transfer of CD25+CD4+ regulators reduced occlusion significantly (2.4+/-3.3%, n=3; P=0.009). This effect was partially abrogated in the presence of a CTLA4 blocking Ab (11.1+/-4.7%, n=4; P=0.008). Pretreating immunocompetent CBA recipients of B.6 aortic allografts with 177/DST did not reduce transplant arteriosclerosis significantly (43.0+/-15.7%, n=5 vs. 56.6+/-16.8%, n=5; 177/DST vs. controls; P=0.22). However, when pretreated primary CBA recipients received an additional transfer of 6 x 10(5) CD25+CD4+ T cells procured from other mice pretreated with 177/DST before transplantation, luminal occlusion of the graft was markedly reduced (33.0+/-7.6%, n=5; P=0.002). CONCLUSION: Regulatory T cells generated in vivo to alloantigen can prevent CD25-CD4+ T-cell-mediated transplant arteriosclerosis. In immunocompetent recipients, these cells have potential to be used as cellular immunotherapy to control transplant arteriosclerosis.     

Early passenger leukocyte migration and acute immune reactions in the rat recipient spleen during liver engraftment: with particular emphasis on donor major histocompatibility complex class II+ cells

After a short course of tacrolimus, Lewis rat liver allografts induce donor-specific nonreactivity in Brown Norway recipients that is immunosuppression-independent after 28 days. To clarify the role of donor major histocompatibility complex (MHC) class II+ cells, we investigated the migration to the recipient splenic T- and B-cell compartments of different subsets of Lewis MHC class II+ passenger leukocytes. The rise and decline of immune activation were monitored in the hepatic allograft and in the host spleen by analyses of BrdU+ (proliferating) leukocytes, TUNEL+ (apoptotic) cells, apoptosis-associated molecules, TH1/TH2 cytokine profiles, and histoimmunocytochemical examination of graft and splenic tissues. Serial flow cytometry studies during the 28-day period of drug-assisted "hepatic tolerogenesis" showed that migratory MHC class II+ cells accounted for less than half of the donor cells in the host spleen. The class II+ cells consisted mostly of B cells that homed to splenic B-cell follicles with only a sparse representation of dendritic cells that were exclusively found in the splenic periarteriolar lymphoid sheath. In parallel studies, transplantation of the less tolerogenic heart produced a diminutive version of the same events, but with far fewer donor cells in the host spleen, evidence of sustained immune activation, and the development of chronic rejection by 100 days. The data are consistent with the paradigm that migration of donor leukocytes is the prime determinant of variable tolerance induction induced by transplantation of the liver and other organs, but without regard for donor MHC class II+ expression.     

Regulatory influence of thymopentin on splenic T cell sets of thymectomized and aged mice

Thymectomy of mice aged 6-8 weeks causes a disproportion of splenic T cell sets, the Ly123 set being relatively decreased and the Ly23 set relatively increased (Ly123 decrease: Ly23 increase). A similar disproportion of splenic T cell sets was found to occur spontaneously with advancing age (12-18 months). By PA-SRBC assay, the total number of splenic Lyt+ cells is not appreciably reduced by thymectomy or by aging, but the Thy-1+ cell count falls by about 40% according to both PA-SRBC and cytotoxicity assays. Thus there is an increase in the number of Lyt+ cells expressing sub-threshold amounts of Thy-1. The following observations show that thymopentin (TP-5), a synthetic pentapeptide analogue of thymopoietin, counteracts these changes in thymectomized and aged mice. As reported previously, the capacity of C3H/HeJ female mice to reject C3H/HeJ male skin was raised by thymectomy, or with age, and treatment with TP-5 substantially normalized the rejection response. Here we correlate these findings with changes in the profile of splenic T cell sets. The splenic T cell set profile of thymectomized B6-Tlaa male and female mice was essentially restored by TP-5. The Ly123 decrease: Ly123 increase change caused by thymectomy was not associated with obviously altered proportions of Qa-1+ and Qa-1- subsets. Treatment of aged mice with TP-5 also prevented the onset of changes in splenic T cell sets that occur spontaneously with age. Thus thymectomy and aging give rise to disproportions of splenic T cell sets, and in C3H female mice to a heightened capacity for male skin rejection, both effects being largely abrogated by the TP-5 derivative of thymopoietin.     

Infiltration of activated dendritic cells and T cells in renal cell carcinoma following combined cytokine immunotherapy

OBJECTIVES: In a phase I study the feasibility, toxicity and immunological effects of peri-operative cytokine immunotherapy of renal cell carcinoma were studied. Main goals were to determine the maximal tolerable dose and detailed in situ analysis of tumor infiltrates. METHODS: Fifteen patients with renal cell carcinoma, undergoing nephrectomy, received subcutaneous immunotherapy, consisting of low-dose IL-2, IFNalpha and GM-CSF, from day -3 prior, until day +5 following surgery in a dose escalation study. Infiltrates from resected tumor tissues from patients undergoing immunotherapy or control patients that underwent nephrectomy only, were examined using quantitative immunohistological analysis and 3-color immunofluorescence staining and confocal laser scanning microscope analysis. RESULTS: Toxicity was limited and the maximal tolerable dose was established. In peripheral blood an increase was found in total lymphocytes, (activated) T cells, NK cells and monocytes. Quantitative immunohistological analysis of tumor infiltrates showed enhanced numbers of CD3+ T cells, S100+ DC, CD83+ DC and IL-2 receptor positive cells (4-fold, 2-fold, 10-fold and 20-fold, respectively, compared to controls). In treated patients preferential invasion was observed of TNFalpha positive CD8+ T cells and DC, positive for DC-SIGN (CD209), CD83, CD80, IL-12 and the DC specific chemokine, DC-CK1 (CCL18). CONCLUSIONS: These findings show increased infiltration of activated, mature DC and functionally active CD8+ T cells in renal tumors, which may suggest clinical potential of cytokine immunotherapy.     

Candidal splenic abscess in a renal transplant patient

Despite the large number of organ transplants performed yearly, to date there have been no reports of candidal splenic abscess. We describe here the first case of candidal splenic abscess in a renal transplant recipient treated successfully by splenectomy and amphotericin B. Despite a lengthy illness, the patient recovered with preservation of renal function.     

Human fetal islet transplantation in type 1 diabetics: comparison of immunological effects between multiple implantation regimens

Previous studies have suggested that the multiple transplants might be equally metabolically efficient to a single regimen for human adult islets. The aim of this study was to compare immunological and metabolic parameters after each of the two regimens of human fetal islets (HFI). Group A single transplants (n = 9) had 180 +/- 20 x 1000 HFI equivalents (IEQs) implanted via a single intramuscular injection. In group B multiple transplants (n = 8) islets were implanted by three consecutive injections of 60 +/- 10 x 1000 IEQs at 7-day intervals. We analyzed the immunological parameters of CD4/CD8 T lymphocyte ratios; islet cell antibodies (ICAs) and insulin antibodies (IAs). We estimated insulin secreting capacity (ISC) as the metabolic parameter. We observed that the CD4+/CD8+ T-cell ratio increased, peaking on day 90, in similar fashion in both groups: day -1: A = 1.18 +/- 0.03 versus B = 1.19 +/- 0.04; on day 90: A = 1.79 +/- 0.09, versus B = 1.75 +/- 0.08 (P = NS) immediately before the decrease in C-peptide levels. Thereafter the ratios rapidly decreased without statistical differences. The levels of ICAs did not change. The levels of IAs, which were increased before transplant, then decreased without statistical differences between the groups. The values of ISC increased after transplant and then decreased similar to the T-cell ratio. Our results demonstrated that regimens of multiple and single HFIs did not show differences in the kinetics of the immunological response presumably mediating graft destruction. The CD4/CD8 ratio increased as the C-peptide level decreased, peaking on day 90 at the time of a decrease in C-peptide. These results may be useful for clinical studies of HFIs for type 1 diabetic patients.