Syngeneic Blood Research Articles

Adjuvant effect of allogeneic blood in vaccines against edwardsiellosis in ginbuna crucian carp Carassius auratus langsdorfii

Edwardsiella tarda (E. tarda), an intracellular pathogen, has caused severe economic losses in aquaculture. Effective vaccine development for E. tarda prevention is urgently needed. A previous study indicates that cell-mediated immunity (CMI) might play an important role in E. tarda infection. We believe that the involvement of allograft rejection and CMI has now been well documented in mammals and some fishes. However, there is still little research on the application of blood allograft rejection in vaccine development. In the current study, we investigate the immune response and vaccine effect in fish vaccinated with allogeneic blood + formalin-killed cells vaccine (FKC), allogeneic blood + phosphate-buffered saline (PBS), PBS + FKC and PBS + PBS. In the challenge test, the relative percentage survival (RPS) of the allogeneic + FKC, the allogeneic blood + PBS and the PBS + FKC group was 61.46, 35.41, and 30.63 % respectively. The up-regulated expression of Th1-related genes IFN-γ 1, IFN-γ 1rel2, IL-12p35 and T-bet suggests the protection is via CMI induction. Only in the allogeneic + FKC group, gene expression of IFN-γ 1, IL-12p35 and T-bet is significantly higher, indicating synergy between the two substances. Furthermore, among the fish injected with the allogeneic blood cells, syngeneic blood cells and PBS group, only in the fish of the allogenic blood cells injection group, did expression of IFN-γ 1, IFN-γ 2 and IFN-γ rel2 gene expression significantly increased. The results indicate that the rejection was induced by allogeneic components. Thus, our findings might provide essential information and insights into vaccine development in aquaculture.

Therapeutic application of recombinant human ADAMTS-13 improves shock reversal and coagulation status in a trauma hemorrhage and transfusion rat model

IntroductionIn hemorrhaging trauma patients, the endothelium is activated, resulting in excessive endothelial synthesis of von Willebrand Factor (vWF), which may enhance micro-thrombi formation, resulting in obstruction of the microcirculation and endothelial injury, aggravating bleeding, as well as contributing to organ failure. Under normal conditions, vWF is cleaved by the metalloprotease ADAMTS-13. After trauma, ADAMTS-13 levels are reduced.ObjectivesTo assess whether recombinant human ADAMTS-13 inhibits endothelial injury and organ failure in a rat trauma-transfusion model.MethodsBlood products were prepared from syngeneic rat blood according to blood bank standards. Polytrauma was induced in rats by crush injury to the intestines and liver and by fracture of the femur. The rats were hemorrhaged until a mean arterial pressure (MAP) of 40 mmHg was reached. Rats were randomized to receive transfusion of RBCs, FFPs, and platelets in a 1:1:1 ratio to achieve a MAP of 70 mmHg, with or without the addition of ADAMTS-13 (50 μg/kg). Blood samples were assessed for biochemistry and rotational thromboelastometry (ROTEM). Syndecan-1 and VE-cadherin levels were measured as a reflection of endothelial integrity. The amount of leakage of dextran-FITC from the vascular system to the parenchyma in lungs was quantified. To assess inflammation, IL-6 and IL-8 levels were determined. Organ damage was assessed by histopathology.ResultsAll rats were severely shocked, with no significant differences in shock parameters between groups. Rats treated with ADAMTS-13 showed signs of a more effective shock reversal (higher blood pressure, lower lactate levels) compared to controls. Also, ROTEM parameters of clot formation in rats receiving ADAMTS-13 improved compared to controls, which was mainly platelet-dependent. Syndecan-1 levels relative to baseline trended to be lower in ADAMTS-13 treated rats compared to controls (107 vs 149%, p = 0.08). ADAMTS-13 reduced albuminuria (1.7 vs 4.4 g/L, p < 0.01) and organ-specific inflammation (pulmonary IL-6 243 vs 369 pg/mL, p = 0.08; splenic IL-6 253 vs 307, p = 0.03) compared to controls, but did not improve histopathological scores.ConclusionsThe use of ADAMTS-13 in a rat trauma-transfusion model improves parameters of shock, platelet-driven coagulation, endothelial damage, and organ inflammation. These results suggest that ADAMTS-13 is important in mediating outcome of trauma. Whether ADAMTS-13 can be used as a therapeutic adjunct to treat bleeding trauma patients remains to be determined.

Preterm intraventricular hemorrhage in vitro: modeling the cytopathology of the ventricular zone

BackgroundSevere intraventricular hemorrhage (IVH) is one of the most devastating neurological complications in preterm infants, with the majority suffering long-term neurological morbidity and up to 50% developing post-hemorrhagic hydrocephalus (PHH). Despite the importance of this disease, its cytopathological mechanisms are not well known. An in vitro model of IVH is required to investigate the effects of blood and its components on the developing ventricular zone (VZ) and its stem cell niche. To address this need, we developed a protocol from our accepted in vitro model to mimic the cytopathological conditions of IVH in the preterm infant.MethodsMaturing neuroepithelial cells from the VZ were harvested from the entire lateral ventricles of wild type C57BL/6 mice at 1–4 days of age and expanded in proliferation media for 3–5 days. At confluence, cells were re-plated onto 24-well plates in differentiation media to generate ependymal cells (EC). At approximately 3–5 days, which corresponded to the onset of EC differentiation based on the appearance of multiciliated cells, phosphate-buffered saline for controls or syngeneic whole blood for IVH was added to the EC surface. The cells were examined for the expression of EC markers of differentiation and maturation to qualitatively and quantitatively assess the effect of blood exposure on VZ transition from neuroepithelial cells to EC.DiscussionThis protocol will allow investigators to test cytopathological mechanisms contributing to the pathology of IVH with high temporal resolution and query the impact of injury to the maturation of the VZ. This technique recapitulates features of normal maturation of the VZ in vitro, offering the capacity to investigate the developmental features of VZ biogenesis.

Blood Exposure Causes Ventricular Zone Disruption and Glial Activation In Vitro.

Intraventricular hemorrhage (IVH) is the most common cause of pediatric hydrocephalus in North America but remains poorly understood. Cell junction-mediated ventricular zone (VZ) disruption and astrogliosis are associated with the pathogenesis of congenital, nonhemorrhagic hydrocephalus. Recently, our group demonstrated that VZ disruption is also present in preterm infants with IVH. On the basis of this observation, we hypothesized that blood triggers the loss of VZ cell junction integrity and related cytopathology. In order to test this hypothesis, we developed an in vitro model of IVH by applying syngeneic blood to cultured VZ cells obtained from newborn mice. Following blood treatment, cells were assayed for N-cadherin-dependent adherens junctions, ciliated ependymal cells, and markers of glial activation using immunohistochemistry and immunoblotting. After 24-48 hours of exposure to blood, VZ cell junctions were disrupted as determined by a significant reduction in N-cadherin expression (p < 0.05). This was also associated with significant decrease in multiciliated cells and increase in glial fibrillary acid protein-expressing cells (p < 0.05). These observations suggest that, in vitro, blood triggers VZ cell loss and glial activation in a pattern that mirrors the cytopathology of human IVH and supports the relevance of this in vitro model to define injury mechanisms.

Immunomodulatory Effects of Blood Transfusion on Tumor Size, Metastasis, and Survival in Experimental Fibrosarcoma.

In spite of efforts, blood transfusion is still accompanied with adverse effects such as transfusion-related immunomodulation (TRIM). The current study aimed to evaluate the effects of allogeneic, syngeneic, fresh and storage blood transfusion on the growth and metastasis of tumors and survival in fibrosarcoma bearing BALB/c mice. Twenty-five BALB/c mice were grouped into five groups of equal size. All groups were injected 1.2 × 106 WEHI-164 cells subcutaneously to induce fibrosarcoma tumor. After expansion of the tumor, in four groups (except for the control group), hemorrhage-induced anemia was developed. Twenty-four hours later, blood deficit was replaced by fresh allogeneic, storage allogeneic, fresh syngeneic and storage syngeneic blood transfusion, respectively. After a blood transfusion, for 13days, the tumor size and survival of the mice were evaluated. In the day 20, the mice were sacrificed and their spleen tissues were evaluated for TRIM induced metastasis. Tumor size increase in the groups that received allogeneic (fresh and storage) and storage syngeneic blood transfusion was significantly higher than the control group (P value < 0.05). However, no significant difference was present in survival between the experiment groups and the control group. There was no metastasis in none of groups at the end of the study. Allogeneic and storage blood transfusion could have immunomodulatory effects such as increased tumor size. However, it seems that fresh and syngeneic blood transfusion have no effects on tumor growth in fibrosarcoma bearing mice. Further evidence may prove that more attention is warranted in blood transfusion into cancer cases.

Tracking Syngeneic Leukocytes after Transfusion of Non-leukoreduced Blood in a Murine Model

Objective: Several Western European countries and Canada have introduced white blood cell reduction as a universal standard to prevent potential adverse effects of allogeneic blood transfusions. However, there is an ongoing controversy regarding its appropriateness in other countries such as North America. We were interested in the whereabouts of leukocytes following whole blood transfusion in mice to evaluate their potential sites of (adverse) action. Materials and methods: Wildtype C57BL/6 were transfused with non-leukoreduced blood from enhanced green fluorescent protein transgenic C57BL/6-Tg(CAGEGFP) 1 Osb/J mice. Cells were tracked on day 3 and day 5 after transfusion by flow cytometry. Results: Enhanced green fluorescent protein-labeled leukocytes were found in the blood circulation, the myocardium, bone marrow and lung tissue up until day 5, but not in the kidney, the liver or the spleen. Myeloperoxidase activity in the lungs was significantly higher on day 5 when compared to control animals (0.09 ± 0.01% vs. 0.26 ± 0.08%, p=0.047). There was no increase in cytokines. Conclusion: Syngeneic white blood cells survive in the recipient of non-leukoreduced red blood cell units. They circulate in the blood stream and can be found in the bone marrow and the lungs up to five days after transfusion.

Syngeneic Blood and Marrow Transplantation: A Report of 94 Cases From Chinese Society of Blood and Marrow Transplantation (CSBMT).

Abstract 4295Syngeneic blood and marrow transplantation (BMT) has been applied in the treatment of many malignant or nonmalignant hematologic disorders with no or minimal and transient graft-versus-host disease (GVHD), much less transplant-related mortality (TRM) in contrast to allogeneic BMT, and lower relapse rate compared with autologous BMT. However, limited data in a single BMT center is not sufficient for statistical analysis. To evaluate the clinical outcomes of syngeneic BMT, CSBMT has performed a cooperative survey among BMT centers in mainland, Taiwan, and Hong Kong. From January 1964 to May 2009, 94 transplants from syngeneic donors have been performed in 32 BMT centers. The median age was 20 (1.5 to 51) years old. The diagnosis included AML (29 cases), SAA (26 cases), ALL (17 cases), CML (12 cases), lymphoma (3 cases), MDS (4 cases), neuroblastoma (2 cases), and large granular lymphocytosis (1 case). The main conditioning regimens were CYTBI or BUCY for malignant diseases, none or CY plus ATG for SAA. Bone marrow (BM, 34) or peripheral blood (PB, 49) or both BM and PB (11) as grafts were used. Five patients (SAA 2, AML 3) underwent the same donor's syngeneic BMT twice. One patient with large granular lymphocytosis and 1 case with SAA underwent the same donor's syngeneic BMT thrice. The median follow-up time was 28 months (1 month to 45 years). The median time for white blood cells > 1.0 × 109/L, and platelets > 20 × 109/L was 11 (2-30) days, 13 (0-122) days, respectively. Two patients (2.1%) had grade I acute GVHD (aGVHD), and 4 cases (4.3%) had grade II aGVHD. However, only one patient's specimen was consulted by pathologist. All aGVHD was controlled easily with low-dose steroid. No chronic GVHD was noted. Three-year disease-free survival (DFS) for the patients with nonmalignant disorders was 88.5%. Among them, the longest survivor was living and well for 45 years after transplant. Three-year DFS for the patients with malignant diseases was 62.9%. The overall survival rates at 3 years were 87.9%, and 69.5% for nonmalignant, and malignant diseases, respectively. 22 of 94 patients died after BMT (nonmalignant 3, malignant 19). The only cause of death for the patients with nonmalignant disorders was rejection. Relapse was the main cause of death in patients with malignancies (17/19). TRM was 2.1%. In conclusion, syngeneic BMT is a safe and effective therapeutic option for both nonmalignant and malignant hematologic disorders. Syngeneic donor, if available, should be the first choice in all cases of AA and hematological malignancies in general. The longest survivor of 45 years post-BMT is presented in this series. The good results and advantage of syngeneic BMT cast light on the potential utility of stored autologous placental-cord blood which is shared by the identical twin through the same placenta. Disclosures:No relevant conflicts of interest to declare.

Composite Tissue Formation Derived Solely From a Blood Biological Matrix: A Preliminary Study

We describe the formation of a new composite tissue containing all of the cellular components of adjacent normal spinal tissue. Four millimeter gaps, surgically created at the level of T 8–T 9 in the spinal cord of 2 adult female Lewis rats, resulted in complete paralysis of the lower extremities. A biological matrix derived from previously frozen peripheral syngeneic blood was implanted into the created spinal cord defects in 2 experimental animals. Two control animals received fibrin implants not containing matrix material. The 2 experimental animals regained significant motor function of their lower extremities as compared with the control animals, over a period of 2 months. Histological analysis of the experimental implants showed a composite tissue formation consisting of neural tissue, bone, and cartilage similar in cellular content to the adjacent native tissue. Only organized blood clot was seen at the implant site of the control animals. Further studies are needed to determine if autologous blood can be used to regenerate tissues lost to disease or injury.

Consequences of blood loss on growth of artificial metastases.

Previous studies have shown that lung metastases from a nonimmunogenic sarcoma (LS175) in BN (homozygous for RTln) rats were stimulated by blood transfusions. Enhanced growth was also observed after abdominal surgery combined with allogeneic blood transfusions while syngeneic blood transfusions had no effect. These experimental findings have been confirmed in retrospective clinical studies. The allogeneic blood transfusion effect may be avoided in cancer patients by autologous blood transfusions although this implies blood donation before surgery. The aim of the present study was to investigate the effect of blood loss before surgery on formation ('take') of lung colonies, and on the outgrowth of established metastases in the BN rat model. These aspects of tumour behaviour were also investigated in rats undergoing surgery, or receiving blood transfusion, or both, after blood loss. The results indicate that blood loss has a profound stimulating effect on the growth of established metastases, but not on the 'take' of tumour cells. This stimulating effect was also present when blood loss was combined with surgery, while previously surgery alone was found to have no effect. Allogeneic and syngeneic transfusions in combination with blood loss both had a strong stimulating effect on growth of established lung metastases. The results indicate that blood loss may be an important factor in determining the outcome of metastatic growth.

Modified total body irradiation as a planned second high-dose therapy with stem cell infusion for patients with bone-based malignancies

To estimate the maximum tolerated dose of hyperfractionated total marrow irradiation (TMI) as a second consolidation after high-dose chemotherapy with autologous or syngeneic blood stem cell transfusion for patients with bone/bone marrow-based malignant disease. Fifty-seven patients aged 3-65 years (median, 45 years), including 21 with multiple myeloma, 24 with breast cancer, 10 with sarcoma, and 2 with lymphoma, were treated with 1.5 Gy administered twice daily to a total dose of 12 Gy (n = 27), 13.5 Gy (n = 12), and 15 Gy (n = 18). Median time between the 2 transplants was 105 days (range, 63-162 days). All patients engrafted neutrophils (median, Day 11; range, Day 9-23) and became platelet independent (median, Day 9; range, Day 7-36). There were 5 cases of Grade 3-4 regimen-related pulmonary toxicity, 1 at 12 Gy, and 4 at 15 Gy. Complete responses, partial responses, and stabilizations were achieved in 33%, 26%, and 41% of patients, respectively. Kaplan-Meier estimates of 5-year progression-free survival and overall survival for 56 evaluable patients are 24% and 36%, respectively. Median time of follow-up among survivors was 96 months (range, 77-136 months). Total marrow irradiation as a second myeloablative therapy is feasible. The estimated maximum tolerated dose for TMI in a tandem transplant setting was 13.5 Gy. Because 20% of patients are surviving at 8 years free of disease, further studies of TMI are warranted.

Soluble and cell-associated forms of some yet to be identified factor in transfused blood which promotes solid tumor growth in mice.

The mechanism underlying the immunomodulation caused by blood transfusion has yet to be elucidated. The aim of the present study was to determine whether the transfusion of a soluble or insoluble factor present in stored blood can induce immunomodulation, which would thereby promote solid tumor growth. C57Bl/6J mice were subcutaneously inoculated with B16-CG melanoma cells, which secrete beta-human chorionic gonadotropin (beta-hCG). Following inoculation, each of three different products of allogeneic and syngeneic blood were transfused on days 0 and 1: fresh whole blood, stored whole blood, and supernatants from the stored blood. Tumor growth was then monitored by measuring urinary beta-hCG. All mice were killed on day 15, and the tumor weight and volume were measured. Transfusion of all allogeneic blood products enhanced tumor growth, as did the stored syngeneic whole blood. Neither fresh syngeneic blood nor the supernatant from stored syngeneic blood promoted tumor growth. Although the tumors were not visually detectable until day 10 after inoculation, by day 7 the levels of urinary beta-hCG were significantly higher in the mice that received allogeneic blood supernatant than in the mice that received saline. A soluble alloantigen enhances solid tumor growth, as does an insoluble factor present in stored syngeneic whole blood. The immunomodulation associated with this factor begins to enhance tumor growth within 7 days after transfusion.

Donor-specific blood transfusion prolongs cardiac allograft survival in rats by low nitric oxide production and elevated serum levels of prostaglandin E 2

Donor-specific blood transfusion (DST) improves allograft survival, although the exact mechanism(s) is not completely understood. The purpose of this study was to determine the role of nitric oxide (NO) and prostaglandin E 2 (PGE 2) in DST-protective effects, using a rat cardiac transplantation model. Lewis rats (RT-1 1) were transfused with fully allogeneic ACI rats (RT-l a) blood (DST group) or Lewis syngeneic blood (ST) through the portal vein 7 days prior to allogeneic cardiac transplantation. Posttransplantation, aminoguanidine (AG)-treated rat received continuous intravenous infusion of AG, an inhibitor of inducible nitric oxide synthase (iNOS). The survival times of grafted hearts were 5.7±0.5, 6.8±0.8 and 9.2±1.2 days in ST, ST/AG, and DST groups ( n=6 for each group), respectively. Inhibition of iNOS in ST/AG group prolonged allograft survival, but it was shorter than that in DST rats. Serum nitrite/nitrate levels on postgrafting day 5 were significantly higher in ST than in ST/AG and DST groups, but were similar in ST/AG and DST groups. These results were confirmed by immunohistochemical staining with anti-iNOS antibody. Serum PGE 2 concentrations in DST rats were significantly higher than in ST and ST/AG groups. Our results suggest that DST prolongs graft survival by enhanced production of PGE 2 with a resultant suppression of immune activation. In addition, DST-induced prolongation of graft survival may be partially mediated by NO suppression.

The interaction between primate blood and mouse islets induces accelerated clotting with islet destruction.

Mouse islets transplanted under the renal subcapsular space of cynomolgus monkeys are subject to a form of hyperacute rejection, the mechanism of which is unclear. As islets are in contact with whole blood at the time of transplantation, the effect of platelets and the coagulation cascade on islet destruction was assessed. Coagulation was assessed using thromboelastography on citrated/recalcified human blood samples with freshly isolated C57/Bl6 mouse islets. A dynamic islet perifusion system was used to assess the effect of islets on blood cells and coagulation factors. Cytotoxicity was evaluated using (51)Cr labelled islets incubated with human blood and islet destruction was also evaluated using a histological grading system. Continuous PO(2) measurements were made in a static incubation system to assess the role of hypoxia in islet destruction. Mouse islets incubated in human blood induced accelerated coagulation and rapid consumption of platelets within 15 min. Within 1 h of incubation, 52% of mouse islets exposed to xenogeneic human blood showed features of severe damage with necrosis when compared with islets incubated in syngeneic blood. Specific lysis of the xenogeneic islets was demonstrable (Mean percentage lysis: 48%, P < 0.05 vs. control) after 4 h incubation in human blood. Oxygen levels remained constant at a level adequate to maintain islet viability in separate experiments. Mouse islets induce rapid activation of the clotting cascade and platelet consumption in vitro when exposed to human blood, which correlated with histological evidence of significant destruction demonstrable within 1 h of exposure to human or non-human primate blood. This in vitro model has features which appear to correlate with the islet destruction seen in vivo and could be a useful model for the study of the mechanisms underlying the rapid destruction of xenogeneic islets in primate recipients.

INHIBITION OF THE ALLOGRAFT RESPONSE BY DONOR SPECIFIC BLOOD TRANSFUSION: ASSOCIATION WITH REDUCED LOCAL TH1 CYTOKINES AND NITRIC OXIDE BUT ENHANCED PROSTAGLANDIN E 2 PRODUCTION1

Donor-specific blood transfusion (DST) may improve allograft survival in human and animal models, but the mechanisms for this graft protective effect are incompletely understood. The sponge matrix allograft model was used to determine if DST induces regulatory factors within the allograft. C57BL/6 (H-2b) recipients received donor-specific (DBA/2J, H-2d) or syngeneic (C57BL/6) blood 7 days before sponge matrix allograft (DBA/2J) implantation. Fourteen days postgrafting, the sponge infiltrating cells (SIC) were examined for cytotoxic T cell (CTL) and natural killer (NK) activity, and sponge exudate fluid (SEF) was assessed for nitric oxide (.N=O) and prostaglandin E2 (PGE2) content. Interleukin- (IL) 2, IL-4, IL-10, and interferon-gamma (IFN-gamma) production by SIC was also determined. Recipient splenocytes were simultaneously assessed for anti-donor cytotoxic and proliferative responses and .N=O production. SIC from mice receiving syngeneic transfusions (ST) acquired both CTL and NK activity postgrafting, with maximal activity by day 14. DST suppressed both CTL and NK activity throughout the postgrafting period. Limiting dilution analysis (LDA) of SIC to determine precursor and native CTL frequency showed significantly lower responder cell frequency after DST compared with ST. SEF .N=O levels and SIC production of IL-2 and IFN-gamma in grafted DST mice were significantly lower than in grafted mice receiving ST. No significant amounts of IL-4 and very low levels of IL-10 were produced by SIC from grafted mice after either ST or DST. Conversely, PGE2 content of sponge fluid and serum from DST mice was higher than in mice receiving ST. Antigen stimulated splenocyte proliferation and CTL development assessed by LDA were also inhibited by DST. Reduction in local TH1 cytokines, absence of detectable TH2 cytokines, with enhanced PGE2 and depressed .N=O were observed in the local graft environment after DST. These data support the hypothesis that DST induces donor-specific intragraft suppressor factors, accompanied by reduced local and systemic immune activation.

Immune response after syngeneic and allogeneic blood cell transplantation

Immune response after syngeneic and allogeneic blood cell transplantation

Liver sinusoidal lymphocytes: their immune functions

Abstract Recent studies strongly suggest that the liver plays an im portant immunoregulatory role. Ev idence of its role in general immune responsiveness originates from ob servation that, in recipients of liver grafts, the survival of other allo-grafts is significantly prolonged. The question arises as to which blood lymphocyte subsets, most likely to be responsible for this phenomenon, marginate in liver sinusoids. To study this problem, a liver ex vivo perfusion model was designed for rats. In situ W/WAG livers were wa shed clear of sinusoidal marginating cells prior to and after 1 h perfusion with syngeneic blood. The number of blood cells retained in liver sinu soids, their phenotypes, the respon siveness to mitogen (PHA, 90 μg/ ml) and cytotoxicity against YAC-1 tumour cells were examined. Our studies showed that rat liver retains in the sinusoids a population of blood cells, enriched in NK, CD8′ and MHC class II+ cells, displaying a high cytotoxic activity and low re sponsiveness to mitogen stimula tion, with a capacity of about 106 cells/g of tissue.

Influence of allogeneic blood transfusion on natural killer cell activity in burn-injured mice.

Allogeneic blood transfusion (Allo/BT) and burn injury modify the cellular immune response in patients under a variety of circumstances. We designed this study to investigate the influence of Allo/BT, burn injury, and the combination of the two on in vivo natural killer (NK) cell activity in a murine model. This study demonstrated significant enhancement of in vivo NK cell activity in noninjured BALB/c mice receiving Allo/BT from C3H mice when compared to both the control and syngeneic blood transfusion group at posttransfusion day 5. When burn-injured mice were compared to sham-stressed mice, the burn-injured mice showed significant suppression of in vivo NK cell activity. Furthermore, in this strain combination model, Allo/BT modulated the suppressive effect of burn injury on in vivo NK cell activity at posttransfusion day 5 and postburn day 7.

Liver sinusoidal lymphocytes: their immune functions.

Recent studies strongly suggest that the liver plays an important immunoregulatory role. Evidence of its role in general immune responsiveness originates from observation that, in recipients of liver grafts, the survival of other allografts is significantly prolonged. The question arises as to which blood lymphocyte subsets, most likely to be responsible for this phenomenon, marginate in liver sinusoids. To study this problem, a liver ex vivo perfusion model was designed for rats. In situ W/WAG livers were washed clear of sinusoidal marginating cells prior to and after 1 h perfusion with syngeneic blood. The number of blood cells retained in liver sinusoids, their phenotypes, the responsiveness to mitogen (PHA, 90 micrograms/ ml) and cytotoxicity against YAC-1 tumour cells were examined. Our studies showed that rat liver retains in the sinusoids a population of blood cells, enriched in NK, CD8+ and MHC class II+ cells, displaying a high cytotoxic activity and low responsiveness to mitogen stimulation, with a capacity of about 10(6) cells/g of tissue.

Post-transfusion hepatitis: impact of non-A, non-B hepatitis surrogate tests

Summary Canada has not introduced the non-A, non-B (NANB) surrogate marker tests (antibodies to hepatitis B core antigen and alanine aminotransferase) to screen donated blood. We evaluated the effect of NANB surrogate markers in reducing post-transfusion hepatitis in a prospective randomised intervention study. From 1988 to 1992, 4588 subjects were enrolled into two study groups that received allogeneic blood from which units positive for NANB surrogate markers were either withheld (n=2311) or not withheld (n=2277). We also assessed a simultaneous non-randomised cohort (n=650) of subjects who received only syngeneic blood. All subjects were followed up for 6 months and assessed for the presence of post-transfusion hepatitis due to hepatitis A, B, C, non ABC, Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Withholding of blood containing NANB surrogate positive units reduced the overall post-transfusion hepatitis rate by 40% (p=0·065) and the hepatitis C rate by 70% (p=0·05). Most of the benefit of NANB surrogate testing was due to reduced frequency of hepatitis C virus after transfusion before all donor blood was screened for anti-HCV. During this time the overall post-transfusion hepatitis rate per 1000 transfusion recipients was 20·2 in the no-withhold group compared with 5·0 in the withhold group (p=0·05), and the HCV hepatitis rate was 12·6 and 0 respectively (p=0·06). After the introduction of HCV screening, the overall post-transfusion hepatitis rates were 8·6 and 6·8 per 1000 (p=0·55) respectively. Our study indicates that screening of blood donors with the NANB surrogate markers was of value in reducing HCV infection before HCV screening began, but subsequently the value of screening cannot be clearly established.

Growth Enhancement of Established Tumors by Allogeneic Blood Transfusion in Experimental Animals and Its Amelioration by Leukodepletion: The Importance of the Timing of the Leukodepletion

We had reported previously (Blood 81:1880, 1993) that allogeneic blood transfusions (ABT) administered before the infusion of tumor cells in both inbred and outbred experimental animals promote tumor growth and that this effect can be ameliorated by leukodepletion. To better reproduce the human situation, we evaluated, in this present study, the effect of ABT in animals with established tumors using enumeration of pulmonary metastatic nodules as the end point. The role of allogeneic blood component transfusions in promoting tumor growth and the relative efficacy of prestorage versus poststorage leukodepletion of the ABT in preventing tumor growth enhancement were also evaluated. In an inbred murine animal model, C57Bl/6J mice were administered nonleukodepleted allogeneic (ABT), leukodepleted allogeneic (LD-ABT), or syngeneic (SBT) blood transfusions after the intravenous infusion of syngeneic methylcholanthrene-induced fibrosarcoma cells using two different protocols. A significant increase in the number of pulmonary nodules was observed in those mice that received ABT, in both protocols, compared to animals transfused with SBT or LD-ABT. Significantly higher numbers of pulmonary nodules were also seen in mice transfused with allogeneic buffy-coat leukocytes compared with mice that received either nonleukodepleted allogeneic plasma or LD-ABT. In an outbred animal (rabbit) model, recipient rabbits were administered either nonleukodepleted ABT, prestorage LD-ABT, poststorage LD-ABT, or SBT on days +4 and +9 after the infusion of syngeneic epithelial tumor cells. A significant increase in the number of pulmonary nodules was seen in rabbits that received nonleukodepleted ABT compared to animals transfused with SBT. Significantly lower numbers of pulmonary nodules were observed in rabbits that received prestorage LD-ABT compared to animals transfused with poststorage LD-ABT, but no significant difference was seen in rabbits that received poststorage LD-ABT compared with animals transfused with nonleukodepleted ABT. These studies show that ABT promote tumor growth of established animal tumors, that the ABT-induced tumor growth effect is related to the presence of donor allogeneic leukocytes, and that this effect can be ameliorated by prestorage leukodepletion. The present results also provide evidence for the lack of efficacy of poststorage leukodepletion in preventing ABT tumor growth promotion.(ABSTRACT TRUNCATED AT 400 WORDS)