Effect of blood transfusions on experimental pulmonary metastases in mice

Analysis of Plasma Products for Cellular Contaminants: Comparing Standard Preparation Methods

BACKGROUND

Recent reports suggest that component plasma products contain significant quantities of cellular contamination. We hypothesized that leukoreduction of whole blood before preparation of derived plasma is an effective method to prevent cellular contamination of stored plasma.

STUDY DESIGN

Samples of never-frozen liquid plasma prepared by standard methods (n = 25) were obtained from 3 regional blood centers that supply 3 major trauma centers. Samples were analyzed for leukocyte and platelet contamination by flow cytometry. To determine if leukoreduction of whole blood before centrifugation and expression of plasma prevents cellular contamination of liquid plasma, 1 site generated 6 additional units of liquid plasma from leukoreduced whole blood, which were then compared with units of liquid plasma derived by standard processing.

RESULTS

Across all centers, each unit of never-frozen liquid plasma contained a mean of 12.8 ± 3.0 million leukocytes and a mean of 4.6 ± 2 billion platelets. Introduction of whole blood leukoreduction (LR) before centrifugation and plasma extraction essentially eliminated all contaminating leukocytes (Non-LR: 12.3 ± 2.9 million vs LR: 0.05 ± 0.05 million leukocytes) and platelets (Non-LR: 4.2 ± 0.3 billion platelets vs LR: 0.00 ± 0.00 billion platelets).

CONCLUSIONS

Despite widespread belief that stored plasma is functionally acellular, testing of liquid plasma from 3 regional blood banks revealed a significant amount of previously unrecognized cellular contamination. Introduction of a leukoreduction step before whole blood centrifugation essentially eliminated detectable leukocyte and platelet contaminants from plasma. Therefore, our study highlights a straightforward and cost-effective method to eliminate cellular contamination of stored plasma.

Current research on the immunomodulatory effect of allogeneic blood transfusion

This review summarizes three aspects of current research on the immunomodulatory effect of allogeneic transfusion. Representatives of three laboratories-each of which is actively engaged in research on transfusion-induced immunomodulation-summarize their current investigative approach. First, current animal models of transfusion-induced immunomodulation are presented and research on the tumor growth-promoting effect of allogeneic transfusion is described. Second, mechanisms underlying an immunomodulatory effect of transfusion are summarized and experiments on the induction of transplant tolerance by selective introduction of donor-type MHC antigens is presented. Third, the potential clinical impact of increased infection and tumor recurrence resulting from transfusion-induced immunomodulation is assessed. The potential role of donor-derived hematopoietic stem cells is presented as an area of future investigation in the area of transfusion-induced immunomodulation.

The tumor growth-promoting effect of allogeneic blood transfusions

Over the past decade, many studies have suggested that allogeneic blood transfusions (ABT) may adversely affect a recipient. The ABT-associated deleterious effects include the development of transfusion reactions, graft-versus-host disease, alloimmunization, and immunomodulation. While the ABT-associated immunosuppressive effects might be beneficial for recipients of kidney allografts, in reducing the relapse rate in patients with Crohn's disease, and in ameliorating the rate of abortion in women with recurrent spontaneous abortions; evidence is accumulating that the immunosuppression associated to perioperative ABT might adversely affect overall prognosis in patients with a malignancy undergoing curative cancer surgery. In addition, the ABT-associated immunomodulation has been reported to be associated with an increased risk for postoperative bacterial infections. Data from both inbred and outbred experimental animal models indicate that ABT promote tumor growth. Evidence is available that this ABT-promoting tumor growth effect can be adoptively transferred to naive animals, using splenic immunocytes. Furthermore, data from the experimental animal models indicate that the ABT effect on the growth of tumors is due to the presence of the donor leukocytes in the transfused allogeneic blood, and that this deleterious effect can be ameliorated by the pre-storage leukodepletion of the allogeneic blood. Importantly, recent evidence suggests that post-storage leukodepletion is inefficacious in preventing the ABT-associated tumor growth promotion effect. While results from studies in experimental animals cannot necessarily be extrapolated to the clinical situation, these studies suggest that ABT promote tumor growth and that pre-storage leukodepletion ameliorates this effect.(ABSTRACT TRUNCATED AT 250 WORDS)

[Transfusion and cancer]

Relationship between blood transfusion and cancer is considered from five points of view: 1) The cancer patient as a blood donor. Cancer must remain a cause of exclusion from blood donation. 2) Autologous blood transfusion for cancer patients. Predeposited autologous blood transfusion is only possible for a small number of patients. Intraoperative blood salvage carries with it the risk of disseminating tumor cells. 3) History of blood transfusion and the risk of having a cancer: a) the persistence of immune alterations following blood transfusion for years might expose the patient to an increased risk of having a cancer; b) blood transfusion might carry immunosuppressive viruses, and hepatitis viruses are related to the risk of liver cancer. 4) Cancer recurrence and blood transfusion. Conclusion of most of the published studies is that blood transfusion is associated with an increased risk of recurrence of colorectal cancer. The only realistic randomized study would compare different transfusion strategies (allogenic, leukocyte poor allogenic and autologous blood transfusion) to determine which is the best for cancer patients. 5) Post-transfusion GVH in cancer patients. Some cases have recently been published. They all can be explained by a particular HLA compatibility between the recipient and one of the blood donors.

Allogeneic blood transfusion reduces murine pulmonary natural killer (NK) activity and enhances lung metastasis of a syngeneic tumour

A model was established whereby C57BL/6 (B6) blood injected i.v. into C3H mice 7 days prior to i.v. injection of syngeneic UV-2237 tumour cells significantly increased the number of pulmonary metastases counted 21 days later as compared with levels observed in mice treated with saline, C3H or NZW blood or SRBC. This regimen of B6 allogeneic blood transfusion of C3H mice also significantly depressed splenic and pulmonary NK activity as assayed by lysis of 51Cr YAC-I in vitro and by clearance of 111In YAC-I in vivo respectively. Anti-asialo GMI treatment, which depletes NK activity in vivo, and Poly I:C treatment, which enhances NK activity in vivo, were associated with significantly increased and decreased pulmonary metastasis of UV-2237, respectively, in C3H mice. Depletion of CD4+ and CD8+ T cells had no effect. Cyclophosphamide pretreatment which, among other effects, depletes NK cells, significantly increased pulmonary metastasis of UV-2237 in C3H mice. This was corrected by adoptive transfer of normal C3H spleen cells but not spleen cells from anti-asialo GMI-treated C3H mice or B6-blood-transfused C3H mice. Furthermore, a 1:1 mixture of normal C3H spleen cells with spleen cells from B6-blood-transfused C3H mice also failed to reconstitute the cyclophosphamide-pre-treated C3H mice. We conclude that allogeneic blood transfusion augments pulmonary metastasis of the UV-2237 sarcoma in C3H mice and that the mechanism involves suppression of NK activity.

Macrophage prostaglandin E2 and oxidative responses to endotoxin during immunosuppression associated with anaesthesia and transfusion

The widespread use of blood transfusion in major surgical procedures has led to concern about the immunosuppressive effect of transfusion on patients with underlying malignancy. Transfusion may also suppress the host response to infection. The cellular mechanisms of transfusion-associated immunosuppression may involve macrophage prostaglandin E2 (PGE2) in modulating the host response to cancer and infection. We previously observed that the transfusion of blood increased PGE2 production by unstimulated macrophages. To investigate this PGE2 associated immunosuppression, we studied the effect of transfusion of rats using a physiological stimulus of macrophage PGE2 production, bacterial endotoxin. In the same macrophages, we analysed intracellular oxidative activity. Both allogeneic and syngeneic blood transfusion were associated with increased PGE2 release by macrophages. This stimulation of PGE2 increased with duration of storage of blood. A similar effect of serum indicated that a humoral factor was involved. Endotoxin (50 ng/ml-500 micrograms/ml) stimulated PGE2 production in all transfused subjects. The lowest endotoxin concentration gave proportionately the greatest stimulation. Oxidative activity was down-regulated in macrophages of transfused rats, supporting an immunosuppressive role of PGE2 within the macrophage. An effect of surgery on the oxidative response was also detected.

The Immunosuppressive Aspects of Blood Transfusion

Blood transfusion is associated with immunosuppression, although the exact etiology of the immunosuppressive effect is not fully understood. The clinical significance of the immunosuppressive effect of blood transfusion has been examined in three situations: (1) studies of renal allograft survival after renal transplantation, (2) outcome studies in patients who have had surgical resection of solid cancer tumors, and (3) studies of infection rates in postoperative patients. In each scenario, the data support the conclusion that transfusion is associated with immunosuppression as manifested by increased renal allograft survival, increased recurrence and mortality rates in patients with cancer, and increased infection rates in postoperative patients who are transfused. Not all studies demonstrate an immunosuppressive effect of transfusion. There are several possible explanations for these discrepancies. First, prognostic variables other than transfusion itself account for the outcome results in these retrospective studies. Second, the extent of immunosuppression may be influenced by the type of blood product transfused, the amount transfused, and the timing of the transfusion; these factors have not been considered in all studies. For example, whole blood has been implicated as having a greater immunosuppressive effect than packed red blood cells, and many studies have shown that more than three units of packed red blood cells are necessary to affect outcome. Controlled animal studies have tested the hypothesis that transfusions increase solid tumor growth or the risk for infection. These studies have yielded conflicting results. Nevertheless, evidence that blood transfusion influences clinical outcome mitigates that a decision to transfuse must consider both risks and benefits of a transfusion; the possible consequences of immunosuppression must be included among the risks. Use of autologous blood, erythropoietin, and, in the future, synthetic hemoglobin may lead to improved outcome in patients with certain disease processes.

Effect of allogeneic blood transfusion on solid tumor growth and pulmonary metastases in mice

The effect of allogeneic blood transfusions on solid tumor growth and pulmonary metastases was examined in two different strains of mice. Recipient mice (C57B1 or DBA/2) were given transfusions from allogeneic donors (Balb/c or B6AF1, respectively). The effect of allogeneic blood transfusion on solid tumor growth (B16 in C57B1 mice and P815 in B6AF1 mice) as well as the number of pulmonary metastases (B16 in C57B1 mice) was examined utilizing inoculations of varying numbers of tumor cells. In both solid tumor models, allogeneic transfusion resulted in significant enhancement of tumor growth when smaller (1.25 x 10(5), 2.5 x 10(5)) numbers of tumor cells were inoculated into the host animal. In contrast, no effect of allogeneic transfusion on tumor growth was observed when higher (4.5 x 10(5)) numbers of tumor cells were inoculated. Similarly, increased numbers of pulmonary metastases following allogeneic blood transfusion were observed when lower numbers (1 x 10(5)) of B16 tumor cells were administered; whereas no effect was observed with higher (4.5 x 10(5)) tumor cell numbers. The data in the present study suggest that the number of tumor cells inoculated into the recipient animal has a strong bearing in the allogeneic blood-transfusion-induced tumor growth effect.

Relationship between blood transfusion and tumour behaviour

Blood transfusion results in significant alterations in some parameters of immune function. Because some human cancers appear to stimulate immune responses and may be influenced by host immunity, the possibility arises that transfusion could alter the behaviour of tumours. Experimental studies indicate that allogeneic transfusion can directly alter tumour growth in some circumstances, but at present studies of human cancers do not provide evidence of a causal association between transfusion and tumour growth.

A new rat colon cancer cell line metastasizes spontaneously: biologic characteristics and chemotherapeutic response

A new cell line (RCN-9) was established in culture from a transplantable rat colon adenocarcinoma, which was induced in the colon of a male Fischer F344 rat by subcutaneous administration of 1,2-dimethylhydrazine. When RCN-9 cells were injected subcutaneously or into the cecal subserosa of syngeneic rats, carcinomas with progressive growth were obtained and the development of lung (63.6%) and liver (40.0%) metastases, respectively, ensued. Antitumor effects of 5-fluorouracil (5-FU), adriamycin (ADM) and mitomycin C (MMC) against RCN-9 were examined in vivo and in vitro. 5-FU and ADM had antitumor effects both in vivo and in vitro; MMC had antitumor effects in vitro. These results show that the RCN-9 cell line can be used both as a model to study mechanisms of metastasis from colon carcinoma and as a model in chemotherapeutic studies of metastatic disease from colon carcinoma.