Effect of intermediate-purity factor VIII (FVIII) concentrate on lymphocyte proliferation and apoptosis: transforming growth factor-beta is a significant immunomodulatory component of FVIII

An Increased Proportion of Apoptosis in CD4⁺ T Lymphocytes Isolated from the Peripheral Blood in Patients with Stable Chronic Obstructive Pulmonary Disease

BACKGROUND

The pathophysiology of chronic obstructive pulmonary disease (COPD) includes inflammation, oxidative stress, an imbalance of proteases and antiproteases and apoptosis which has been focused on lately. Abnormal apoptotic events have been demonstrated in both epithelial and endothelial cells, as well as in inflammatory cells including neutrophils and lymphocytes in the lungs of COPD patients. An increased propensity of activated T lymphocytes to undergo apoptosis has been observed in the peripheral blood of COPD patients. Therefore, the apoptosis of T lymphocytes without activating them was investigated in this study.

METHODS

Twelve control subjects, 21 stable COPD patients and 15 exacerbated COPD patients were recruited in the study. The T lymphocytes were isolated from the peripheral blood using magnetically activated cell sorting. Apoptosis of the T lymphocytes was assessed with flow cytometry using Annexin V and 7-aminoactinomycin D. Apoptosis of T lymphocytes at 24 hours after the cell culture was measured so that the T lymphocyte apoptosis among the control and the COPD patients could be compared.

RESULTS

Stable COPD patients had increased rates of CD4⁺ T lymphocyte apoptosis at 24 hours after the cell culture, more than the CD4⁺ T lymphocyte apoptosis which appeared in the control group, while the COPD patients with acute exacerbation had an amplified response of CD4⁺ T lymphocyte apoptosis as well as of CD8⁺ T lymphocyte apoptosis at 24 hours after the cell culture.

CONCLUSION

Stable COPD patients have more apoptosis of CD4⁺ T lymphocytes, which can be associated with the pathophysiology of COPD in stable conditions.

To serve and protect: The modulatory role of von Willebrand factor on factor VIII immunogenicity

Hemophilia A is a bleeding disorder characterized by the absence or dysfunction of blood coagulation factor VIII (FVIII). Patients are treated with regular infusions of FVIII concentrate. In response to treatment, approximately 30% of patients with severe hemophilia A develop inhibitory antibodies targeting FVIII. Both patient and treatment related risk factors for inhibitor development have been described. Multiple studies comparing the immunogenicity of recombinant and plasma-derived FVIII have yielded conflicting results. The randomized controlled SIPPET (Survey of Inhibitors in Plasma-Product Exposed Toddlers) trial demonstrated an increased risk of inhibitor development of recombinant FVIII when compared to von Willebrand factor (VWF)-containing plasma-derived FVIII. Presently, it is unclear which mechanism underlies the reduced immunogenicity of plasma-derived FVIII. In this review we address the potential role of VWF on FVIII immunogenicity and we discuss how VWF affects the immune recognition, processing and presentation of FVIII. We also briefly discuss the potential impact of glycan-composition on FVIII immunogenicity. It is well established that VWF shields the uptake of FVIII by antigen presenting cells. We have recently shown that VWF binds to the surface of dendritic cells. Here, we present a novel model in which surface bound FVIII-VWF complexes regulate the internalization of FVIII. Binding of FVIII to VWF is critically dependent on sulfation of Tyr1699 (HVGS numbering) in the light chain of FVIII. Incomplete sulfation of Tyr1699 has been suggested to occur in several recombinant FVIII products resulting in a loss of VWF binding. We hypothesize that this results in alternative pathways of FVIII internalization by antigen presenting cells which are not regulated by VWF. This hypothetical mechanism may explain the reduced immunogenicity of VWF containing plasma-derived FVIII concentrates as found in the SIPPET study.

Biological considerations of plasma-derived and recombinant factor VIII immunogenicity

In hemophilia A, the most severe complication of factor VIII (FVIII) replacement therapy involves the formation of FVIII neutralizing antibodies, also known as inhibitors, in 25% to 30% of patients. This adverse event is associated with a significant increase in morbidity and economic burden, thus highlighting the need to identify methods to limit FVIII immunogenicity. Inhibitor development is regulated by a complex balance of genetic factors, such as FVIII genotype, and environmental variables, such as coexistent inflammation. One of the hypothesized risk factors of inhibitor development is the source of the FVIII concentrate, which could be either recombinant or plasma derived. Differential immunogenicity of these concentrates has been documented in several recent epidemiologic studies, thus generating significant debate within the hemophilia treatment community. To date, these discussions have been unable to reach a consensus regarding how these outcomes might be integrated into enhancing clinical care. Moreover, the biological mechanistic explanations for the observed differences are poorly understood. In this article, we complement the existing epidemiologic investigations with an overview of the range of possible biochemical and immunologic mechanisms that may contribute to the different immune outcomes observed with plasma-derived and recombinant FVIII products.

Prevalence of malignancies among U.S. male patients with haemophilia: a review of the Haemophilia Surveillance System

The prevalence of malignancies in US male patients with haemophilia, with or without concomitant viral infections, remains unknown. To estimate the prevalence of malignancy in US male patients with haemophilia. We investigated the prevalence of malignancies among male patients with haemophilia using data from a six-state haemophilia surveillance project. Case patients with malignancies were identified using International Classification of Diseases, 9th Revision, Clinical Modification codes abstracted from hospital records and death certificates during the surveillance period. Cancer prevalence rates were calculated for each year during the surveillance and compared with age- and race-specific prevalence rates among the U.S. male population obtained from the Surveillance, Epidemiology and End Results (SEER) Program. A total of 7 cases of leukaemia, 23 cases of lymphoma and 56 classifiable solid malignancies were identified among 3510 case patients during a total of 15,330 annual data abstraction collections. The rates of leukaemia, lymphoma and liver cancer among case patients were significantly higher than the rates among U.S. males as judged by prevalence ratios of 3.1 [95% confidence interval (CI) = 1.4-7.0] and 2.9 (95% CI =1.8-4.6), respectively. In contrast, the prevalence ratio of prostate cancer was lower than expected at 0.49 (95% CI = 0.31-0.77). Overall the prevalence of most cancers among case patients was similar to that of the U.S. male population. However, patients with haemophilia who have unexplained symptoms should be evaluated for malignancy.

Recombinant and plasma-derived factor VIII products induce distinct splenic cytokine microenvironments in hemophilia A mice

The use of plasma-derived factor VIII (pdFVIII) concentrates in hemophilia A has been reported to result in reduced anti-FVIII antibody formation. In this study, we have investigated whether the cytokine microenvironment induced by pdFVIII has an influence on reducing anti-FVIII antibody titers in hemophilic mice. Microarray and confirmatory quantitative reverse transcription polymerase chain reaction (RT-PCR) experiments show that pdFVIII infusion causes a different transcriptional profile in dendritic cells than recombinant FVIII (rFVIII). Both treatments caused up-regulation of proinflammatory gene expression, but rFVIII and pdFVIII treatments promote expression of genes that induce Th1 and Th2 responses, respectively. Moreover, administration of rFVIII or pdFVIII concentrates resulted in distinct T-cell splenic cytokine microenvironments. rFVIII induced the release of Th1 cytokines and IL-10, whereas pdFVIII induced the release of Th2 cytokines and transforming growth factor-β. We have also observed high titers of anti–human von Willebrand factor (VWF) antibodies in the pdFVIII-treated mice and propose that this results from antigenic competition. We further investigated the role of this phenomenon using infusions of FVIII and increasing concentrations of recombinant human factor IX (FIX). These studies show an inverse relationship between increasing concentrations of FIX and the production of anti-FVIII antibodies. In summary, these studies report new mechanisms that contribute to reduced anti-FVIII antibody development in hemophilia A after pdFVIII infusions.

Garlic compounds selectively kill childhood pre-B acute lymphoblastic leukemia cells in vitro without reducing T-cell function: Potential therapeutic use in the treatment of ALL

Drugs used for remission induction therapy for childhood precursor-B acute lymphoblastic leukemia (ALL) are nonselective for malignant cells. Several garlic compounds have been shown to induce apoptosis of cancer cells and to alter lymphocyte function. To investigate the effect of garlic on the apoptosis of ALL cells and lymphocyte immune function, cells from newly diagnosed childhood ALL patients were cultured with several commonly used chemotherapeutic agents and several garlic compounds. Apoptosis, lymphocyte proliferation and T-cell cytokine production were determined using multiparameter flow cytometry. At concentrations of garlic compounds that did not result in significant increases in Annexin V and 7-AAD staining of normal lymphocytes, there was a significant increase in apoptosis of ALL cells with no alteration of T-cell proliferation as determined by CD25/CD69 upregulation or interferonγ, interleukin-2 or tumor necrosis factor-α intracellular cytokine production. In contrast, the presence of chemotherapeutic agents resulted in nonselective increases in both lymphocyte and ALL apoptosis and a decrease in T-cell proliferation and cytokine production. In conclusion, we show selective apoptosis of malignant cells by garlic compounds that do not alter T-cell immune function and indicate the potential therapeutic benefit of garlic compounds in the treatment of childhood ALL.

Assessment of in vitro cytokine response in hemophilia A patients with or without factor VIII inhibitory antibody

Factor VIII (FVIII) inhibitor antibodies are produced in a proportion of hemophilia A patients. Development of anti-FVIII inhibitor antibodies is a T cell-dependent response, mediated by FVIII specific CD4(+) T cells. This study was performed to investigate the contribution of T helper (Th) cell-mediated cytokine response in inhibitor production. Peripheral blood mononuclear cells (PBMCs) were obtained from hemophilia A patients with (n = 14) or without inhibitor (n = 14) and from normal individuals (n = 14). Following stimulation of PBMCs with rFVIII and phytohemagglutinin (PHA) mitogen, the secreted cytokines, interferon-gamma (IFN-gamma), interleukin-10 (IL-10), and transforming growth factor-beta1 (TGF-beta1), in culture supernatant and the proliferative response were assessed using sandwich ELISA and (3)H-thymidine incorporation, respectively. No significant proliferative response to FVIII was observed, whereas PHA induced a strong response in all groups. No cytokine secretion was observed in response to FVIII stimulation. Although PHA induced IL-10, TGF-beta1 and IFN-gamma secretion in all groups, the level of IFN-gamma was significantly lower in hemophilia A patients than in normal individuals (p < 0.0001). The levels of TGF-beta1 and IL-10 were similarly higher in patients compared with normal subjects, but the difference was not statistically significant. Lack of FVIII-induced proliferative response and cytokine production together with reduced secretion of PHA-induced IFN-gamma in both groups of patients suggest involvement of nonspecific immunosuppression possibly due to hepatitis C virus (HCV) infection observed in the majority of patients.

Immune tolerance induction with a high purity von Willebrand factor/VIII complex concentrate in haemophilia A patients with inhibitors at high risk of a poor response

Immune tolerance induction (ITI) is effective in approximately 70% of haemophilia patients with inhibitors. Poor prognostic factors are age >6 years, ITI started >1 year from inhibitor development, inhibitor peaks >200 BU, inhibitor titre >10 BU when ITI is started and previously failed ITI. The objective of this study was to identify the effectiveness in ITI of a high purity von Willebrand factor/factor VIII (VWF/FVIII) complex concentrate in inhibitor patients at high risk of failure. Patients with severe or moderate haemophilia A and high responding inhibitors who had at least one poor prognostic factor for ITI failure were prospectively followed-up. Success was defined by undetectable inhibitor, recovery and half life >66% of expected values. ITI dose regimens were chosen by each haemophilia centre. Seventeen haemophiliacs (16 severe, one moderate), aged 4-54 years (median 23) were followed-up for 6-71 months. Poor prognostic factors were delayed-onset ITI (n = 16), age >6 years (n = 16), previously failed ITI (n = 4), inhibitor peak >200 BU (n = 2) and inhibitor >10 BU when ITI was started (n = 4). Complete success was obtained in nine patients (53%) after 4-30 months of treatment (median 24), including two of four patients who had previously failed ITI. Seven patients achieved a partial success, with sustained low inhibitor titres (median 1.5 BU, range 1.1-2.8) but abnormal recovery and/or half-life, while the remaining patient withdrew ITI after 12 months when the inhibitor titer was still 70 BU. These findings suggest that high purity VWF/FVIII complex concentrates are effective in ITI, even in patients at high risk of failure.

Risk of inhibitors in haemophilia and the type of factor replacement

PURPOSE OF REVIEW

Inhibitors in haemophilia are a serious complication that may render usual replacement therapy ineffective. The risk is greatest in previously untreated children with severe haemophilia A. The role of replacement factor VIII in this group is an important issue.

RECENT FINDINGS

Until now, few clinical studies have correctly taken into account the variety of cofactors involved in inhibitor development: genetic (familial antecedents, ethnicity, F8 and immune response genotypes), and environmental cofactors (age at first infusion, prophylaxis and intensity of treatment). This is a prerequisite to correctly evaluating the putative role of the type of factor replacement. Prospective cohort studies are therefore urgently needed. Depending on the expected inhibitor risk in the reference group, the intensity of the relationship between risk factor and endpoint, the duration of patient follow up, and the design of the study (balanced or unbalanced groups), cohorts including 200-500 previously untreated children should be sufficient to demonstrate an increased intensity of risk of about 2 or more with one product compared with another.

SUMMARY

Aside from clinical studies, fundamental research is essential to test the multiple hypotheses that could explain a difference in inhibitor risk between the currently available factor VIII concentrates in order to develop less immunogenic factor VIII.

Mechanisms of action of immune tolerance induction against factor VIII in patients with congenital haemophilia A and factor VIII inhibitors

In its most severe form, haemophilia A is a life-threatening haemorrhagic bleeding disorder that is caused by mutations in the factor VIII (FVIII) gene. About 25% of patients who receive replacement therapy with intravenous FVIII products develop neutralising antibodies (FVIII inhibitors) that inhibit the function of substituted FVIII. Long-term application of high or low doses of FVIII has evolved as an effective strategy for eradicating antibodies and inducing long-lasting immune tolerance. Despite clinical experience with the therapy, little is known about the immunological mechanisms that cause the down modulation of FVIII-specific immune responses or the induction of long-lasting immune tolerance against FVIII. This review summarises current knowledge of the immunological mechanisms that might be involved in the induction of immune tolerance against FVIII in patients with haemophilia A who have FVIII inhibitors. In addition to data from patients with haemophilia A, data from patients who have had organ transplants or have immune-related disorders, such as autoimmune diseases, are considered as well as data from animal models.

Effect of factor VIII concentrate on leucocyte cytokine receptor expression in vitro: relevance to inhibitor formation and tolerance induction

Inhibitor formation in haemophilia patients receiving factor VIII (FVIII) concentrate is a serious problem requiring tolerance induction therapy. Inhibitor antibody formation is dependent on interactions between leucocyte cytokines with their corresponding receptors. To investigate this we studied the effect of FVIII on cytokine receptor expression using multiparameter flow cytometry and a whole blood stimulation assay. Upregulation of many cytokine receptors was inhibited by plasma-derived FVIII (pdFVIII) in a dose-dependent manner on T cells, B cells and monocytes although interleukin (IL)-4Ralpha and IL-7Ralpha were upregulated on T cells. The decrease in cytokine receptor upregulation on B cells in the presence of pdFVIII, may result in reduced antibody production. Inhibition of CD132 in the presence of pdFVIII may result in immune tolerance in some recipients of pdFVIII. The immunomodulatory effects of pdFVIII were dose and batch dependent, some being more inhibitory than others. The inhibitory effects of prednisolone with pdFVIII, on cytokine receptor upregulation, were additive. Cytokine receptor expression was not altered in the presence of human recombinant FVIII (rFVIII) concentrate. These findings may explain the reports of less frequent inhibitor antibody formation in some recipients of pdFVIII concentrates. The use of pdFVIII, particularly the more inhibitory batches, may be more suitable than rFVIII for tolerance induction protocols. A clinical study needs to be undertaken to determine the significance of these in vitro findings.

Influence of the type of factor VIII concentrate on the incidence of factor VIII inhibitors in previously untreated patients with severe hemophilia A

Inhibitor development is the major treatment complication in children with severe hemophilia A. It is not clear whether the risk of inhibitors is higher with recombinant factor VIII or with plasma-derived factor VIII. We used multivariate analysis to compare 2 cohorts of previously untreated patients (PUPs) with severe hemophilia A: 62 patients treated with the same brand of high-purity plasma-derived FVIII (pFVIII) containing von Willebrand factor (VWF) and 86 patients treated with full-length recombinant FVIII (rFVIII). In addition to the usual end points (all inhibitors, high inhibitors), we also examined a third end point (high inhibitors and/or immune tolerance induction). The risk of inhibitor development was higher in patients treated with rFVIII than in patients treated with pFVIII, regardless of other risk factors (F8 genotype; nonwhite origin; history of inhibitors in patients with a family history of hemophilia; age at first FVIII infusion). The adjusted relative risk (RRa) for inhibitor development with rFVIII versus pFVIII was 2.4 (all inhibitors), 2.6 (high inhibitors), and 3.2 (high inhibitors and/or immune tolerance induction), respectively, depending on the end point (above). The pathophysiology of this large effect must be understood in order to improve the characteristics of recombinant products and to reduce the incidence of inhibitors to FVIII.

Canadian multi-institutional survey of immune tolerance therapy (ITT) - experience with the use of recombinant factor VIII for ITT

Immune tolerance therapy (ITT) is currently the most effective approach to eradicate inhibitors in patients with haemophilia A. Limited evidence suggests that the use of plasma-derived factor VIII (pdFVIII) for ITT may be associated with a greater success rate than recombinant factor VIII (rFVIII). Analysis of ITT cases in Canada offered the opportunity to examine the success rate of using rFVIII for ITT, as rFVIII has been used almost exclusively for Canadian haemophilia A patients since 1994. The results of 32 patients from five haemophilia treatment centres were collated. Three patients continue on ITT. Of the 29 patients who completed ITT, 25 (86.2%) used rFVIII exclusively, and four used pdFVIII exclusively or pdFVIII followed by rFVIII. The initial FVIII dosing frequency was once per day in 72.4% of patients at an average dose of 98 U kg(-1) (range 50-200). Eight patients (25%) received one or more adjuvant therapies. The median duration of ITT was 1.1 years (mean 1.5 years, range 9 days to 6 years). The overall success rate of the 29 patients who completed ITT was 79.3% (23/29), which is comparable with the results of immune tolerance registries. Our results suggest that the success rate of ITT using rFVIII is not inferior to the results with pdFVIII.

Differential Rates of Apoptosis in Bronchoalveolar Lavage and Blood of Lung Transplant Patients

BACKGROUND

Lung transplant tolerance depends on effective control of T-cell proliferation and activation. Commonly used immunosuppressive agents promote peripheral blood-derived lymphocyte apoptosis and inhibit production of cytokines involved in lymphocyte proliferation and survival. However, there have been no studies of the effectiveness of immunosuppressive treatments on apoptosis of T cells derived from the airways of lung transplant recipients. Our main aim was to compare apoptosis of T cells derived from peripheral blood and bronchoalveolar lavage (BAL) from lung transplant recipients, with no evidence of chronic or acute cellular rejection, and healthy volunteers. Lung transplantation may also be associated with increased apoptosis of airway epithelial cells. To investigate this possibility, we also examined apoptosis of epithelial cells derived from bronchial brushing.

METHODS

BAL, blood, and bronchial brushings were obtained from lung transplant recipients (n = 9) and age-matched controls (n = 15). T cell and epithelial cell apoptosis, Fas, Bax, Bcl-2, and p53 were evaluated by flow cytometry.

RESULTS

Increased apoptosis of peripheral blood T cells and decreased Bcl-2 were observed in the transplant patients. In contrast, there was no significant change in apoptosis of airway T cells or apoptosis-related proteins. Increased apoptosis and increased p53 were observed in the airway epithelial cells from the transplant recipients, possibly as a result of ineffective control of infiltrating cytotoxic T cells.

CONCLUSIONS

Immunosuppressive agents may not be as effective in inducing apoptosis of airway-derived T cells as peripheral blood-derived T cells after lung transplantation. These findings may have implications on the outcome of the immune response in the airways after immunosuppressive therapy and may be particularly relevant to lung allograft rejection.

Poststorage Leuko-Depleted Plasma Inhibits T-Cell Proliferation and Th1 Response In Vitro: Characterization of TGFβ-1 as an Important Immunomodulatory Component in Stored Blood

BACKGROUND

Poststorage, leuko-depleted blood transfusions have been associated with increased postoperative infections and improved allograft survival compared with prestorage leukocyte-depleted blood transfusion. Although the mechanism of this phenomenon remains to be fully elucidated, it is clear that the immunomodulatory effect is mediated by leukocytes/platelets or their products.

METHOD

The aim of this study was to investigate the in vitro effects of pre- and poststorage leuko-depleted plasma (LDP) and buffy coat LDP on T-cell proliferation and cytokine synthesis using multiparameter flow cytometry.

RESULTS

In cell cultures exposed to prestorage LDP and buffy coat LDP there were no significant changes compared with fresh blood. In cell cultures exposed to poststorage LDP, T-cells showed reduced expression of CD69, CD25 (IL-2Ralpha), CD122 (IL-2Rbeta) and CD132 (IL-2Rtau) and production of TNF-alpha and IL-2 but there was no significant alteration for IFN-tau or IL-4. Changes in cytokine/cytokine receptor synthesis and T-cell proliferation were shown to be directly proportional to poststorage LDP concentration. Some of these changes were characteristic of TGFbeta-1. Addition of TGFbeta-1 neutralising antibody to poststorage LDP, negated the immunosuppressive effect on PHA-stimulated PBMC cultures.

CONCLUSIONS

The decrease in T-cell proliferation and Th1 cytokines TNF-alpha and IL-2, may be one basis of altered immunoregulation resulting in increased rates of certain types of infections and increased graft tolerance reported in patients receiving poststorage LD blood transfusions. TGFbeta-1 is a major immunomodulatory component of poststorage LD blood transfusions.

Increased peripheral blood T-cell apoptosis and decreased Bcl-2 in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is an inflammatory airway disease, usually associated with cigarette smoking. Stimulated peripheral blood T cells from patients with COPD have an increased propensity to undergo apoptosis. The mitochondrial apoptotic pathway is regulated by pro-apoptotic proteins (including p53 and Bax) as well as anti-apoptotic proteins (e.g. Bcl-2) and cytokines (IL-2, IL-4 and IL-7). We hypothesized that alterations in expression of these apoptosis-related proteins, cytokines and cytokine receptors may be important in determining the susceptibility of T cells to undergoing apoptosis in COPD. We further hypothesized that inhaled corticosteroids (GCS) contribute to the increased rates of T-cell apoptosis observed in COPD. The process of apoptosis (assessed by Annexin V and ssDNA staining), as well as Bcl-2, Bax, p53, IL-2, IL-4 and receptors IL-7R, IL-4R and IL-2Rgamma were investigated in PHA-stimulated peripheral blood-derived T cells, using flow cytometry. Fifteen patients with COPD receiving inhaled GCS (four of who received additional prednisolone), eight patients with COPD receiving symptom control medication, and 16 control subjects were studied. T cells (CD4(+) and CD8(+)) from GCS-treated COPD patients showed an increased propensity to undergo apoptosis, associated with significantly decreased Bcl-2 and IL-7 receptor expression. No significant differences were observed for the COPD patients who were receiving symptom control medication. These findings may suggest a negative peripheral effect of inhaled GCS on the immune system in COPD, although the clinical significance of these effects remains uncertain.

Bacillus cereus central line infection in an immunocompetent child with hemophilia

Bacillus species are increasingly recognized as pathogens in immunocompromised patients. The authors report a case of Bacillus cereus infection of a central line in an immunocompetent patient with hemophilia, which required line removal for complete cure.

Residual cell content in plasma produced by three centrifugal apheresis procedures

BACKGROUND

Understanding the impact of collection procedures on the residual amount of blood cells in plasma for transfusion and for fractionation is of current interest. This prospective work evaluated plasma donations collected on an apheresis machine (PCS 2, Haemonetics) with three different automatic centrifugal apheresis procedures, currently largely used in the US (Revision G) and in Europe (Revision F), and included a new procedure that uses a high-separation core (HSC) that is designed with a second separation chamber to further separate cells from plasma.

STUDY DESIGN AND METHODS

A total of 90 collection procedures have been performed from a population of 37 donors, under comprehensively standardized conditions. There were 30 well-matched donors in each group. Plasma aliquots were taken from the plasma units within 30 minutes of the end of the collection procedures and immediately assessed for WBCs, RBCs, PLTs, and supernatant Hb.

RESULTS

In Revision F and Revision G plasma donations, the mean numbers of WBCs were 83.1 x 10(4) and 311 x 10(4) per L; PLTs, 5.01 x 10(9) and 20 x 10(9) per L; and RBCs, 58 x 10(6) and 43 x 10(6) per L, respectively [corrected]. Significantly lower values were found with the HSC procedure (mean WBC, RBC, and PLT counts, 3.01 x 10(4)/L [p < 0.05], 9 x 10(6)/L [p < 0.001], and 3.5 x 10(9)/L [p < 0.001], respectively). The amount of free Hb was similar in all three procedures.

CONCLUSION

Significant differences in numbers of cells in plasma were found depending on the centrifugal procedures used and the design of the separation bowl. The lowest level of cell contamination was found with the new HSC bowl, which without a filtration step, yielded plasma that met the standard for WBC-reduced plasma. Plasma collectors can select the most appropriate method of plasma collection based on donor criteria, use of plasma (transfusion, viral inactivation, or fractionation), and local or international regulations, when in place.

Increased production of TGF-beta and apoptosis of T lymphocytes isolated from peripheral blood in COPD

Chronic obstructive pulmonary disease (COPD) is associated with inflammation of airway epithelium, including an increase in the number of intraepithelial T cells. Increased apoptosis of these T cells has been reported in the airways in COPD, and although this process is critical for clearing excess activated T cells, excessive rates of apoptosis may result in unbalanced cellular homeostasis, defective clearance of apoptotic material by monocytes/macrophages, secondary necrosis, and prolongation of the inflammatory response. Lymphocytes are known to traffic between the airway and the peripheral circulation, thus we hypothesized that in COPD, circulating T cells may show an increased propensity to undergo apoptosis. We analyzed phytohemagglutinin (PHA)-stimulated peripheral blood T cells from COPD patients and controls for apoptosis using flow cytometry and staining with annexin V and 7-aminoactinomycin D. As several pathways are involved in induction of apoptosis of T cells, including transforming growth factor (TGF)-beta/TGF receptor (TGFR), TNF-alpha/TNFR1, and Fas/Fas ligand, these mediators were also investigated in peripheral blood samples from these subject groups. Significantly increased apoptosis of PHA-stimulated T cells was observed in COPD (annexin positive 75.0 +/- 14.7% SD vs. control 50.2 +/- 21.8% SD, P = 0.006), along with upregulation of TNF-alpha/TNFR1, Fas, and TGFR. Monocyte production of TGF-beta was also increased. In conclusion we have demonstrated the novel finding of increased apoptosis of stimulated T cells in COPD and have also shown that the increased T-cell death may be associated with upregulation of apoptotic pathways, TGF-beta, TNF-alpha, and Fas in the peripheral blood in COPD.