Leucodepletion for transmissible spongiform encephalopathies

Transmissible spongiform encephalopathies (TSEs) have been recognised around the world for many years. Creutzfeldt-Jakob disease (CJD), one of the human forms of TSE, has been studied widely and thus far has not proved a great threat to human health. The emergence of two new TSEs--bovine spongiform encephalopathy (BSE) in cattle and variant Creutzfeldt-Jakob disease (vCJD) in humans in the UK--has caused great concern. BSE has had an economic impact and vCJD is a threat to human health. It has been shown that these two diseases are caused by the same prion agent and are linked. Research indicates that vCJD behaves differently to CJD and there is strong evidence to suggest that vCJD is present in lymphoid tissues and B lymphocytes, which presents a theoretical risk that it may be transmitted by transfusion of blood and blood products. To minimise/prevent this risk, the UK government has decided that plasma should be sourced from abroad and has instructed the National Blood Service to leucodeplete all blood and blood products, at a cost of 70 million pounds per annum, although it is not known if this will remove this risk.

Hepatitis C antibodies in asymptomatic first-time blood donors in The Gambia: prevalence and risk factors

This study evaluates the seroprevalence and risk factors for hepatitis C (HCV) antibodies in asymptomatic first-time blood donors in The Gambia. The study population includes 460 blood donors (age range: 18-40 years [mean: 27.5]) who attended the Royal Victoria Teaching Hospital from July to December 2002. Antibodies to hepatitis C are determined using and enzyme-linked immunosorbent assay (ELISA) test system. The prevalence of hepatitis C found in this study was 1.1% (95% CI, 0.16-1.12). Previous history of sexually transmitted disease, married men in polygamous relationships, and hospital or clinic-based workers were determined to be at risk of acquiring hepatitis C. The study shows that seroprevalence of hepatitis C in The Gambia is low compared to other countries in the region.

Studying the Impact of Presence of Alpha Acid Glycoprotein and Protein Glycoprotein in Chronic Myeloid Leukemia Patients Treated with Imatinib Mesylate in the State of Qatar

Despite the efficacy of imatinib mesylate (IM) in treating chronic myeloid leukemia (CML), there is a high degree of resistance. Alpha- 1-acid glycoprotein may reduce drug efficacy through its ability to interact with IM and blocks it from reaching its target, while protein glycoprotein (PGP) may reduce the intracellular concentration of the drug via an active pump mechanism. We thus investigated the correlation between AGP and PGP levels and the resistance/response to treatment. A total of 26 CML patients were investigated for AGP and PGP levels at diagnosis and during treatment. There was no significant difference or correlation between AGP levels and the different groups of patients. There was also no significant difference in the fluorescence intensities of PGP levels among the different patient groups. The resistance observed in our CML patient population could not be correlated with AGP and PGP levels. There was no significant pattern of AGP and PGP expression, irrespective of the response or resistance to treatment.

A mixed exercise training programme is feasible and safe and may improve quality of life and muscle strength in multiple myeloma survivors

Background

Exercise programmes are beneficial for cancer patients however evidence is limited in patients with multiple myeloma (MM), a cancer that is characterised by osteolytic bone disease, giving rise to high levels of bone morbidity including fractures and bone pain.

Methods

We conducted a single arm phase 2 study of an exercise programme (EP) as rehabilitation for treated MM patients, to evaluate feasibility, effects on QOL and physiological parameters. Patients were given individualised programmes, comprising stretching, aerobic and resistance exercises, carried out under supervision for 3 months then at home for a further 3 months.

Results

Study uptake was high, 60 of 75 (80%) patients approached consented to the study. Screen failures (11, due to fracture risk and disease relapse) and patient withdrawals (12) resulted in a final 37 patients enrolling on the programme. These 37 patients demonstrated high attendance rates in the supervised classes (87%), and high levels of adherence in home exercising (73%). Patients reported better QOL following the EP, with improvement in FACT-G and Fatigue scores over time from baseline (p<0.01 for both, one-way repeated measures ANOVA) to 6 months. Upper and lower limb strength also improved on the EP, from baseline to 6 months (p<0.01 for both). There were no adverse reactions.

Conclusions

An EP in MM patients is feasible and safe, with high attendance and adherence. Benefits in QOL, fatigue and muscle strength await confirmation in randomized studies, prompting urgent evaluation of the benefits of EP in the rehabilitation of MM patients.

Prevalence of HIV-1, HIV-2, hepatitis C and co-infection in The Gambia

BACKGROUND

In most West African countries, the distribution and risk factors for co-infection with Human Immunodeficiency Virus (HIV) and Hepatitis C Virus (HCV) is unknown despite the current HIV epidemic and evidence of increasing prevalence of HCV in the region.

OBJECTIVE

This study aimed to evaluate the distribution and the risk factors for the transmission of co-infection between HIV and HCV in The Gambia.

METHODS

A total of 1500 persons referred for HIV serology at the Royal Victoria teaching Hospital were interviewed following informed consent to obtain information on their demographic variables, knowledge of sexually transmitted diseases and their prevention, and patterns of risk behavior. Blood was collected and tested for anti-HIV and anti-HCV antibodies by Enzyme Linked Immunosorbent Assay (ELISA).

RESULTS

In the general population, the prevalence of HIV was 6.7%, while that of HCV was 2.1%. Both infections occurred more frequently in males than in females. HIV and HCV coinfection rate was 0.6%. Co-infection was significantly more common in males than females. All types of infection--HIV, HCV and HIV/HCV co-infections occurred much more in polygamous settings than in monogamy.

CONCLUSION

This study has demonstrated the extent of coinfection with HIV and HCV in The Gambia. The prevalence of female circumcision may be a contributory occurrence factor in the transmission of HIV but not in that of HCV.

CD4+ lymphocyte values and trends in individuals infected with human immunodeficiency virus and/or co-infected with hepatitis C virus in the Gambia

OBJECTIVES

This study was undertaken to monitor the CD4+ lymphocyte count in individuals infected with Human Immunodeficiency Virus (HIV) and/or co-infected with Hepatitis C Virus (HCV) and to compare this with the counts in normal individuals in The Gambia.

METHODS

Blood samples were taken from 1500 individuals referred for HIV serology at the Royal Victoria Teaching Hospital (RVTH) following informed consent. Samples were tested for antibodies to HIV by the Murex ELISA, antibodies to HCV by the Ortho ELISA, and CD4 counts determined by the Dynalimmunomagnetic cell isolation method

RESULTS

Of the 1500 patients screened for HIV and HCV antibodies, 6.7% (101/1500) were infected with HIV, 0.6 % (9/1500) were co-infected with HCV and 1.5 % (22/1500) were infected with HCV alone. Almost half (44.6%; 25/56) of HIV-1 infected patients had a CD4+ lymphocyte count at diagnosis of 200 cells/microl or less as compared to 41.7 % (10/24) of HIV-2 and 75% (6/8) of HIV-D infected patients. The rate of CD4 decline was higher among HIV/HCV co-infected persons than individuals infected with HIV or HCV. The rate of decline was higher among men than women. These differences did not reach statistical significance due in large part to the small number of participants who completed the programme. The CD4+ lymphocyte count of apparently healthy Gambian male and females was 489 cells/microl and 496 cells/microl respectively. This rate is lower than that reported for Caucasians, but in agreement with the global range.

CONCLUSION

A significant progressive decline in CD4+ lymphocyte count was observed among the female control group who were negative for HIV and HCV. This finding is unclear and calls for a longitudinal study involving a cohort of women in this region.

Preferential survival of acute lymphoblastic leukemia cells at 33°C is associated with up-regulation of bcl-2

An important feature of childhood acute lymphoblastic leukemia (ALL) is the risk of testicular relapse in affected males, which may occur months or years after induction of remission. However, little is known about the factors that regulate leukemic cell survival and resistance to chemotherapy in the testis. In the present study, incubating ALL cell lines and primary cells from ALL patients at 33 degrees C resulted in increased survival, resistance to chemotherapeutic agents and upregulation of bcl-2. Acute myeloid leukemia cell lines incubated at 33 degrees C also showed increased survival and resistance to chemotherapeutic agents, but did not demonstrate upregulation of bcl-2. This may be important in determining survival of ALL cells at lower temperatures in the testis.

Human immunodeficiency virus and hepatitis C co-infection in sub-Saharan West Africa

Co-infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) is becoming a major global problem, leading to increased morbidity and mortality in developed countries. Co-existence in sub-Saharan West Africa of a high prevalence of HIV and HCV, which share similar behavioural risk factors and modes of transmission, must be seen in the broader context of an emerging third epidemic of HIV and HCV co-infection, as many factors that may affect the spread of HIV and HCV co-infection are endemic in the continent, including host factors such as sexual behaviour, presence of other sexually transmitted diseases, female and male circumcision status, percutaneous and perinatal exposure, and poverty. This review examines the epidemiology, risk factors and transmission of HIV and HCV co-infection and draws attention to the possible emergence of an epidemic of HIV and HCV co-infection in the region.

Human breast milk immunology: a review

Breast feeding has been shown to enhance the development of the immune system of the newborn as well as provide protection against enteric and respiratory infections. It has been suggested that implementation of breast feeding programs has the potential to save hundreds of thousands of lives worldwide. Human milk is a bodily fluid which, apart from being an excellent nutritional source for the growing infant, also contains a variety of immune components such as antibodies, growth factors, cytokines, antimicrobial compounds, and specific immune cells. These help to support the immature immune system of the newborn baby, and protect it against infectious risks during the postnatal period while its own immune system matures. This article reviews some of the factors in human breast milk that give it these important properties.

Differential expression of CD180 and IgM by B-cell chronic lymphocytic leukaemia cells using mutated and unmutated immunoglobulin VH genes

We have studied the surface expression of the Toll-like receptor family member CD 180 on cells from 78 patients with B-chronic lymphocytic leukaemia (B-CLL). B-CLL cells had variable levels of CD 180 expression, but this was always less than that expressed by normal blood B cells and was stable for 24 months. Significantly higher levels of CD 180 were expressed by B-CLL cells with mutated IGVH genes compared with those using unmutated IGVH genes. This was in contrast to the higher levels of expression of surface immunoglobulin M by B-CLL cells using unmutated, rather than mutated IGVH genes. CD 180 was functional on B-CLL cells from some of the patients, as shown by the increased expression of CD 86 following incubation in vitro with anti-CD 180. The differential expression of CD 180 amongst B-CLL patients is one more marker that may define more precisely the different biological properties of this heterogeneous disease.

Is the liver an important site for the development of immune tolerance to tumours?

Despite the enormous interest in the field of tumour immunology, and the development of vaccine based strategies for immunotherapy of tumours, results in patients with cancer have been disappointing. This is partly due to the lack of development of clearly defined anti-tumour immune responses. The basis for the induction of specific anti-tumour non-responsiveness is not known. Recently, the liver has been recognised as an important organ in the regulation of peripheral immunological responses. It is characterised by a remarkable ability to induce tolerance to antigens from a variety of sources. Oral tolerance to food antigens, antigens from gut flora and other antigens administered via the oral route is partly dependent upon local immunoregulation in the liver. Transplantation of liver tissue shows a remarkable ability to induce tolerance in some species, not only to liver tissue but also to other organs and tissues transplanted at the same time. This tolerance can be transferred by adoptive transfer of lymphocytes. It has been suggested that the establishment of persistent infection in the liver by hepatitis viruses, may partly depend on the tolerogenic environment of the liver, and that this may also play a role in the development of hepatocellular carcinoma in patients with chronic infections with these viruses. The liver is also a common and an important site for the development of metastases from many primary tumours. This is partly dependent upon the anatomic location and structure of the liver, but may also partly reflect the exploitation of the tolerogenic environment in the liver, allowing micrometastases to colonise and grow. This may account for the fact that the liver is such a common site for metastasis. Furthermore, once tolerance to tumour antigens is established in the liver, tolerated lymphocytes may migrate from the liver back to primary tumours and exacerbate immunological non-responsiveness at tumour sites. Indeed, if this happens early in tumour development, liver dependent tolerance to tumour antigens may play a significant role in tumour progression, and may partly determine impaired tumour responses in vaccine based immunotherapy strategies.

Exercise for breast cancer survival: the effect on cancer risk and cancer-related fatigue (CRF)

To date, all epidemiological research in this area has focused on the relationship between physical activity level and the risk of breast cancer in healthy women, or more recently, those who have recovered from the disease. Most of this research highlights the fact that those women who are physically active are at a reduced risk of the disease. Although physical activity is similar to exercise, it lacks the specificity of a prescribed exercise training program. Consequently, such research can only be viewed as a promising indicator of the beneficial effect that regular exercise may have for breast cancer survivors. Furthermore, due to the nature of such research, there has been a failure to provide specific evidence concerning the most suitable modality, duration, intensity, and frequency of training for risk reduction in breast cancer survivors. Thus, evidence aiding the correct prescription of exercise for this population has been lacking. More promising evidence is provided by randomized controlled trials, which examine the effect of exercise on specific risk factors and provide convincing scientific rationale for the use of exercise among breast cancer survivors. These studies not only provide understanding of the physiological mechanisms by which exercise can be effective at aiding a reduction in breast cancer risk, but also allow conclusions on the correct prescription to be drawn. Additionally, exercise has proven to be effective in combating cancer-related fatigue (CRF), significantly improving both quality of life outcomes (QOL) and physiological capacity in women who have survived breast cancer. In order to promote a wider understanding of the beneficial effect that exercise holds for this population regarding reduction of breast cancer risk and CRF, this review discusses this research, making conclusions regarding the necessary training prescription to elicit such benefits.

Evaluation of the Taguchi methods for the simultaneous assessment of the effects of multiple variables in the tumour microenvironment

Background

The control of proliferation, differentiation and survival of normal and malignant cells in the tumour microenvironment is under the control of a wide range of different factors, including cell:cell interactions, cytokines, growth factors and hormonal influences. However, the ways in which these factors interact are poorly understood. In order to compare the effects of multiple variables, experimental design becomes complex and difficult to manage. We have therefore evaluated the use of a novel approach to multifactorial experimental design, the Taguchi methods, to approach this problem.

Method

The Taguchi methods are widely used by quality engineering scientists to compare the effects of multiple variables, together with their interactions, with a simple and manageable experimental design. In order to evaluate these methods, we have used a simple and robust system to compare a traditional experimental design with the Taguchi Methods. The effect of G-CSF, GM-CSF, IL3 and M-CSF on daunorubicin mediated cytotoxicity in K562 cells was measured using the MTT assay.

Results

Both methods demonstrated that the same combination of growth factors at the same concentrations minimised daunorubicin cytotoxicity in this assay.

Conclusions

These findings demonstrate that Taguchi methods may be a valuable tool for the investigation of the interactions of multiple variables in the tumour microenvironment.

Cytotoxic CD4+ T cells in patients with B cell chronic lymphocytic leukemia kill via a perforin-mediated pathway

BACKGROUND AND OBJECTIVES

B-cell chronic lymphocytic leukemia (B-CLL) is a clonal expansion of CD5+B cells that accumulate due to their uncontrolled growth and resistance to apoptosis. We have previously shown that up to 50% of blood CD4+ T cells in B-CLL patients have a cytotoxicity-related CD28- CD57+ phenotype and high content of both granzyme B and perforin (PF). In this study we investigate the cytotoxic potential of these cells against autologous B-CLL cells.

DESIGN AND METHODS

Blood CD4+ or CD8+ T cells were positively isolated from B-CLL patients and cultured under a range of conditions with autologous purified B-CLL cells and with bispecific [anti-CD3 x anti-CD19] antibodies. Apoptosis of labeled B-CLL cells was assessed using the change of mitochondrial membrane potential with the fluorescent dye DiOC6 and confirmed by annexin V binding.

RESULTS

There was time- and dose-dependent killing of B-CLL cells by both CD8+ and CD4+ T cells and this ranged from 6.6 - 68.0% for CD4+ cells and 6.4 - 57.8% for CD8+ cells. Almost complete inhibition by concanamycin A suggests that CD4+ T cells like CD8+ T cells induced apoptosis through a perforin-mediated pathway, but not via Fas/FasL (as indicated by lack of blocking with brefeldin A), tumor necrosis factor alpha or TRAIL.

INTERPRETATION AND CONCLUSIONS

This study shows that blood CD4+PF+ T cells enriched in B-CLL patients, are able to kill autologous B-CLL cells ex vivo, through bispecific antibodies via a perforin mediated mechanism.

Transendothelial migration confers a survival advantage to activated T lymphocytes: role of LFA-1/ICAM-1 interactions

The clearance of activated T lymphocytes by apoptosis is an essential component in the resolution of the immune response; however, certain signals received within inflamed tissue may result in the persistence of activated T cells. Our previous work has shown that, when compared with resting cells, effector cells migrate more efficiently across endothelium, thus such cells may be selectively recruited to sites of inflammation. We hypothesized that transmigration of T cells across endothelium might influence cell survival. We have generated T cell lines by culturing in IL-2 following PHA activation. These T cell lines die rapidly by apoptosis when deprived of IL-2 (53.7 +/- 4.0% survival after 24 h). In contrast, cells that have migrated across human umbilical vein endothelial cells (HUVEC) survived significantly better than control cells (80.3 +/- 3.6%, n= 18, P<0.001). Endothelial cell conditioned medium was also able to reduce apoptosis, but this effect was small when compared with the protective effect of transmigration. Culture of T lymphocytes on fibronectin, or RGD peptides, or in suspension with a range of chemokines active on T cells, including RANTES and lymphotactin had no effect on survival. In contrast, blocking LFA-l/ICAM-l interactions reduced the protective effect of transmigration (42.3 +/- 6.7% reduction). Culture of activated T cells on immobilized ICAM-l alone also increased survival. These results indicate that signals received by activated T cells during extravasation can influence their subsequent survival within tissue, and implicates the involvement of LF A-l/ICAM-l interactions.

Role of apoptosis in the pathogenesis of B-cell chronic lymphocytic leukaemia

B-cell chronic lymphocytic leukaemia (B-CLL) is a clinically heterogeneous disease characterised by the accumulation of a clonal population of B lymphocytes. This accumulation is considered to result from the prolonged survival of B-CLL cells arrested in the G0 stage of the cell cycle. However, when cultured in vitro, B-CLL cells die rapidly by apoptosis. It is now clear that a number of factors can delay or postpone the onset of apoptosis, including a number of cytokines and direct contact with different cell types. Although many drugs are now known to cause clinical improvement in B-CLL by causing apoptosis of B-CLL cells, in only a few cases have biological mechanisms been reported to have similar effects. It is now important to understand the role of these mechanisms in the pathogenesis and progression of B-CLL, and to devise strategies to exploit them for therapeutic use.

Expansion of CD4+ T cells with a cytotoxic phenotype in patients with B-chronic lymphocytic leukaemia (B-CLL)

Abnormal CD4/CD8 ratios and T-cell function have previously been shown in patients with B-chronic lymphocytic leukaemia (B-CLL). We have demonstrated that CD4+ T cells containing both serine esterase and perforin (PF) are increased in the blood of these patients. Using flow cytometry, we have shown that the CD4+ PF+ cells were CD57+ but lacked expression of CD28, suggesting a mature population. The same phenotype in CD8+ T cells is characteristic of mature cytotoxic T cells. However, in contrast to the CD8+ T cells, the CD4+ T cells were more frequently CD45RO positive than CD45RA positive, indicating prior antigen experience. In contrast, this population lacked expression of either CD69 or HLA-DR, arguing that they were not activated or that they are an abnormal population of T cells. Their constitutive cytokine levels showed them mainly to contain IL4 and not IFNgamma, suggesting a Th2 phenotype. The role of the CD4+ PF+ T-cell population is at present uncertain. However, this potentially cytotoxic T-cell population could contribute both to enhancing survival of the B-CLL tumour cells through production of IL4, and to the immunodeficient state frequently seen in patients with this tumour, independent of drug treatment.

CD5 B cells and B-cell malignancies

Over the past year, progress has been made in understanding of the physiology and disease associations of CD5+ (B1) B cells, although their exact role in pathogenesis remains unclear. Earlier studies on the negative function of CD5 within the B-cell receptor complex have been substantiated, and it seems likely that soon the signaling pathways used by this coreceptor will be elucidated. Progress in diagnosis, physiology, and etiopathogenesis of CD5+ malignancies has been made, particularly in B-cell chronic lymphocytic leukemia. The low-level expression of surface immunoglobulin has been explained by the mutations that occur in the associated CD79b. Two new potential tumor-suppressor genes have been identified in the hot spot of chromosome 13q, which provides an exciting step forward in understanding of the etiopathogenesis of some B-cell chronic lymphocytic leukemia. Activated signal transducers for activation of transcription factors molecules have been shown to be phosphorylated on different amino acids in B1 and chronic lymphocytic leukemia tumors, although the significance of this is, as yet, unclear. Finally, aberrant expression of CD40L by chronic lymphocytic leukemia T cells may contribute to the immunodeficiency that develops in these patients.

Regulation and function of adhesion molecules in B-cell chronic lymphocytic leukaemia

Cell surface expression of adhesion molecules in B-cell chronic lymphocytic leukemia (B-CLL) may determine the patterns of dissemination and infiltration. B-CLL cells express high levels of CD44, but expression of the leucocyte integrins was low or absent, while expression of VLA-4 is high. Most cases examined expressed no detectable ICAM-1, but some cases demonstrated levels of up to 30%. Levels of L-selectin were also variable, and expression could be induced/enhanced in vitro by incubation with cytokines such as IL-4, interferon-alpha and interferon-gamma. B-CLL cells bound normally to vascular endothelium, but binding to IL-1-activated endothelium was significantly lower than that of normal peripheral blood lymphocytes. Cytokine enhancement of L-selectin expression was not accomplished by changes in binding to vascular endothelium. Patterns of adhesion molecule expression and their regulation by cytokines may underly some of the clinical features of this disease.

Serum levels of TNF, IL-6 and sCD23 correlate with changes in lymphocyte count in patients with B-cell chronic lymphocytic leukaemia receiving interferon-alpha therapy

The control of cell growth and differentiation in B-cell malignancies may be regulated by the autocrine production of cytokines, several of which have been implicated in the growth and survival of B-cells. The effect of interferon-alpha (IFN) therapy in these disorders may be to disrupt autocrine growth or survival loops. We have measured levels of circulating IL-1b, IL-6, TNF-a and soluble CD23 (sCD23) in 8 patients with Binet stage A B-cell chronic lymphocytic leukaemia (B-CLL) receiving IFN therapy, and compared these with changes in the lymphocyte count following IFN therapy. Two patients developed anti-interferon antibodies while on IFN therapy, and in both them, the changes in lymphocyte count correlated significantly with the titre of anti-interferon antibodies, as well as serum levels of IL-6, TNF-a and sCD23. In one patient there was significant correlation with levels of IL-1b. One patient, who stopped and restarted IFN therapy, demonstrated correlation between lymphocyte count and levels of IL-6 and sCD23. In a further two patients, there was correlation with levels of sCD23 alone, while the remaining three patients showed no correlation between lymphocyte count and the serum cytokines measured. These results suggest that IFN therapy may alter levels of circulating cytokines in some CLL patients and that these effects may be associated with disease progression.

Cutaneous manifestation of leishmaniasis 40 years after exposure in a patient with chronic lymphocytic leukaemia

Most individuals infected with the protozoan parasite Leishmania do not demonstrate overt disease, because of effective immune protection produced by T-cell mediated immunity. Acquired defects in T-cell responses may lead to emergence of leishmaniasis many years after exposure in endemic areas. We describe a case of a 75 year old man, who presented with a cutaneous manifestation of leishmaniasis 40 years after exposure, co-incident with the diagnosis of chronic lymphocytic leukaemia.

Interferon-alpha, Bcl-2 expression and apoptosis in B-cell chronic lymphocytic leukemia

Interferon-alpha has been used as therapy in patients with B-cell chronic lymphocytic leukaemia (B-CLL), and is able to induce remissions in patients with early stage disease. Although interferon-alpha exhibits a wide variety of cellular effects, none of these have adequately explained the mechanism of action of interferon-alpha in B-CLL. Recent attention has focussed on the role of bcl-2 in B-CLL, and the regulation of bcl-2 expression by cytokines. B-CLL is characterized by the relentless accumulation in the peripheral blood and bone marrow of a monoclonal population of long-lived B-cells. However, when these cells are cultured in vitro, they die rapidly by apoptosis or programmed cell death. It has recently been demonstrated that B-CLL cells can be protected from apoptotic death in vitro by co-culture with cytokines, such as IL-1, IL-2, IL-4, IL-6 and interferon-gamma. The protection against apoptosis is correlated with increased levels of bcl-2 expression. It was suggested that interferon-alpha induced remissions in early stage B-CLL by interrupting these growth-factor dependent survival pathways and allowing the cells to die by apoptotic death in vivo. However, interferon-alpha has also been shown to protect B-CLL cells from apoptotic death in vitro. This suggests that interferon-alpha does not produce remission in B-CLL by direct effects on B-CLL cells in the circulation. Many of the cytokines which protect B-CLL cells from apoptotic cell death, are members of the cytokine receptor family which utilize a common family of signal transduction molecules. Further elucidation of these signal transduction pathways may offer the prospect of developing novel therapeutic strategies aimed at inducing apoptosis of the malignant clone in vivo.

Growth factors can protect B-chronic lymphocytic leukaemia cells against programmed cell death without stimulating proliferation

The proliferation and survival of B-chronic lymphocytic leukaemia (B-CLL) cells may be regulated by autocrine growth factor loops. Furthermore, it has been suggested the reduction in lymphocytosis following therapy with interferon-alpha may be associated with the interruption of autocrine growth factor production. We have therefore examined the effects of a number of cytokines on the proliferation of B-CLL cells, and also on the regulation of programmed cell death, and the role of interferon-alpha in these systems. In the ten patients studied, neither interferon-alpha alone or together with either interferon-gamma, IL1, IL4, IL6, TNF, or serum containing high levels of soluble CD23 was able to induce proliferation of B-CLL cells. Incubation with TPA or IL2 resulted in variable proliferative responses. Co-incubation with interferon-alpha enhanced TPA-induced proliferation in 4 cases, but reduced IL2-induced proliferation in all cases studied. In contrast, all the cytokines studied were able to protect B-CLL cells against programmed cell death, both spontaneous and that induced by hydrocortisone, with the exception of TNF. These data suggest a role for interferon-alpha in disrupting autocrine survival pathways rather than inhibiting proliferation.

Interferon-alpha up-regulates bcl-2 expression and protects B-CLL cells from apoptosis in vitro and in vivo

The bcl-2 oncoprotein, which is involved in the t(14,18) translocation, protects cells against apoptosis. We examined the effects of interferon-alpha (IFN-alpha) on bcl-2 protein expression and apoptosis in B-chronic lymphocytic leukaemia (B-CLL) cells. None of 12 patients with B-CLL examined expressed the t(14,18) translocation; however, all these, and seven other patients, expressed significant levels of bcl-2 protein. In vitro, IFN-alpha (500 U/ml over 18 h) increased bcl-2 expression on CLL cells (to 200 +/- 23% of control MCF, as determined by indirect immunofluorescence and flow cytometry, n = 10, P < 0.001). All of eight patients who received IFN-alpha (3 megaunits subcutaneously three times a week) demonstrated an increase in bcl-2 expression on circulating malignant cells. CLL cells undergo apoptotic cell death when cultured in vitro (35.6 +/- 10.3% DNA fragmentation after 18 h, n = 10). In the presence of IFN-alpha, however, DNA fragmentation was reduced to 6.6 +/- 5.8% (n = 10, P < 0.001). IFN-alpha also protected CLL cells against apoptosis induced by hydrocortisone and gamma irradiation (reducing DNA fragmentation from 63.9 +/- 12.6% to 10.8 +/- 4.5% and from 80 +/- 2.9% to 5.4 +/- 1.6%, respectively, P < 0.001 for both). The protective effect of IFN-alpha was dose dependent, and maintained for up to 24 h. Our data demonstrate that bcl-2 expression and apoptosis of CLL cells can be influenced by cytokines. In addition, it seems unlikely that the observed clinical responses to IFN-alpha in patients with CLL are due to a direct effect on the malignant cells.

Serum macrophage colony-stimulating factor (M-CSF) levels correlate with clinical response to interferon-alpha in patients with early-stage B-CLL

Interferon-alpha (IFN-alpha) reduces peripheral lymphocyte counts in B-CLL (CLL). In eight patients with stage 0 CLL on IFN-alpha therapy, peripheral lymphocyte counts fell to 61.7 +/- 19.5% of baseline at week 2 (P < 0.01), while serum M-CSF levels rose from 455 +/- 183 U/ml to 686 +/- 110 U/ml (P < 0.05). Neopterin levels also showed a significant rise. M-CSF levels were correlated with clinical response in these patients. Increased production of M-CSF and the activation of mononuclear phagocytes may be involved in clinical responses to IFN-alpha in early-stage CLL.

Resistance of chronic lymphocytic leukaemia cells to interferon-alpha generated lymphokine activated killer cells

Recent studies have shown that, when used in early stage disease, interferon-alpha (IFN-alpha) can produce a fall in the number of malignant cells in the peripheral blood of patients with B-CLL. In this study, we investigated the effect of IFN-alpha on natural killer (NK) cell and lymphokine-activated cell (LAK) activity in patients with B-CLL. In vitro, IFN-alpha (500 U/ml for 18 hours) induced LAK activity in patients with B-CLL (27.7 +/- 9.9%, n = 20), and IL-2 (500 U/ml for 5 days) produced similar activity (35.9 +/- 8.8%, n = 7). Despite the induction of LAK activity by IFN-alpha and IL2 in patients with B-CLL, the malignant cells remained resistant to both allogeneic and autologous LAK effectors. NK activity in patients with B-CLL is also low (23.1 +/- 7.2%, n = 20), and B-CLL cells were resistant to NK cell activity. In cold target competition assays, CLL cells did not compete with labelled K562 or Daudi targets in the NK and LAK assays, suggesting that the malignant cells are not recognised by the effector cells, and this may be related to low level of expression of the adhesion receptors, LFA-1 and ICAM-1. Finally, CLL cells were also resistant to antibody dependent cell mediated cytotoxicity, but were susceptible to antibody dependent complement mediated lysis. These results suggest that it is unlikely that the effects of IFN-alpha in B-CLL are due to the enhancement of NK or LAK activity.

Cytokine induction of leucocyte adhesion molecule-1 (LAM- 1) expression on chronic lymphocytic leukaemia cells

Leucocyte adhesion molecule 1 (LAM-1) participates in the binding of human leucocytes to high endothelial venules in peripheral lymph nodes. Other adhesion receptors which are involved include CD44 and the integrin family, CD11/CD18. In this study, B-cell chronic lymphocytic leukemia (B-CLL) cells were examined for the expression of these adhesion molecules, and for the way in which cytokines are able to modulate the levels of these receptors. B-CLL cells express significant but variable levels of LAM-1 and high levels of CD44. In contrast, these cells exhibit very low or absent amounts of surface CD11a, CD11b, or CD11c. Most CLL cells expressed no detectable levels of intercellular adhesion molecule-1 but some cases show levels of up to 30%. Following 24 h incubation with interferon alpha (500 U/ml), surface LAM-1 expression on peripheral blood E-negative cells from CLL patients rose to 330 +/- 127% of levels on control cells incubated with medium alone (n = 13, p less than 0.0005). Interleukin 4 (1 ng/ml) and interferon gamma (100 U/ml) also increased surface LAM-1 levels on these cells to 218 +/- 119% (n = 8, p less than 0.001) and 245 +/- 116% (n = 5, p less than 0.001) of control levels respectively. Induction of LAM-1 expression occurred over 48 h (greater than 50% of the increase was seen in the first 24 h) in a dose-dependent manner and required protein synthesis. The induction of LAM-1 expression on the malignant cells may, by altering the homing behaviour of these cells, relate to the reduction in peripheral leukaemic cells seen following treatment with interferon alpha in CLL.

Cellular cytotoxic function and potential in acute myelogenous leukaemia

Twenty-seven adult AML patients (13 with active disease and 14 in complete remission) were investigated for their cellular cytotoxic potential and function. All AML patients, whether with active disease or in complete remission, showed increased percentage of CD3+ lymphocytes expressing the cytotoxicity-linked cytoplasmic serine esterase, suggesting a higher than normal cytotoxic potential. However, when the cytotoxic function in these patients were analysed in terms of the natural killer and lectin-dependent cellular cytotoxicity, all AML patients, whether with active disease or in complete remission, had impaired target cell lytic activity. This paradox of cytotoxicity is most likely due to the immunosuppressive effect of the serum factor elaborated by leukaemia myeloblasts.

Recombinant alpha-interferons, thyroid irradiation and thyroid disease

Recombinant alpha-interferons are used as therapeutic agents in an increasing number of benign and malignant disorders. Long-term administration of recombinant alpha-interferon as a maintenance agent is associated with a small number of adverse side-effects which are responsible for patient intolerance of this drug. These include weight loss, alopecia and chronic fatigue, anorexia and depression syndrome. This latter syndrome needs to be distinguished from thyroid disease, which is documented in this report in a number of patients on recombinant alpha-interferon therapy.

Platelet derived malonyldialdehyde production in patients with thalassaemia major

Malonyldialdehyde, a product of membrane lipid peroxidation, was measured in the platelets of 16 normal subjects after stimulation with a variety of aggregating and stimulating agents. Nethylmaleimide and hydrogen peroxide generated the largest amounts of malonyldialdehyde. These agents were used to stimulate platelets from 11 patients with thalassaemia major suffering from iron overload due to repeated transfusion. Mean malonyldialdehyde concentrations were the same in normal subjects as in thalassaemic patients, but high concentrations were recorded in patients with severe iron overload. There was a highly significant correlation between malonyldialdehyde and serum ferritin concentrations in all thalassaemic patients. Platelet derived malonyldialdehyde may be a useful test of continuing membrane damage in patients with iron overload.