Transforming growth factor-beta1 suppresses interleukin-15-mediated interferon-gamma production in human T lymphocytes

One of the most remarkable means by which tumour cells manage to evade recognition and elimination by the immune system is the release of immunosuppressive mediators, such as interleukin (IL)-10 or transforming growth factor-beta (TGF-beta). For antitumour immunotherapies to reach their full potential, cytokine cocktails will have to be custom-tailored to the tumour's individual cytokine microenvironment. One of the components of such a cytokine cocktail may be interleukin (IL)-15, which has demonstrated an excellent stimulatory potential of antitumour immunity. In an in vitro model, we have previously been able to show that the negative effects of IL-10 on IL-15-mediated cytotoxic T-cell activation can be outweighed by the addition of interleukin (IL)-12. The mechanism by which TGF-beta may influence the effect of IL-15 remains poorly understood, however. We have therefore taken our T-cell model further and have studied the effect of TGF-beta on IL-15-mediated interferon-gamma (IFN-gamma) production. In activated, IL-15-stimulated peripheral blood T lymphocytes, TGF-beta suppressed IFN-gamma mRNA and protein levels by approximately 75%. This effect was likewise observed on both CD4+ and CD8+ T cells and, in contrast to the effect of IL-10 in this system, could not be neutralized by the addition of IL-12. Thus, immunotherapy for TGF-beta-producing tumours may benefit from the addition of TGF-neutralizing activity rather than IL-12.

Prevalence and outcome of intracranial haemorrhage in haemophiliacs--a survey of the paediatric group of the German Society of Thrombosis and Haemostasis (GTH)

A survey among centres of the paediatric group of the GTH was performed to evaluate the prevalence and outcome of haemophiliacs with intracerebral haemorrhage. A questionnaire sent to the centres covered the following points: number of patients with severe, moderate and mild haemophilia A and B; for each patient with ICH: birth date, age at bleeding, aetiology and neurological sequelae. Overall, 30 ICH in 744 haemophiliacs (4.0%) were reported by 17/40 centres (42.5%). There was no significant difference between the prevalence of patients with haemophilia A and B (3.5% vs. 6.3%) and among the age groups. Bleeding was diagnosed within 1 week of birth in 11/27 patients (41%). For 3 patients, no age-related information was given. The most important factor was trauma (17/30 = 57%), either during birth (9/30 = 30%) or later in life (8/30 = 27%). Seizures were common, occurring in 19/30 patients (63%). As 1 patient died after posttraumatic ICH, the neurological outcome of 29 patients could be evaluated. Psychomotor and statomotor retardation and cerebral palsy were reported in 17/29 (59%), 15/29 (51%) and 13/29 (45%) patients respectively. Only 7/29 (24%) showed no neurological sequelae. Severity of deficits was not correlated with birth date but to age at bleeding. Older children showed a better neurological outcome than neonates.

CONCLUSION

The frequency and outcome of ICH in haemophiliacs have not changed in our cohort over the past 20 years. Trauma at birth is an important risk factor for ICH in patients with haemophilia A or B. Intracranial haemorrhages in older children are rare, and a better outcome may be expected.

Induction of immune tolerance with recombinant factor VIII in haemophilia A patients with inhibitors

We report on 11 patients (nine unrelated and a brother pair) with severe haemophilia A and factor VIII (FVIII) inhibitor, in whom immune tolerance (IIT) was induced with recombinant FVIII (r-FVIII). Their age ranged from 11 months to 47 years. The number of exposure days (ED) at inhibitor detection varied from 11 to 130. Nine of the 11 patients were high responders ¿>10 Bethesda units (BU) with peak inhibitor levels ranging from 10 to 566 BU. The other two were low responders with peak levels between 0.7 and 2 BU. Before inhibitor detection, the patients had been receiving products of various purities. The IIT regimens were very heterogeneous, and the treatment schedule varied from a short period with 50 IU kg-1 every 2 days, followed by 100 IU kg-1 every 2 days and then 220 IU kg-1 daily. The outcome was considered successful when the inhibitor level fell to 0.6 BU or lower after IIT treatment. The outcome overall was successful in nine out of 11 patients (81.8%), with the nine successful cases comprising seven of the nine high responders (77.8%) and the two low responders. Definite failure of IIT was observed in one high responder after two different IIT regimens. A second high responder is still on IIT treatment. All patients in whom IIT was successful are currently receiving r-FVIII on demand or prophylactically at various dosages. Despite the variability of the patient characteristics and the IIT schedules, this study demonstrates that r-FVIII represents an effective alternative for the eradication of inhibitors through IIT.

Low rate of severe venous thromboses in children with ALL treatment according to COALL-92 and -97 protocol

Venous thromboses (VT) in children with ALL who were treated according to the COALL-89 protocol were reported to occur with a frequency of 2.1% (6/286). 4/6 of the reported VT were catheter related. However, in other cohorts of ALL patients treated according to American protocols the incidence of severe thromboses was 2-11%. Most of the VT were not catheter related, but were atypical thromboses like sinus venous thromboses. In these patients hereditary thrombophilia risk factors seemed to play a major role. In a 6 year period including the COALL protocols -92 and -97 only 10/684 (1.5%) children presented with symptomatic VT, and 7/10 thromboses were catheter related. Every thrombotic event could be successfully treated either by heparin administration or fibrinolytic agents. 2/10 VT were secondary due to a septic event. 5 out of 8 primary VT occurred after asparaginase/dexamethasone application during the reinduction therapy. In conclusion, symptomatic thrombotic events are very rare in the COALL studies. Important risk factors for development of VT appeared to be central lines, asparaginase application and infectious/septic complications. However, the role of genetic risk factors of thrombosis in these patients has still to be determined.

Detection of antiphospholipid antibodies in children and adolescents

The prevalence of antiphospholipid antibodies (APAs) has not yet been studied in children and adolescents with various diseases. We assayed plasma samples of 203 children and adolescents, aged 0.1 to 21 years (median 6 years), by enzyme-linked immunosorbent assay detecting immunoglobulin G (IgG) and IgM antibodies directed against cardiolipin, phosphatidylserine, and phosphatidic acid. According to their diagnosis children were divided into five groups: 10 patients with autoimmune and autoimmune-like diseases (group I); 88 patients with infections (group II); 20 patients with metabolic diseases (group III); 65 children with various other diseases (group IV); 20 healthy children without physical illnes (group V). Results were compared for statistical significance using Fisher's exact test. APAs were found in 65 of 203 patients. In all groups of patients the prevalence of APAs was increased compared with healthy children. The highest prevalence of APAs was found in patients with autoimmune or autoimmune-like diseases or infections. Thrombosis did not occur in children with increased APA levels. In 4 of 65 patients with detectable APAs bleeding was observed. However, three of these four children had additional coagulation abnormalities. We conclude that in children and adolescents increased APA titers may occur in a variety of diseases. The frequency of APA-related symptoms is low.

Management of severe chronic thrombocytopenia in von Willebrand's disease type 2B

Two patients with a long history of unexplained thrombocytopenia, eventually diagnosed with von Willebrand's disease (vWD) type 2B are reported. In one patient with platelet counts of 80 x 10(9)/l 1-desamino-8-D-arginine vasopressin (DDAVP) had a favourable effect during bleeding episodes. The second patient received intermediate purity von Willebrand's factor (vWF)/factor VIII concentrate (Haemate HS), which helped haemostasis during tooth extraction. It increased platelet counts from 15 to 30 x 10(9)/l, whereas platelet transfusions produced no increase, nor prevented severe bleeding during abdominal surgery. Thus the treatment of vWD type 2B might depend on the degree of thrombocytopenia. It is recommended that in patients with mild to moderately decreased platelet counts, DDAVP treatment can be tried, whereas in patients with severely decreased platelet counts intermediate purity vWF/factor VIII concentrate substitution is preferred. In addition, vWD type 2B should be considered in the differential diagnosis of any child with chronic thrombocytopenia as the treatment strategy is different.

The role of interleukin-10 (IL-10) in IL-15-mediated T-cell responses

Interleukin-15 (IL-15) is a potent T-cell stimulating factor, which has recently been used for pre-clinical in vivo immunotherapy. Here, the IL-15 effect on CD3-stimulated peripheral human T cells was investigated. IL-15 induced a significant T-cell proliferation and upregulated CD25 expression. IL-15 significantly enhanced T-cell production of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and IL-10. Between 10- and 100-fold greater concentrations of IL-15 were necessary to reach a biological effect equivalent to that of IL-2. Blockade of IL-2 binding to the high-affinity IL-2 receptor did not affect the IL-15 effects, suggesting that IL-15 did not act by inducing endogenous IL-2. Exogenously administered IL-10 significantly reduced the IL-15 and IL-2-mediated IFN-gamma and TNF-alpha production, whereas T-cell proliferation and CD25 expression were not affected. The inhibitory effects of exogenously administered IL-10 on T-cell cytokine production appeared indirect, and are likely secondary to decreased IL-12 production by accessory cells. Inhibition of endogenous IL-10 binding to the IL-10 receptor significantly increased IFN-gamma and TNF-alpha release from T cells. These data suggest that endogenous IL-10 can regulate activated T-cell production of IFN-gamma and TNF-alpha via a paracrine negative feedback loop. The observations of this study could be of relevance for the therapeutic use of IL-15 in vivo.

Humoral coagulation and early complications after allogeneic bone marrow transplantation

Alterations of the coagulation system that may lead to coagulation activation and thrombosis are common sequelae after allogeneic bone marrow transplantation (BMT). We performed prophylactic anticoagulation by low dose heparin (50 units/kg/day) and substitution of antithrombin (AT) concentrate to sustain plasma levels above 90% of pooled normal human plasma. Conventional tests for plasmatic hemostasis and substitution of AT concentrate were recorded for 50 patients until day +50 after BMT. Incidence of sepsis, graft-versus-host-disease [GVHD], capillary leakage syndrome [CLS] and veno-occlusive disease of the liver [VOD] were investigated and compared with the results of patients without any of these complications. Patients with proven sepsis (n = 6) showed decreased activity of AT, and a prolonged activated partial thromboplastin time (aPTT), while fibrinogen levels were slightly increased. This constellation was interpreted as mild to moderate activation of the humoral coagulation cascade. Patients with VOD (n = 10) showed an increased consumption of AT concentrate at day +7 followed by a decrease of prothrombin time, of clotting factors II and VII, and a prolongation of aPTT at days +11 to +18 after BMT. This suggests, that activation of coagulation precedes decreased synthesis of coagulation factors. Patients with CLS (n = 15) or GVHD > or = II degree (n = 14) showed no major alterations of coagulation parameters. In conclusion, after BMT, two types of coagulopathy were observed: (i) an activation of the coagulation cascade (i.e. sepsis and VOD) which was followed by (ii) a diminished synthesis of coagulation factors (VOD). In order to perform timely therapeutic interventions in the coagulation system in patients with sepsis and/or VOD it appears to be important to assess the clinical value of parameters for early detection of coagulation activation as thrombin-AT complexes, D-dimers and F1 + 2 fragments.

Humoral immunodeficiency in patients after bone marrow transplantation

Ex vivo IgG production was determined in 17 children and adolescents and in 14 adult patients between 10 months and 6 years after BMT. Twenty-four patients received allogeneic transplants. Seven patients were transplanted with autografts. Seven patients received immunosuppressive therapy. B cells were purified by positive selection with a CD20 antibody. After IL-2 or IL-10 stimulation, IgG production of SAC-preactivated B cells in patients with immunosuppression (median/range: 11/4-15 ng/ml or 14210-29 ng/ml) was significantly reduced compared with patients receiving allogenic (30/3-860 ng/ml or 33/2-3431 ng/ml; P < 0.01) or autologous transplants (75/7-1431 ng/ml or 269-/7-13600 ng/ml, P < 0.01). In 14/31 patients ex vivo IgG production was defective. Investigations of B cell function in patients with defective IgG production was performed significantly earlier after BMT compared with patients with normal IgG production ex vivo (2 +/- 1 years vs 3.3 +/- 1.5 years; P < 0.05). In addition, only patients with a B cell deficiency received immunosuppression. However, patients ex vivo IgG produced by B cells was decreased, but IgG production/sIgG+ B cells was within range of healthy volunteers. The number of IgG-committed B cells in these patients was significantly reduced compared to patients without deficiency (23/19-45/microliter vs 100/14-336/microliter; P < 0.05), indicating an in vivo switching defect. Although IL-10 is known to induce IgG-isotype switching in vitro, production of IL-10 by anti-CD3 activated MNCs obtained from patients with a switching defect did not differ from patients without B cell defects (1699/400-2662 pg/ml vs 724-112-1826 pg/ml). In nine patients IgG production and IgG production/sIgG+ B cells were impaired. The number of sIgG+ B cells was not decreased compared with patients without B cell deficiency (115/18-288/microliter), indicating a defective terminal differentiation of IgG-committed B cells to plasma cells. Although autocrine IL-6 is essential for plasma cell formation of isotype-determined B cells, it was comparable in patients with a terminal deficiency and without deficiency (3838/583-5967 pg/ml vs 2423/1643-6184 pg/ml). However, IL-10 production by anti-CD3 activated MNCs in patients with a terminal B cell defect (426/54-2262 pg/ml, P < 0.05) was significantly lower than in patients without deficiency, indicating a deviant cytokine production by T cells which might in part account for the B cell defect. Defective isotype switching as well as impaired terminal differentiation of B cells were found. Further analysis of factors regulating isotype-switching in vivo as well as cytokine receptor expression or signalling processes of differentiation factors in activated B cells might help to characterize the nature of these B cell deficiencies after BMT.

Interleukin 10 induced c-fos expression in human B cells by activation of divergent protein kinases

IL-10 is a potent mediator of human B cell growth and plasma cell formation. However, signal transduction of IL-10 in B cells is poorly understood. In this study the effect of IL-10 on the expression of the protooncogene c-fos was investigated, because Fos plays a potential role in the regulation of B cell proliferation and differentiation. B cells were purified from buffy coat preparations of healthy blood donors by positive selection using an anti CD20 monoclonal antibody and a MiniMACS separation unit. B cells were prestimulated with SAC for 48 hrs. Then, cells were incubated with medium or IL-10 (100 ng/ml) for 10 to 120 min. RNA was extracted by phenol/chloroform and c-fos expression was analyzed by PCR assisted mRNA assay. A significant 2-4 fold increase of c-fos expression was observed within 30 min of stimulation with IL-10 (p < 0.01). After 2 hrs c-fos expression declined to basal levels. The effect of IL-10 was dose-dependent with a maximum stimulation using 100 ng/ml of IL-10. The IL-10 effect on c-fos expression was not blocked by polymyxin B. Using the tyrosine kinase inhibitor genistein (10 microM) a complete inhibition of IL-10 induced c-fos expression was observed. In addition, H-7 (10 microM), a specific inhibitor of serine/threonine kinases, significantly blocked IL-10 mediated c-fos expression (p < 0.05). In conclusion, these data show that IL-10 induces c-fos expression in human B-cells by activation of tyrosine and serine/threonine kinases. Since this is the first report on IL-10 induced signal transduction, these data may help to identify the intracellular mechanisms by which IL-10 stimulates human B-cells.

Correlation of low histidine rich glycoprotein plasma levels with the occurrence of acute graft-versus-host disease after allogeneic bone marrow transplantation

Histidine-rich glycoprotein (HRGP) is a potent inhibitor of T cell activation and production of cytokines such as (gamma-IFN). gamma-IFN released by activated T cells is increased during a short-term period at the onset of GvHD after allogeneic bone marrow transplantation. Therefore we investigated HRGP plasma levels in patients after BMT. Blood was collected from 20 children before and up to 6 weeks after BMT. In patients without GvHD, HRGP plasma levels decreased during the first week after BMT to 237 +/- 60 micrograms/ml, compared with 302 +/- 104 micrograms/ml before transplantation. However, no significant changes in mean HRGP plasma levels were observed during the following 5 weeks of the posttransplantation period. Acute GvHD occurred in 10 of 20 patients between the second and third week after BMT. HRGP levels (mean +/- SEM) in patients with GvHD dropped during the first week to 158 +/- 32 micrograms/ml, compared with pretransplant levels of 240 +/- 48 micrograms/ml). In contrast to results in patients without GvHD, a second and significant decrease was obtained between the second and third week after BMT in patients with GvHD (161 +/- 35 micrograms/ml vs 84 +/- 13 micrograms/ml; p < 0.01). In the third week after BMT, HRGP levels were significantly lower in patients with GvHD as compared with patients without GvHD (166 +/- 29 micrograms/ml; p < 0.01). The decrease in HRGP in the second and third posttransplantation week was not a result of steroid treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-10 directly inhibits the interleukin-6 production in T-cells

IL-6 is a potent regulator of T-cell activation, proliferation and differentiation. Since IL-10 inhibits cytokine production by T cells, the effect of IL-10 on IL-6 production by T cells was investigated. IL-6 production by purified monocytes or T cells was detected from cell-free culture supernatants by ELISA after stimulation of the cells with LPS or an anti-CD3 monoclonal antibody for 3 days. Although the main source of IL-6 are LPS activated monocytes (29.6 +/- 10 ng/ml), T cells secreted sufficiently high levels of IL-6 (790 +/- 200 pg/ml) to stimulate the high affinity IL-6 receptor. IL-10 decreased anti-CD3 induced IL-6 mRNA expression by up to 80%. In addition, IL-10 significantly inhibited IL-6 release from T-cells. Highly purified, anti-CD3 activated T-cells secreted 600 +/- 150 pg/ml IL-6 compared to 21 +/- 2 pg/ml IL-6 following addition of IL-10 (10 ng/ml; P < 0.001). FACS analysis revealed a monocyte contamination of the T-cell preparations of less than 0.5%. In addition, no IL-1 production was detectable. Thus, in our experiments the effect of IL-10 on IL-6 production was independent of the presence of monocytes. Finally, inhibition of IL-6 production was not reversed by IL-2 (100 U/ml). In conclusion, IL-10 suppressed the synthesis of IL-6 by T-cells via a monocyte- and IL-2-independent mechanism. These results may help to understand the complex regulation of T-cell mediated cytokine production by IL-10.

Activation of protein kinase C induces de novo synthesis of the soluble interleukin-6 receptor in human B cells

The mechanism of protein kinase C (PKC) induced release of the soluble interleukin-6 receptor (sIL-6R) from human B cells was investigated. Phorbol myristat acetat (PMA)-induced activation of PKC significantly enhanced the release of sIL-6R from the human B-cell line SKW 6.4. The PMA effect was completely blocked by cycloheximide, whereas different inhibitors of proteases had no effect. In contrast to the effect on sIL-6R release, FACS analysis did not reveal any effect of PMA on the expression of IL-6R on the surface of SKW 6.4 cells. After 6 h of stimulation with PMA, analysis of mRNA expression using a polymerase chain reaction-(PCR)-assisted mRNA amplification assay, showed increased expression of a spliced mRNA encoding for a soluble form of IL-6R. Comparable to the results in SKW 6.4 cells, activation of purified human B cells with PMA induced a significant augmentation of sIL-6R release which was also sensitive to cycloheximide. In conclusion, a novel mechanism of sIL-6R release is reported involving de novo synthesis. Thus, sIL-6R release from human B cells is completely different compared with that described in hepatocytes, which involved rapid, proteolytic cleavage of the membrane-bound receptor but not de novo synthesis. The results of this study may help to understand the molecular control of sIL-6R release from human B cells.

Myeloablative radiochemotherapy and hematopoietic stem-cell rescue in poor-prognosis Ewing's sarcoma

PURPOSE

The prognosis of patients with multifocal primary and early or multiple relapsed Ewing's sarcoma is poor with conventional chemoradiotherapy and surgery. We evaluated the efficacy and feasibility of a myeloablative regimen administered as consolidation treatment for these patients.

PATIENTS AND METHODS

The ablative regimens consisted of simultaneous radiochemotherapy: 12 Gy hyperfractionated total-body irradiation (TBI; two doses of 1.5 Gy for 4 days) plus fractionated high-dose melphalan (30 to 45 mg/m2 for 4 days) followed by high-dose etoposide (40 to 60 mg/kg) with or without carboplatin (900 to 1,500 mg/m2) (hyper-ME +/- C). These regimens were applied in a dose-escalation study that included 17 patients. All patients underwent remission induction chemotherapy and local treatment before myeloablative therapy. Seven patients had multifocal primary Ewing's sarcoma, and 10 had early or multiple relapse. We performed a matched-cohort analysis of the 17 grafted patients with 41 historic controls matched for sex, age, diagnosis, extent of disease, interval from diagnosis to transplant in the transplant group, and interval from diagnosis to relapse in the control group.

RESULTS

The probability of relapse in the study patients is 52% at 6 years after the last event before transplantation. In the control group, the probability of relapse at 6 years was 98%. Eight of 17 treated patients are alive in complete remission at a median observation time of 49 months (range, 19 to 76) from the last event before transplantation. Probability of relapse-free survival in the study patients is 45% +/- 12% at 6 years after the last event before transplant, compared with 2% +/- 2% for the historic control group.

CONCLUSION

Myeloblative therapy with hyper-ME +/- C radiochemotherapy can improve the prognosis of multifocal primary and early or multiple relapsing Ewing's sarcoma.