COVID-19 as a mediator of interferon deficiency and hyperinflammation: Rationale for the use of JAK1/2 inhibitors in combination with interferon

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) elicits an interferon (IFN) deficiency state, which aggravates the type I interferon deficiency and slow IFN responses, which associate with e.g. aging and obesity. Additionally, SARS-CoV-2 may also elicit a cytokine storm, which accounts for disease progression and ultimately the urgent need of ventilator support. Based upon several reports, it has been argued that early treatment with IFN-alpha2 or IFN-beta, preferentially in the early disease stage, may prohibit disease progression. Similarly, preliminary studies have shown that JAK1/2 inhibitor treatment with ruxolitinib or baricitinib may decrease mortality by dampening the deadly cytokine storm, which - in addition to the virus itself - also contributes to multi-organ thrombosis and multi-organ failure. Herein, we describe the rationale for treatment with IFNs (alpha2 or beta) and ruxolitinib emphasizing the urgent need to explore these agents in the treatment of SARS-CoV-2 - both as monotherapies and in combination. In this context, we take advantage of several safety and efficacy studies in patients with the chronic myeloproliferative blood cancers (essential thrombocythemia, polycythemia vera and myelofibrosis) (MPNs), in whom IFN-alpha2 and ruxolitinib have been used successfully for the last 10 (ruxolitinib) to 30 years (IFN) as monotherapies and most recently in combination as well. In the context of these agents being highly immunomodulating (IFN boosting immune cells and JAK1/2 inhibitors being highly immunosuppressive and anti-inflammatory), we also discuss if statins and hydroxyurea, both agents possessing anti-inflammatory, antithrombotic and antiviral potentials, might be inexpensive agents to be repurposed in the treatment of SARS-CoV-2.

Distinguishing myelofibrosis from polycythemia vera and essential thrombocythemia: The utility of enumerating circulating stem cells with aberrant hMICL expression by flow cytometry

INTRODUCTION

Diagnosing BCR-ABL negative myeloproliferative neoplasms (MPN) may be challenging due to overlapping features and lack of robust discriminatory parameters, especially between essential thrombocythemia (ET) and prefibrotic myelofibrosis (MF). Circulating immature hematopoietic cells are variably present in polycythemia vera (PV), ET, and MF. The C-type lectin hMICL is aberrantly expressed on hematopoietic stem cells in the majority of acute myeloid leukemia patients. However, the hMICL expression in MPN, having varying propensity of leukemic transformation, is unsettled. We hypothesized that enumeration of immature cells by flow cytometry (FCM) could be a discriminatory tool in MPN diagnostics.

METHODS

By FCM, we quantified circulating stem cells with aberrant hMICL expression in 39 MPN patients, 10 age-matched controls, and in leukapheresis products from 10 patients with lymphoproliferative neoplasms. The utility of the FCM assay for discriminating MPN entities was evaluated by applying ROC curve analysis.

RESULTS

While hMICL was absent in control samples, MF patients had significantly more hMICL+ stem cells (median 15.2%) than PV and ET (0.0%, P = .001 and 0.0%, P = .002, respectively). By ROC curve analysis, the presence of hMICL+ stem cells (>0 cells) in peripheral blood reliably discriminates MF from ET and PV with a sensitivity of 80% and a specificity of 97%.

CONCLUSION

Enumeration of circulating hMICL+ stem cells by FCM can discriminate between MPN phenotypes and holds potential for monitoring disease evolution.

The calreticulin (CALR) exon 9 mutations are promising targets for cancer immune therapy

The calreticulin (CALR) exon 9 mutations are found in ∼30% of patients with essential thrombocythemia and primary myelofibrosis. Recently, we reported spontaneous immune responses against the CALR mutations. Here, we describe that CALR-mutant (CALRmut)-specific T cells are able to specifically recognize CALRmut cells. First, we established a T-cell culture specific for a CALRmut epitope. These specific T cells were able to recognize several epitopes in the CALRmut C terminus. Next, we established a CALRmut-specific CD4⁺ T-cell clone by limiting dilution. These CD4⁺ T cells recognized autologous CALRmut monocytes and hematopoietic stem cells, and T-cell recognition of target cells was dependent on the presence of CALR. Furthermore, we showed that the CALRmut response was human leukocyte antigen (HLA)-DR restricted. Finally, we demonstrated that the CALRmut-specific CD4⁺ T cells, despite their phenotype, were cytotoxic to autologous CALRmut cells, and that the cytotoxicity was mediated by degranulation of the T cells. In conclusion, the CALR exon 9 mutations are targets for specific T cells and thus are promising targets for cancer immune therapy such as peptide vaccination in patients harboring CALR exon 9 mutations.

Myeloproliferative neoplasms and inflammation: whether to target the malignant clone or the inflammatory process or both

The Philadelphia-negative myeloproliferative neoplasms (MPNs) are clonal disorders involving hematopoietic stem and progenitor cells and are associated with myeloproliferation, splenomegaly and constitutional symptoms. Similar signs and symptoms can also be found in patients with chronic inflammatory diseases, and inflammatory processes have been found to play an important role in the pathogenesis and progression of MPNs. Signal transduction pathways involving JAK1, JAK2, STAT3 and STAT5 are causally involved in driving both the malignant cells and the inflammatory process. Moreover, anti-inflammatory and immune-modulating drugs have been used successfully in the treatment of MPNs. However, to date, many unresoved issues remain. These include the role of somatic mutations that are present in addition to JAK2V617F, CALR and MPL W515 mutations, the interdependency of malignant and nonmalignant cells and the means to eradicate MPN-initiating and -maintaining cells. It is imperative for successful therapeutic approaches to define whether the malignant clone or the inflammatory cells or both should be targeted. The present review will cover three aspects of the role of inflammation in MPNs: inflammatory states as important differential diagnoses in cases of suspected MPN (that is, in the absence of a clonal marker), the role of inflammation in MPN pathogenesis and progression and the use of anti-inflammatory drugs for MPNs. The findings emphasize the need to separate the inflammatory processes from the malignancy in order to improve our understanding of the pathogenesis, diagnosis and treatment of patients with Philadelphia-negative MPNs.

Combination therapy with interferon and JAK1-2 inhibitor is feasible: Proof of concept with rapid reduction in JAK2V617F-allele burden in polycythemia vera

We report a 55 year old woman with post-ET PV for 12 years, who experienced resolution of severe constitutional symptoms within 3 days, a marked reduction in splenomegaly and a rapid decline in the JAK2V617F allele burden during combination therapy with interferon-alpha2a and ruxolitinib. Within 4 weeks the patient achieved complete hematological remission with normalization of peripheral blood counts and within 10 months the JAK2V617F-allele burden was reduced from 90% to 28%. Such a rapid decline in the JAK2V617F allele burden is highly unusual in PV-patients during low-dose IFN-alpha2 monotherapy and this finding warrants a prospective study with combination therapy.

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Combination therapy with low-dose Interferon (IFN) and ruxolitinib (rux) is feasible.

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IFN and rux promptly alleviates symptoms and rapidly induces complete hematological remission.

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IFN and rux reduces allelic burden more effectively than seen in conventional IFN or rux regimens.

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The combinatorial approach was successful in a patient with prior side-effects to IFN.

Inheritance of the chronic myeloproliferative neoplasms. A systematic review

This systematic review investigated the inheritance of the classical chronic myeloproliferative neoplasms (MPNs) including polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF) and chronic myelogenous leukemia (CML). Sixty-one articles were included and provided 135 families with a total of 341 participants distributed to various subtypes of MPN: 50% PV, 23% ET, 14% PMF, 10% CML and 3% non-MPN hematological disorder. Women developed the disease earlier than men (43.1 years vs 47.3 years; p = 0.074), while the general average age of onset was 46 years, notably younger than sporadic cases. The clinical phenotype of the families showed a homogenous (67%) and a heterogeneous (33%) pattern, with the majority being PV-PV pairs (36%) and PV-PMF pairs (17%), respectively. This observation suggests that the susceptibility gene (or genes) is not restricted to one subtype supporting the hypothesis of a mutation in an early multipotent stem cell. Furthermore, a major subgroup of families provided evidence of an autosomal dominant (AD) inheritance with reduced penetrance. This study suggests that the origin of MPNs may occur in at least three different settings: (i) a sporadic, (ii) genetic heterogeneity with polygenetic and environmental impact and (iii) a familial phenotype following an AD inheritance.

Systemic adverse events following rituximab therapy in patients with Graves' disease

BACKGROUND AND AIM

Rituximab (RTX) therapy has shown promising results in Graves' disease (GD), with or without ophthalmopathy. We examined the occurrence of adverse events in GD patients treated with RTX.

SUBJECTS AND METHODS

Ten patients received RTX and methimazole, while 10 patients received methimazole only. Adverse events were recorded, and the presence of circulating immune complexes (CIC) was measured as IgG, IgM and complement component 3 (C3) depositing on normal monocytes following incubation with patient plasma.

RESULTS

Five patients had benign infusion-related adverse events at first infusion. Two patients developed a serum sickness-like reaction 11 days after the first RTX-infusion. One of these patients developed diarrhea, raised orosomucoid levels, lowgrade inflammation in colonoscopic biopsies, and iridocyclitis 1 yr later. At day 14, the most pronounced immunoglobulin/ C3-adherent to the test monocytes, indicative of CIC, was observed in the presence of plasma from these 2 patients (p=0.003 to p=0.01 vs asymptomatic patients). A 3rd patient had recurrent fever and symmetric polyarthritis from day 38, and colonoscopy-verified ulcerative colitis at day 68. This patient had the 3rd highest increase in Ig deposition on monocytes by day 14. The arthralgias persisted in 2 of the patients, despite glucocorticoid rescue therapy.

CONCLUSIONS

We report articular adverse events in 3 and gastrointestinal symptoms in 2 out of 10 GD patients who received RTX without concurrent immunosupression. The joint symptoms were related to CIC formation.

Serum prolactin and thyrotropin responses to thyrotropin-releasing hormone in men with alcoholic cirrhosis

The serum concentrations of prolactin (PRL) and thyrotropin (TSH) in 12 males with alcoholic cirrhosis during basal condition and after stimulation with thyrotropin-releasing hormone (TRH) were compared with the concentrations in ten thiazide-treated hypertensive and nine normal men. The basal as well as the TRH-stimulated increase in serum PRL was significantly elevated in the cirrhotic males, while the increase in serum TSH was unchanged, compared with hypertensive and normal men. No correlation between clinical or laboratory parameters and serum PRL was found. Serum estradiol was equal in cirrhotic and control subjects and no correlation was found between serum PRL and serum estradiol. These findings favour the concept that raised serum PRL in cirrhotic patients might be caused by a diminished dopaminergic neurotransmission.

Sustained major molecular response on interferon alpha-2b in two patients with polycythemia vera

Quantitative assessment of the JAK2 V617F allele burden during disease evolution and ongoing myelosuppressive treatment is likely to be implemented in the future clinical setting. Interferon alpha has demonstrated efficacy in treatment of both chronic myeloid leukemia and the Philadelphia chromosome negative chronic myeloproliferative disorders. Reductions in the JAK2 V617F allele burden in patients treated with pegylated interferon alpha-2a (Peg-IFN-2a) have been demonstrated, although follow-up was relatively short. We report here the first profound and sustained molecular responses with a JAK2 V617F allele burden below 1.0% in two patients with polycythemia vera treated with interferon alpha-2b (IFN-2b). Discontinuation of IFN-2b in one of the patients was followed by a sustained long-lasting (12 months of follow-up) major molecular response.

Anagrelide treatment in 52 patients with chronic myeloproliferative diseases

In this retrospective multi-centre study, we report our experience with anagrelide in the treatment of thrombocytosis in patients with chronic myeloproliferative diseases. Our study included 52 patients (age 20-78 years). The initial anagrelide dose was, in general, 0.5 mg once daily and mean maintenance dosage was 1.7 mg/day. The overall response rate was 79% including 75% complete remission and 4% partial remission. Forty-two patients (81%) had adverse effects and in 29% of the study population, the adverse effects necessitated cessation of anagrelide. The most common adverse effect was moderate anaemia (50%). Two patients experienced erectile dysfunction which has been described only once previously in association with anagrelide treatment. One patient progressed to acute leukaemia. However, this patient had been pre-treated with two potentially leukaemogenic drugs and had only been in short-term treatment with anagrelide. Furthermore, a total of 13 events were recorded. More than 25% of these events occurred in patients with platelet counts between 400 and 600 x 10(9)/l and almost 40% of all events occurred in patients with platelet counts above 400 x 10(9)/l. This observation supports the hypothesis that aggressive control of thrombocytosis to a platelet count <400 x 10(9)/l might reduce the number of thrombohaemorrhagic events. Anagrelide is safe and effective in reducing the platelet counts, but a high proportion of the patients discontinue treatment because of the adverse effects of the drug.

SU6668 in idiopathic myelofibrosis--a rational therapeutic approach targeting several tyrosine kinases of importance for the myeloproliferation and the development of bone marrow fibrosis and angiogenesis

Idiopathic myelofibrosis is a chronic myeloproliferative disorder being featured by progressive accumulation of connective tissue in concert with marked neovascularization (angiogenesis) of the bone marrow. Both fibrogenesis and angiogenesis are considered to develop consequent to the intramedullary release of various growth-promoting factors from rapidly proliferating and dysplastic megakaryocytes. Among these growth factors are platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), transforming growth factor beta (TGF-beta) and vascular endothelial growth factor (VEGF). The protein kinase inhibitor SU6668 is a potent antiangiogenic inhibitor of receptor tyrosine kinases, including those of VEGFR, PDGFR, bFGFR, and c-kit. The hypothesis is that SU6668 may be an effective agent in the treatment of idiopathic myelofibrosis. This compound has an inhibitory target profile on several tyrosine kinases involved in the myeloproliferation, the development of myeloid metaplasia (bFGFR, PDGFR, VEGFR, and c-kit) and the development of the major stromal changes in the bone marrow - fibrosis and angiogenesis (bFGFR, PDGFR, and VEGFR).

Increased circulating platelet-leukocyte aggregates in myeloproliferative disorders is correlated to previous thrombosis, platelet activation and platelet count

Platelet-leukocyte adhesion may occur as a consequence of platelet activation and possibly plays a key role in the deposition of activated platelets and fibrin in the thrombotic plug. The aim of the present study was to assess by whole blood flow cytometry the presence of circulating platelet-leukocyte aggregates (PLA) and the platelet-leukocyte response to platelet agonist stimulation (ADP and TRAP) in 50 patients with chronic myeloproliferative disorders (MPD) and 30 controls. PLA were identified as platelet-granulocyte/monocyte aggregates (PGMA), platelet-monocyte aggregates (PMA) and defined as the percentage of leukocytes coexpressing the platelet-specific marker glycoprotein Ib. Compared to controls the mean percentage of PGMA and PMA was increased in unstimulated whole blood from patients with MPD (7.98 vs. 1.76%; p<0.001 and 12.34 vs. 3.2%; p<0.001, respectively). The percentage of PGMA was correlated to the platelet count (r=0.46; p<0.001), percentage of P-selectin (r=0.69; p<0.001) and thrombospondin (r=0.58; p<0.001) positive platelets and platelet expression of GPIV (r=0.33; p=0.02). The mean percentage of PGMA and PMA was significantly increased in ADP-stimulated whole blood of patients (57.14 vs. 47.92%; p=0.009 and 54.91 vs. 45.89%; p<0.001, respectively). Compared to patients without a history of thrombosis, patients having experienced microvascular disturbances or a thrombotic event had a higher mean percentage of PGMA and PMA in non-stimulated whole blood (10.07 vs. 6.34%; p=0.025 and 14.81 vs. 10.48%; p=0.021, respectively) and a higher percentage of PGMA in ADP stimulated whole blood (64.32 vs. 51.50%; p<0.01). These data document an increased frequency of PLA in non-stimulated whole blood in MPD associated with a previous history of thrombosis or microvascular disturbances.

Sustained remission of platelet counts following monoclonal anti-CD20 antibody therapy in two cases of idiopathic autoimmune thrombocytopenia and neutropenia

Idiopathic autoimmune thrombocytopenia and neutropenia (ITN) is a primary haemocytopenic disorder clinically characterised by recurrent mucocutaneous bleeding episodes and infections. Unlike in simple idiopathic thrombocytopenic purpura, the platelet deficiency of ITN tends to be chronic and difficult to treat. We describe two patients with ITN who obtained sustained remission of their platelet counts after therapy with the chimeric monoclonal anti-CD20 antibody Rituximab. In one of two cases, Rituximab also induced prolonged normalisation of the neutrophil count and disappearance of auto-antibodies. Our observations indicate that disturbed B-cell function plays a central role in the pathogenesis of ITN. Anti-CD20 antibody therapy seems to constitute a safe and efficient alternative to corticosteroids for the management of ITN patients with chronic thrombocytopenia.

[Clinical use of recombinant human thrombopoietin. Status and perspectives]

Thrombopoietin (TPO) is primarily produced by hepatocytes and regulates the production and differentiation of megakaryocytes and platelets in the bone marrow. The endogenous TPO level is increased when the megakaryocyte count is low, and high in aplastic anaemia and after myeloablative chemotherapy. TPO is cloned and manufactured by a recombinant technique for clinical use. Treatment with recombinant human TPO (rhTPO) after intensive chemotherapy may reduce the need for platelet transfusions. Administration of granulocyte colony-stimulating factor in combination with rhTPO has enhanced the mobilisation and harvest product of haematopoietic stem cells. Whether rhTPO is effective in the treatment of the myelodysplastic syndrome, aplastic anaemia, and other conditions with bone marrow insufficiency (including AIDS) is not yet known. In liver cirrhosis, the endogenous TPO level rapidly increases after liver transplantation. Accordingly, substitution of rhTPO may be indicated in advanced liver failure complicated by thrombocytopenia and bleeding.

[The chronic Philadelphia chromosome-negative myeloproliferative syndrome II. Clinical findings, diagnostics and treatment]

Polycythaemia vera (PV) and essential thrombocytosis (ET) are clinically characterised by non-specific neurologic symptoms, peripheral circulatory disturbances (acrocyanosis, wounds, erythromelalgia) or abdominal symptoms. The treatment of PV includes phlebotomy, antiaggregation and cytoreduction. In ET, the primary treatment is also low-dose aspirin except for patients presenting with a haemorrhagic diathesis. Hydroxyurea may be associated with an increased risk of acute leukaemia or myelodysplasia. Therefore alpha-interferon and anagrelide should be considered in younger patients. Early cytoreductive therapy is advocated in patients with idiopathic myelofibrosis (IMF) to inhibit further progression of bone marrow fibrosis and further expansion of myeloid metaplasia in the spleen and liver. Treatment with androgens (danazol) and glucocorticoids may improve severe anaemia and thrombocytopenia. In younger patients, allogeneic bone marrow transplantation should be considered.

[Acute thrombotic complication at the debute of the Philadelphia chromosome-negative myeloproliferative syndrome]

METHODS

We describe eight patients with a diagnosis of a chronic myeloproliferative disorder, characterised in most patients by severe thrombotic complications at the debut of the disease.

RESULTS

The symptoms were life-threatening in seven patients: acute upper gastrointestinal haemorrhage from oesophageal varices in four, an acute abdominal catastrophy owing to mesenteric vein thrombosis with intestinal gangrene in two, and a large cerebral infarction, which was lethal, in one. The same patient also suffered a thrombosis of the axillary and subclavian veins. Neurological symptoms, with headache, visual disturbances, dizziness, and impaired memory, were initial cardinal symptoms. In two patients, explorative laparotomy was performed with intestinal resection owing to gangrene. One patient had a toe amputation.

DISCUSSION

The above symptoms are explained by thrombosis in the microcirculation because of thrombocytosis and circulating platelet aggregates. In patients with polycythaemia vera, the elevated haematocrit contributes significantly to the impaired microcirculation. Early diagnosis and management of these disorders are of utmost importance to prevent the potentially life-threatening complications described above.

[The chronic Philadelphia chromosome-negative myeloproliferative syndrome I. Pathogenesis and pathophysiology]

In polycythaemia vera (PV) the erythroid progenitors proliferate autonomously independently of the circulating erythropoietin. The progenitors are hypersensitive to various growth factors, including insulin-like growth factor 1, which inhibits apoptosis in erythroid and myeloid progenitor cells. No change has been found in the erythropoietin (EPO) receptor. Thrombopoietin (Tpo) regulates the production of haematopoietic progenitor cells, particularly of platelets. By inhibiting apoptosis, this growth factor may be responsible for the autonomous proliferation of the megakaryocyte cell lineage in PV and idiopathic myelofibrosis (IMF), which are featured by highly elevated circulating Tpo levels. Thrombopoietin may also be involved in the pathogenesis of myelofibrosis and development of extramedullary haematopoiesis. Both fibrogenesis and angiogenesis in the bone marrow, spleen, and liver develop secondary to the release of various growth-promoting factors from the megakaryocyte cell lineage. The lesion of the pluripotent stem cell in PV and IMF seems to imply several defects, including lack of or decreased expression of the Tpo receptor, alterations in the sensitivity of progenitor cells to various growth factors, and alterations in important gene systems (Bcl-2), which govern cell survival. Essential thrombocytosis seems to be a heterogeneous disease entity, as about 50% of the patients have polyclonal haematopoiesis.

High prevalence of hyperhomocysteinemia due to marginal deficiency of cobalamin or folate in chronic myeloproliferative disorders

Hyperhomocysteinemia is an established risk factor for thrombosis. In patients with myeloproliferative disorders, thrombotic events are common. Our aim was to investigate whether the increased burden of proliferating cells present in these patients implies a risk of homocysteine (HCY) accumulation secondary to depletion of folate and/or cobalamin. Fifty patients (PV, 25; ET, 10; IMF, 15) and 163 healthy volunteers (HV) participated in the study. The prevalence of hyperhomocysteinemia was 56.0% in PV, 70.0% in ET, 60.0% in IMF, and 34.9% in HV. The mean P-homocysteine (P-HCY) was 13.88 +/- 4.24 micromol/L in PV, 12.78 +/- 3.70 in ET, 11.34 +/- 4.22 in IMF, and 9. 71 +/- 2.76 in HV. In PV and ET, but not in IMF, the mean P-HCY was significantly higher than in the HV group (P < 0.001, P = 0.028, and P = 0.163, respectively). Thirty-three percent of the patients with hyperhomocysteinemia displayed metabolic changes compatible with cobalamin deficiency (P-HCY and P-methylmalonic acid both elevated), while 67% were folate deficient (P-HCY elevated, P-methylmalonic acid normal). Supplementation therapy with the relevant vitamin was implemented in 11 vitamin-deficient patients and led to normalization of metabolite levels in all cases. No correlation between hyperhomocysteinemia and thrombosis was found. Our data indicate that patients with PV, ET, and IMF frequently develop hyperhomocysteinemia due to discrete depletion of cobalamin or folate. Vitamin therapy leads to normalization of P-HCY and should be considered, even though hyperhomocysteinemia does not seem to be of crucial importance for the thrombotic tendency in the myeloproliferative disorders.

Incidence, clinical features and outcome of essential thrombocythaemia in a well defined geographical area

In an attempt to characterise the clinical features, incidence and outcome of essential thrombocythaemia (ET) we report our experience in a large unselected series of patients from a well defined region. All new cases of ET in the County of Copenhagen were registered during the period 1977-98. We identified 96 cases of ET, yielding an age- and sex-adjusted annual incidence rate of 0.59/100.000 and a point-prevalence at last follow up of 11/100.000. The overall incidence rate was 0.31 and 1.00 per 100.000 population during the consecutive periods 1977-89 and 1990-98, respectively, corresponding to a 3.2-fold increase. Median age at diagnosis was 67 yr (females 68 yr, males 66 yr, range 18-87 yr), and the female to male (F/M) ratio was 2.6:1. At diagnosis, 52% of the patients displayed no ET-related symptoms and were discovered fortuitously by a routine platelet count. Forty-eight percent presented with thrombohaemorrhagic phenomena, of which microvascular disturbances of the central nervous system (CNS), extremities and skin were most frequently observed (23%). Compared to patients diagnosed after 1989, patients diagnosed before 1990 had a significantly higher mean platelet count, white blood cell (WBC) count, lactate dehydrogenase (LDH) value and alkaline phosphatase value. With a median follow up of 70 months, 5-yr survival was 76%, significantly lower than the expected survival of an age- and sex-matched control group (p = 0.0052). Thirty-seven patients experienced a total of 55 thrombohaemorrhagic events during follow-up, corresponding to an incidence of thrombosis and microvascular disturbances or haemorrhage of 8.1% per pt-yr and 2.5% per pt-yr, respectively. The number of patients experiencing thrombosis or microvascular disturbances was significantly higher among the 29 patients who never received acetylsalicylic acid (ASA) compared to the 67 patients who received ASA during follow up (45% vs. 21%; p = 0.017). This study provides population-based data suggesting the benefit of treatment with low-dose ASA in a non-selected population of patients with ET.

Increased platelet activation and abnormal membrane glycoprotein content and redistribution in myeloproliferative disorders

Chronic myeloproliferative disorders (MPDs) are characterized by a high incidence of thrombohaemorrhagic complications, possibly caused by platelet dysfunction. In an attempt to define platelet functional abnormalities, we assessed the expression of activation-dependent membrane proteins in unstimulated and agonist [ADP and thrombin receptor-activating peptide (TRAP)]-stimulated platelets using quantitative whole blood flow cytometry in samples from 50 MPD patients and 30 controls. The receptor densities of activation markers and glycoproteins (GPs) were quantified using standardized fluorescent beads. Compared with controls, the mean percentage of P-selectin-positive (15.3% vs. 7.2%; P < 0.001) and thrombospondin (TSP)-positive (6.6% vs. 3.7%; P = 0.003) platelets was increased in unstimulated platelets from patients. Patients having experienced a thrombotic event had a higher mean percentage of TSP-positive non-stimulated platelets than patients without a history of thrombosis (9.0% vs. 4.6%; P = 0.02) and a higher GPIV molecules of equivalent fluorochrome (MEF) value (33113 vs. 24471 MEF; P = 0.02). Mean MEF values of monoclonal antibodies (mAbs) against GPIb (34055 vs. 38945 MEF; P < 0.001) and GPIIb/IIIa (1416 vs. 1648 MEF; P < 0. 001) were significantly reduced among patients, whereas surface expression of GPIV was increased in patients (28273 vs. 16258 MEF; P < 0.001). In TRAP (10 micromol/l) stimulated whole blood, the MEF of P-selectin (9611 vs. 13293 MEF; P = 0.004) and CD63 (2385 vs. 5177 MEF; P < 0.001) and the ratio of PAC-1/GPIIb/IIIa MEF (0.98 vs. 2. 00; P < 0.001) was reduced in patients, indicating either a reduced granule GP content or an intrinsic cellular defect in receptor-mediated granule secretion and activation of the GPIIb/IIIa complex. Expressed as the relative change of MEF compared with unstimulated platelets, TRAP induced decrease of GPIb (7.8% vs. 45%; P < 0.001) and increase of GPIIb/IIIa (49.1% vs. 95.7%; P < 0.001) and GPIV expression (17.8% vs. 55.2%; P < 0.001) was attenuated in patients.

[Virus-associated hemophagocytic syndrome. Diagnosis and treatment]

Virus-associated haemophagocytic syndrome (VAHS) is a rare disease characterized by fever, splenomegaly, cytopenia and histiocytic proliferation with haemophagocytosis in the reticuloendothelial system. The clinical course of VAHS can be dramatic and the prognosis is often poor. The pathogenesis of VAHS is not well understood. Many believe that viral infection provokes an abnormal immune response in predisposed individuals leading to hyperactivation of Th1 helper cells, macrophage proliferation and secretion of large amounts of cytokines. The resultant hypercytokinaemia may be responsible for the clinical and biochemical manifestations of VAHS. In this article the clinical features, presumed pathogenesis, diagnostic criteria and treatment of VAHS are discussed.

["Blue rubber bleb nevus syndrome"--or Bean's syndrome]

We describe a case of the blue rubber bleb naevus syndrome, an uncommon systemic disorder characterized by multiple bluish haemangiomas of the skin and gastrointestinal tract. The syndrome is commonly associated with iron deficiency anaemia due to gastrointestinal bleeding. The syndrome is likely to be caused by a gene mapping to chromosome 9p and showing autosomal dominant inheritance. This is the first Danish report of this unusual disease. We hope that this case will heighten the awareness of this condition, because early recognition is essential for appropriate medical intervention and genetic counselling.

[Desmopressin in the treatment of hemorrhagic diathesis]

Over the past several years, the use of 1-deamino-8-D-arginine vasopressin (DDAVP), a synthetic analogue of vasopressin, has been found to be useful in the treatment of patients with abnormal bleeding tendency. This article is a review of inherited and acquired disorders with prolonged bleeding time in which DDAVP is supposed to shorten the bleeding time. DDAVP is established as effective therapy of the abnormal haemostasis in mild or moderate haemophilia A and von Willebrand's disease. Frequently, DDAVP infusions are used to control bleeding in patients with uraemia. Bleeding time is also significantly shortened in patients with liver cirrhosis, although randomized trials of DDAVP therapy of gastrointestinal bleeding in this group of patients are still needed. Shortening or normalization of the bleeding time with DDAVP has also been observed in patients with inherited platelet dysfunctions, acquired disorders of haemostasis and abnormal haemostasis in chronic myeloproliferative diseases. In addition, preoperative treatment with DDAVP seems to reduce blood loss during surgery.

Type III procollagen N-peptide correlates with beta-2-microglobulin in myelomatosis

The serum concentration of the N-terminal peptide of type III procollagen (PIIINP) was determined in 32 patients with myelomatosis (MM). Four subjects were studied at the time of diagnosis and the remaining patients at variable intervals from diagnosis. Serum concentration of beta-2-microglobulin (B2m) was measured in 31 patients. Serial measurements of both substances were performed in 20 patients. Serum PIIINP was increased in MM as compared with healthy control subjects (P < 0.001). Patients with active disease had significantly higher propeptide values (median 7.4; range 3.8-11.2) as compared to those with stable disease (median 4.3; range 2.2-9.6) (P < 0.009). A highly significant correlation existed between circulating PIIINP and B2m (P < 0.001). It is concluded that MM elicits a stromal reaction as reflected by parallel increases in serum PIIINP and serum B2m. In subsets of patients, e.g. those with non-secretory myeloma and in patients with smouldering disease, serum PIIINP may even be superior to B2m as an indicator of disease activity.

Idiopathic myelofibrosis--an update with particular reference to clinical aspects and prognosis

Idiopathic myelofibrosis (IMF) is characterized by excessive accumulation of connective tissue in the bone marrow as part of a clinical syndrome which in its classical form is featured by leukoerythroblastic anemia and huge splenomegaly at the time of diagnosis. An acute variant of the disease exists being featured by pancytopenia, nor or minimal splenomegaly and a rapidly fatal clinical course. This review describes the relationship of IMF to other chronic myeloproliferative disorders and highlights current concepts of the pathogenesis of bone marrow fibrosis, implicating the intramedullary release of various growth factors, including platelet-derived growth factor beta. In a subgroup of patients bone marrow fibrosis may develop consequent to autoimmune bone marrow damage. The clinical and laboratory findings in some of the larger series of patients are presented and the reasons for the highly variable clinical presentation and prognosis are critically discussed. It is proposed that studies on prognosis in IMF are based upon simple prognostic staging systems, which should include the Hb-concentration, platelet count, spleen size and the presence/absence of osteomyelosclerosis on X-ray. Using these parameters the patients are easily categorized into three prognostic groups with highly different survival times.

[Hematological changes associated with human immunodeficiency virus (HIV-1) infection]

Infection with human immunodeficiency virus type 1 (HIV-1) primarily involves a subgroup of T-lymphocytic cells, but other cell types are also invaded by the virus, including cell lines within the haematopoietic system. Together with infectious, inflammatory and neoplasic processes, invasion of haematopoietic tissue explains the haematological alterations which are seen during the course of infection with HIV-1. Anaemia develops in the large proportion of patients. Thrombocytopenia frequently occurs during the course of the disease, but may be seen in some patients already at the time of diagnosis, where the condition may be misdiagnosed as "idiopathic" thrombocytopenic purpura. Neutropenia is seen in all disease stages, but is most severe in patients with advanced disease. Bone marrow changes include varying degrees of dysplasia in one or more cell lines, which in some patients may mimic a myelodysplastic syndrome. The number of plasma cells is always increased. In many patients the bone marrow stroma exhibits an increased amount of reticular fibres. HIV-1 infection is associated with an increased risk of non-Hodgkin malignant lymphoma. Acute myelogenous leukaemia and myelomatosis have been described in patients with advanced disease. Treatment of the above mentioned haematological abnormalities aims primarily at reducing replication of HIV-1, thereby diminishing suppression of haematopoiesis by the virus infection, and at controlling the opportunistic infections during the course of the disease. Specific antiviral therapy (AZT) is most successful in correcting thrombocytopenia. The possibility of bone marrow suppression mediated by a toxic drug effect should always be considered in this patient group.

[Toxic shock syndrome in group A streptococcal infection]

Three new cases of toxic shock syndrome due to infection with group A beta-hemolytic streptococci are described and similar cases in the literature are reviewed. The typical features of this disease include rapid development of multiorgan failure with renal impairment and, in many patients, also the respiratory distress syndrome. Cardiac dysfunction with myocardial depression is a prominent feature which is most reasonably explained by an effect of the septicaemia per se but may also be toxic cardiomyopathy mediated by circulating toxins. Other major findings include exanthema--often with the development of haemorrhagic bullae as part of toxic epidermal necrolysis. In patients with initial soft tissue infection this is rapidly progressive and often associated with necrotizing fasciitis and myositis, which may give rise to a compartment syndrome with rhabdomyolysis. In addition to conventional therapy with antibiotics, fluid replacement and inotropics, most patients with extensive soft tissue infection also require surgical intervention with debridement and occasionally fasciotomy.

[Hematological abnormalities in alcoholism]

The most common haematological abnormalities in alcoholism are raised mean corpuscular volume of the erythrocytes and thrombocytopenia. The etiology is multifactorial including malnutrition with folate deficiency, a direct toxic influence of alcohol and sequestration in an enlarged spleen. Sideroblastic anaemia caused by interference of alcohol with the metabolism of pyridoxine is common and so is haemolytic anaemia caused by hypersplenism and megaloblastic anaemia. Leucopenia can be seen and is probably caused by a direct toxic effect of alcohol on the bone marrow. Other potentially toxic changes are impaired chemotaxis, motility and adherence of the granulocytes and impaired blast-transformation of the lymphocytes. In the bone marrow, vacuolized precursors of myelo- and erythropoiesis are seen. The bone marrow may be hypocellular. Other changes in the bone marrow are increased but ineffective erythropoiesis with defective iron metabolism, vacuolized pro-erythroblasts, multinucleated erythroblasts, megaloblasts and iron-containing plasma cells.

[Metabolic disorders in the treatment of malignant hematologic diseases--the acute tumor lysis syndrome]

The acute tumor-lysis syndrome is a potentially fatal complication which characteristically arises during initial chemotherapy of malignant hematological diseases with large tumor burdens. The syndrome is characterized by hyperphosphatemia, hypocalcemia, hyperuricemia and often acute renal failure. Prior to chemotherapy the patient should be treated for 12-24 hour with intensified diuresis to ensure optimal renal function. The treatment of the fully developed syndrome is hemodialysis. Three cases of TLS which developed during initial chemotherapy of patients with acute lymnphoblastic leukemia and non-Hodgkin lymphoma are presented.

Non-Hodgkin malignant lymphomas and Hodgkin's disease in first-degree relatives. Evidence for a mutual genetic predisposition?

The occurrence of malignant lymphomas in 3 siblings is described. The cases include the first report of Hodgkin's disease and non-Hodgkin malignant lymphoma in dizygotic twins. Another remarkable feature was the development of malignant lymphoma, when the siblings were at the same age. Although a transmissible agent or environmental factors cannot be excluded in this family, our observations may suggest a mutual genetic predisposition in Hodgkin's disease and non-Hodgkin malignant lymphoma.