Immune complexes in myelofibrosis: a possible guide to management

Patients with MPNs and retinal drusen show signs of complement system dysregulation and a high degree of chronic low-grade inflammation

BACKGROUND

The hematopoietic stem cell disorders, myeloproliferative neoplasms (MPNs), are characterised by chronic low-grade inflammation (CLI). Recently, we showed that patients with MPNs have an increased prevalence of drusen and age-related macular degeneration (AMD), and drusen prevalence seemed associated with higher CLI. Studying MPNs may reveal more about drusen pathophysiology. This study investigated CLI further by measuring cytokine levels and complement system markers, comparing these between patients with MPNs and AMD.

METHODS

This cross-sectional study, between July 2018 and November 2020 conducted at Zealand University Hospital (ZUH) - Roskilde, Denmark, included 29 patients with neovascular AMD (nAMD), 28 with intermediate-stage AMD (iAMD), 62 with MPNs (35 with drusen - MPNd and 27 with healthy retinas - MPNn). With flow cytometry, we measured complement-regulatory-proteins (Cregs). With immunoassays, we investigated cytokine levels combined into a summary-inflammation-score (SIS).

FINDINGS

The MPNd and nAMD groups had similar SIS, significantly higher than the MPNn and iAMD groups. Additionally, we found SIS to increase over the MPN biological continuum from early cancer stage, essential thrombocytaemia (ET), over polycythaemia vera (PV) to the late-stage primary myelofibrosis (PMF). MPNs showed signs of complement dysregulation, with Cregs expression lower in PV than ET and PMF and even lower in PV patients with drusen.

INTERPRETATION

This study suggests that MPNd have a higher CLI than MPNn and may indicate systemic CLI to play a greater part in, and even initiate drusen formation. We suggest using MPNs as a "Human Inflammation Model" of drusen development. The CLI in MPNs elicits drusen formation, triggering more CLI creating a vicious cycle, increasing the risk of developing AMD.

FUNDING

Fight for Sight, Denmark, and Region Zealand's research promotion fund.

Immune Complex Associated Glomerulonephritis in a Patient with Prefibrotic Primary Myelofibrosis: A Case Report

A case of prefibrotic myelofibrosis with immune complex-mediated glomerulonephritis is presented. A 45-year-old female, with history of right subclavian and axillary vein thrombosis, presented with abdominal distension, facial puffiness, and pedal edema. Evaluation revealed deranged renal functions with nephrotic range proteinuria and acute kidney injury. JAK2 mutation evaluated in view of portal vein thrombosis and splenomegaly was positive. Renal biopsy revealed mesangial proliferative glomerulonephritis with full house immune complex deposition on direct immunofluorescence (DIF). The patient had no signs or symptoms of systemic lupus erythematosus and serological markers for autoimmune or collagen vascular disease were negative. Renal involvement in myeloproliferative neoplasms (MPNs) is uncommon and histological patterns of DIF negative mesangial proliferative glomerulonephritis, focal segmental glomerulosclerosis, and immunoglobulin A nephropathy have been reported.

MPNs as Inflammatory Diseases: The Evidence, Consequences, and Perspectives

In recent years the evidence is increasing that chronic inflammation may be an important driving force for clonal evolution and disease progression in the Philadelphia-negative myeloproliferative neoplasms (MPNs), essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF). Abnormal expression and activity of a number of proinflammatory cytokines are associated with MPNs, in particular MF, in which immune dysregulation is pronounced as evidenced by dysregulation of several immune and inflammation genes. In addition, chronic inflammation has been suggested to contribute to the development of premature atherosclerosis and may drive the development of other cancers in MPNs, both nonhematologic and hematologic. The MPN population has a substantial inflammation-mediated comorbidity burden. This review describes the evidence for considering the MPNs as inflammatory diseases, A Human Inflammation Model of Cancer Development, and the role of cytokines in disease initiation and progression. The consequences of this model are discussed, including the increased risk of second cancers and other inflammation-mediated diseases, emphasizing the urgent need for rethinking our therapeutic approach. Early intervention with interferon-alpha2, which as monotherapy has been shown to be able to induce minimal residual disease, in combination with potent anti-inflammatory agents such as JAK-inhibitors is foreseen as the most promising new treatment modality in the years to come.

Immune derangements in patients with myelofibrosis: the role of Treg, Th17, and sIL2Rα

Myelofibrosis (MF), including primary myelofibrosis, post-essential thrombocythemia MF, and post-polycythemia vera MF, has been reported to be associated with autoimmune phenomena. IMiDs have been reported to be effective in some patients with MF, presumably for their immune-modulator effects. We therefore sought to elucidate the immune derangements in patients with MF. We found no differences in T regulatory cells (Treg) and T helper 17 (Th17) cells in MF patients and normal healthy controls. However, we found significantly elevated soluble interleukin 2 alpha (sIL2Rα) in MF patients compared to those with other myeloproliferative neoplasm diseases and normal healthy controls. Our studies with MF patients further revealed that Treg cells were the predominant cells producing sIL2Rα. sIL2Rα and IL2 complex induced the formation of Treg cells but not the formation of Th1 or Th17 cells. sIL2Rα induced CD8⁺ T cell proliferation in the presence of Treg cells. Monocytes or neutrophils had no effect on the production of sIL2Rα by Treg cells. Furthermore, we found plasma sIL2Rα levels were correlated to the auto-immune serology in MPN patients and ruxolitinib significantly inhibits the sIL2Rα production by the Treg cells in MF patients which may explain the effects of ruxolitinib on the relief of constitutional symptoms. All these findings suggest that sIL2Rα likely plays a significant role in autoimmune phenomena seen in patients with MF. Further studies of immune derangement may elucidate the mechanism of IMiD, and exploration of immune modulators may prove to be important for treating myelofibrosis.

A study of the cellular and humoral immune response in patients with myelofibrosis

There was evidence of impaired cellular immunity in 10 patients with myelofibrosis. In-vitro lymphocyte transformation with phytohaemagglutin, concanavalin A, and dinitrochlorobenzene skin reaction were diminished. Signs of impaired humoral activity were also found, the primary response to alpha-Helix pomatia haemocyanin being impaired, particularly in the immunoglobulin-A class. Moreover three patients had a benign paraproteinaemia. Immunecomplexes (IC) could be demonstrated with various test systems. The indirect granulocyte phagocytosis test was positive in 50%, the C1q-binding in 70% and the polyethylene glycol precipitation test in 50%. In most patients complement levels were normal, although the patient with the most advanced disease had low C3A, C3 and C4 levels accompanied by high levels of IC. No correlation could be shown between impaired immune response or levels of IC when they were related to spleen diameter or degree of anaemia. Some relation however existed between disturbed immune response and IC when they were related to time elapsed since diagnosis. It is suggested that the impaired immune response is the result of primary bone marrow disease and that the presence of IC may reflect the extent of fibrosis.

Myelofibrosis with myeloid metaplasia

MMM is a chronic myeloproliferative disorder characterized by bone marrow fibrosis and neoangiogenesis, constitutive release ofa high number of CD34+ stem cells from the bone marrow, and extramedullary hematopoiesis. It presents with heterogeneous clinical features in which anemia and progression to symptomatic splenomegaly dominate. The pathogenesis is undefined, but the dual action of deregulation of the bFGF pathway may influence myeloproliferation, myelofibrosis, and neoangiogenesis. Animal models suggest that chronic exposure to high doses of thrombopoietin or impairment of the capacity of megakaryocytes to differentiate into platelets, as occurs in the GATA-1(low) mice, is a necessary event for myelofibrosis. Allogeneic stem cell transplantation offers a chance of cure, and low conditioning regimens may extend the age of transplantable patients with lower mortality. Autologus stem cell transplantation and splenectomy are risky procedures that may be considered in patients with advanced disease when conventional therapies for correcting anemia (danazol, recombinant human erythropoietin, or cyclosporine) or chemotherapy for splenomegaly and myeloproliferation (hydroxyurea or interferon alfa) have failed. Thalidomide has been tested in numerous series, and its capacity to improve anemia and thrombocytopenia while reducing splenomegaly has been documented.

Idiopathic myelofibrosis associated with classic polyarteritis nodosa

A woman with scleroderma and classic polyarteritis nodosa (PAN) who developed idiopathic myelofibrosis (IM) is reported. The patient presented with a one-year history of weakness, polyarthritis, Raynaud phenomenon, dry cough, and epigastralgia. The diagnosis of scleroderma with visceral involvement was made and treatment with prednisone subsequently started, with good clinical response. Six years later, fever, weight loss, livedo reticularis, and dysesthesias developed. Electromyographic studies were consistent with sensory neuropathy and a sural nerve biopsy yielded the diagnosis of PAN. The patient received cyclophosphamide plus prednisone with a favorable response, but 11 years later she was admitted because of weakness, constitutional symptoms, and abdominal pain due to spleen infarcts. Marked anemia, with aniso-poikilocytosis, tear-drop cells, immature myeloid precursors in the peripheral blood, and an increased serum LDH, was observed and the diagnosis of IM established by bone marrow biopsy. This case represents a new association between IM and an autoimmune disease and supports the hypothesis of an immune basis of IM in some patients.

Idiopathic myelofibrosis associated with ulcerative colitis

A patient with ulcerative colitis (UC) who developed idiopathic myelofibrosis (IM) is reported. The initial diagnosis of UC was established by colonoscopy and large bowel biopsy, performed after a one-month history of abdominal pain and bloody diarrhea. The patient showed a favorable response to prednisone and mesalamine treatment and six months later he developed a new episode of UC, which was successfully controlled with treatment. However, two years later splenomegaly and anemia were observed, with aniso-poikilocytosis, tear-drop cells, immature myeloid precursors in the peripheral blood, and increased serum LDH, arising the suspicion of IM, a diagnosis that was confirmed by bone marrow biopsy. The present case represents a new association of IM with an autoimmune disease and gives support to the hypothesis of a possible immune basis of some IM cases.

Idiopathic myelofibrosis associated with primary biliary cirrhosis

A patient with primary biliary cirrhosis (PBC) who developed idiopathic myelofibrosis (IM) is reported. The initial diagnosis of PBC was established by liver biopsy, performed after a 2-month history of constitutional symptoms associated with abnormalities of the serum liver enzymes, with typical serum immunological markers being found. Although a favorable response of PBC to prednisone was observed, one and a half year later the patient developed anemia with anisocytosis and poikilocytosis, tear-drop cells, and leukoerythroblastic picture, and IM was diagnosed by bone marrow biopsy. A few months later, a rapid worsening of the patient's clinical condition was noted, with an increase in the constitutional symptoms and need for frequent packed RBC transfusions, and she finally died from an infectious complication. This case represents a new association of IM with an autoimmune disease, supporting the hypothesis of a possible immune basis of IM in some cases.

Myelofibrosis with myeloid metaplasia: diagnostic definition and prognostic classification for clinical studies and treatment guidelines

PURPOSE

Myelofibrosis with myeloid metaplasia (MMM) is a chronic myeloproliferative disorder characterized by bone marrow fibrosis and extramedullary hematopoiesis. Recent studies provide definite diagnostic criteria and prognostic classifications of the disease, and allogeneic stem-cell transplantation (SCT) now offers a chance of curing the disease. In order to put diagnostic criteria and prognostic classifications of the disease into the perspective of developing guidelines for treatment strategies, all studies published in the English literature over the last 30 years were reviewed.

MATERIALS AND METHODS

Studies were identified through a MEDLINE search (1966 to present) and from the bibliographies of relevant articles.

RESULTS

The Italian Consensus Conference on diagnostic criteria is a structured enterprise aimed at formulating a definition of MMM that will be used for enrolling patients onto clinical studies. It relies on the obligatory presence of myelofibrosis and on the exclusion of the BCR-ABL rearrangement or Philadelphia chromosome, in association with combinations of traditional features. Prognostic scores allow us to identify classes of patients on the basis of hemoglobin, age, WBC count, and chromosomal abnormalities. Several nonrandomized studies have indicated that allogeneic SCT for patients under the age of 55 is effective in prolonging survival in more than 50% of cases and in possibly curing the disease. Patients with the most severe prognosis are candidates.

CONCLUSION

"Consensus" methodology offers a definition of MMM useful for conducting and reporting clinical studies. A detailed knowledge of prognostic factors can help to delineate guidelines for addressing patients with allogeneic SCT.

Pediatric hyperfibrotic myelodysplasia: an unusual clinicopathologic entity

This study is presented to highlight a rare pediatric bone marrow pathology in which features of bone marrow dysplasia coexist with severe fibrosis in a clinical setting of fever, anemia, and organomegaly. Fourteen children (nine males, five females) clinically presented with fever, anemia, and hepatosplenomegaly. Extensive bone marrow fibrosis with dysplastic features was seen in their marrow precursor cells. Peripheral blood smears showed teardrop poikilocytes thrombocytopenia, and occasional blasts. In conclusion, pediatric hyperfibrotic myelodysplasia is a distinct clinicopathologic entity. Myeloproliferative and dysmyelopoietic syndromes are complex disorders that are interrelated and not always easily diagnosed only on morphologic grounds.

Evans' syndrome, myelofibrosis and systemic lupus erythematosus: role of procollagens in myelofibrosis

We describe an 18 yr old female with systemic lupus erythematosus presenting with Evans' syndrome (autoimmune hemolytic anemia and immune thrombocytopenia) and dense myelofibrosis. Her clinical course and response to treatment were monitored with regular blood counts, serial measurements of serum procollagen I and III and periodic bone marrow examinations. This report brings to 9 the number of well-documented cases of systemic lupus erythematosis and myelofibrosis in the literature; we discuss the pathogenesis and management of patients with this apparently rare disorder, with particular reference to the role of serum procollagen measurements as markers of myelofibrosis.

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.

Antibodies against terminal galactosyl alpha(1-3) galactose epitopes in patients with idiopathic myelofibrosis

Sera from patients with myelofibrosis were analysed for circulating antibodies against an antigenic determinant characterized by two molecules of galactose in alpha 1-3 linkage (anti-Gal antibodies). 50% of patients were found to have values above the 90th percentile of the values of control sera chosen as a cut-off. The median level of the antibodies was significantly higher than the value detected in normal controls, but no difference could be found between patients with idiopathic myelofibrosis and those with myelofibrosis associated to a chronic myeloproliferative disorder. Anti-Gal antibodies were found to correlate with disease activity and with platelet count whereas no correlation was detected with other haematological parameters. Furthermore, for evaluation of disease activity, determination of serum anti-Gal antibodies was a sensitive and specific parameter. We conclude that humoral immunity against Gal alpha 1-3Gal may provide a sensitive tool to detect disease activity in patients with idiopathic myelofibrosis and may be important for understanding its pathogenesis.

Idiopathic myelofibrosis: a clinical study of 80 patients

A series of 122 consecutive patients with bone marrow fibrosis initially referred or categorized as idiopathic myelofibrosis is described. After a clinical and pathological review 14 patients were classified as postpolycythaemic myelofibrosis and 7 patients as a transitional myeloproliferative disorder. In 13 patients a diagnosis of hairy cell leukaemia was made, 3 patients had malignant lymphoma, 2 had malignant histiocytosis, and 1 patient had systemic lupus erythematosus with myelofibrosis. Two patients were excluded for further analysis owing to insufficient data. In the remaining 80 patients a diagnosis of idiopathic myelofibrosis was made. The clinical and laboratory findings in this series of patients are presented and compared to those in previous series. Infectious, cardiovascular, thromboembolic, and haemorrhagic complications were frequent, being recorded in 63%, 50%, 40%, and 33% of the patients, respectively. Various autoimmune phenomena were found in a proportion of the patients, but none had clinical evidence of connective tissue disease. Fifteen patients (19%) had a syndrome of acute myelofibrosis. The diagnostic criteria for this disease entity and its place within the spectrum of myeloproliferative disorders are discussed. In the present series acute myelofibrosis was found to encompass various transitional stages toward the evolution of acute leukaemia. It is proposed that acute or malignant myelofibrosis is considered as an acute variant of idiopathic myelofibrosis. Within this syndrome the acute variant seems to be far more common than previously recognized, which may also explain the marked clinical heterogeneity of the myelofibrosis/osteomyelosclerosis syndrome in this and most previous series.

Circulating high molecular weight IgG fibronectin complexes in myeloproliferative disorders

The plasma of patients with myeloproliferative diseases was examined by polyethylene glycol (PEG) precipitation, analytical ultracentrifugation, and immunoaffinity chromatography for the presence of high molecular weight complexes of IgG and fibronectin. Abnormal circulating high molecular weight material was identified by ultracentrifugation in all patients. This was precipitated by PEG and was shown by exclusion chromatography to contain IgG in a high molecular weight form. Examination of plasma by immunoaffinity chromatography supported previous evidence for complex formation between IgG and fibronectin. These findings are further evidence that abnormal high molecular weight IgG complexes are a prominent feature of myeloproliferative disorders and implicate IgG fibronectin complex formation.

Myelofibrosis: a review of clinical and pathologic features and treatment

The purpose of this review is to discuss and clarify the current understanding of the pathogenesis, clinical manifestations, and treatment of MF. MF may be either a primary or secondary disorder. It is characterized by an increased deposition of bone marrow collagen, fibronectin, and laminin. Present evidence indicates that MF may be mediated by platelet or megakaryocyte growth factors, decreased prostaglandin mediated stem cell inhibition, immune complex deposition, and both fibroblast and endothelial cell proliferation. Recently acute MF has been recognized to be identical to acute megakaryocytic leukemia. Secondary MF usually responds to appropriate treatment of the underlying disease. Primary MF is usually treated by blood product support, but may be responsive to androgens, splenectomy, splenic irradiation, chemotherapy, or bone marrow ablation with marrow reconstitution.

Monoclonal gammopathy in chronic myeloproliferative disorders

The incidence of monoclonal gammopathy in 61 patients with chronic myeloproliferative disorders (CMPD) was studied. The distribution of patients among the CMPD subgroups was: chronic myelocytic leukemia, 24 patients; myelofibrosis, 11; polycythemia vera, 15; essential thrombocythemia, 7; unclassified MPD, 4 patients. Monoclonal gammopathy was found in 5 patients (8.2%). Two of these patients (1 IgA/k and 1 IgM/k) had myelofibrosis and 3 (2 IgG/k and 1 IgG/lambda) polycythemia vera. The presence of monoclonal gammopathy indicates an involvement of the lymphoplasmatic system in CMPD.

Histomorphometry of bone marrow biopsies in primary osteomyelofibrosis/-sclerosis (agnogenic myeloid metaplasia)--correlations between clinical and morphological features

Histomorphometry was performed on representative trephine biopsies of the bone marrow on admission of 50 patients (21 male, 29 female - age 67 years) with so-called primary osteomyelofibrosis/-sclerosis (OMF) not preceded by any other subtype of chronic myeloproliferative disorders. This study was firstly aimed at testing correlations between histological features (amount of haematopoiesis, cytological aspects of megakaryocytes, density of reticulin and collagen fibres and degree of osteosclerosis) and laboratory data, as well as spleen size and duration of relevant prediagnostic symptoms. Secondly, we concentrated on a discrimination of OMF patients into two subgroups according to bone marrow morphology and clinical variables. Statistical evaluation of histomorphometric variables and haematological findings disclosed that there was a progressive fibro-osteosclerotic process in the evolution of disease features. Increase in medullary fibrosis was significantly paralleled by an abnormal or pleomorphic megakaryopoiesis in the bone marrow: there was an increase in irregularity of perimeters for megakaryocytes and naked nuclei combined with smaller sizes of these elements including the nuclei. Additionally, there was a greater number of pycnotic bare nuclei. A number of morphometric features (density of fibres, degree of osteosclerosis, amount of haematopoiesis) were associated with corresponding clinical data (spleen size, length of preclinical history). By consideration of a set of basic histomorphometric variables our cohort of 50 patients could be divided into an early hyperplastic subtype with no or minimal medullary reticulin and another group with conspicuous fibrotic and osteosclerotic alterations of the bone marrow. It was noticeable that we found no significant correlation between amount of haematopoiesis or marrow cellularity with splenomegaly. This result suggests that splenic haematopoiesis (myeloid metaplasia) may represent an autonomous or neoplastic process and not only compensation for a failing fibro-osteosclerotic bone marrow.

Bone marrow lymphoid nodules in myeloproliferative disorders: association with the nonmyelosclerotic phases of idiopathic myelofibrosis and immunological significance

The presence of lymphoid nodules in bone marrow biopsy was investigated at diagnosis in 200 patients with chronic myeloproliferative disorders (MPD). Twelve out of 51 patients with idiopathic myelofibrosis (IM) showed such a feature (23.5%), versus two out of 100 with Ph1-positive chronic myeloid leukaemia, two of 32 with polycythaemia vera, and one of 17 with essential thrombocythaemia, the difference between IM and the remaining MPD being statistically significant (P less than 0.0001). When IM patients were compared for their initial characteristics according to the presence or not of bone marrow lymphoid nodules, patients with such a histological finding showed significantly lower values for either WBC counts, number of primitive cells in the blood, and serum lactic dehydrogenase levels. Moreover, it was observed that virtually all patients with lymphoid nodules were in the nonmyelosclerotic phases of IM. Finally, among the 14 of 32 IM patients (44%) investigated for circulating immune complexes who gave a positive test, a significant association between this immunological abnormality and bone marrow lymphoid nodules was found. The above results reinforce the immunological significance of the finding of bone marrow lymphoid nodules in IM and give support to the hypothesis of an immune component in the pathogenesis of the disorder.

Myelofibrosis: a concise review of clinical and pathologic features and treatment

This paper reviews and clarifies the current understanding of the clinical and pathologic features and treatment of MF. Recent investigations indicate that MF may be mediated by platelet- and megakaryocyte-derived growth factors, impaired prostaglandin-mediated stem cell growth inhibition, or excessive endothelial cell and fibroblast proliferation. Immunologic disorders have been associated with MF. MF may be either a primary or a secondary phenomenon. Secondary MF often regresses with appropriate treatment of this underlying disorder. Primary MF may require androgen therapy, splenectomy, splenic irradiation, bone curettage, chemotherapy, or bone marrow transplantation.

Angiofollicular lymph node hyperplasia associated with myelofibrosis case report and immunologic marker studies

A case of angiofollicular lymph node hyperplasia (AFH) (hyaline vascular type) of the mediastinum associated with myelofibrosis is reported with immune marker studies. We hypothesize that the myelofibrosis is more than a mere coincidence since other myeloproliferative disorders have been observed in conjunction with AFH. Immunohistochemistry on cryostat sections of lymph node using the biotin-avidin fluorescence technique showed the presence of numerous T helper cells and very few T suppressor/cytotoxic cells in the parafollicular areas. Concentric rings of lymphocytes showed the phenotype of mantle zone lymphocytes (i.e. IgM, IgD positivity), while the germinal centres were ill-formed as shown by Leu 14 (a Pan B cell marker) staining. By electron microscopy, follicular dendritic reticulum cells were readily found. The above findings suggest an abnormality of germinal center formation.

A reversible defect of platelet PDGF content in myeloproliferative disorders

Platelet PDGF (platelet derived growth factor), platelet associated IgG and plasma levels of circulating immune complexes were measured in patients with chronic myeloproliferative disorders (primary myelofibrosis, primary proliferative polycythaemia and essential thrombocythaemia). Platelet PDGF was low in 11/12 patients, immune complexes were elevated in 11/16, and PlAIgG was elevated in all 14 patients in whom it was measured. There was no significant correlation between platelet PDGF and plasma levels of immune complexes (r = -0.5, P greater than 0.1). Treatment with busulphan and prednisolone for 2-3 months restored normal levels of platelet PDGF and suppressed plasma immune complex levels. Plasmapheresis lowered levels of immune complexes but had no effect on platelet PDGF. These results indicate that the low platelet PDGF levels in chronic myeloproliferative disorders represent a reversible defect which is not directly related to the presence of immune complexes.

Composition of immune complexes and their relation to plasma fibronectin in chronic myeloproliferative disorders

High concentrations of circulating immune complexes were detected by polyethylene glycol precipitation in 11 of 20 patients with myelofibrosis secondary to chronic myeloproliferative disease. Circulating immune complexes showed a positive correlation with plasma IgG concentrations both in patients and controls. Covariance analysis of the two groups showed significantly increased polyethylene glycol precipitable IgG in patients when adjusted for plasma IgG concentrations, indicating that the patients had significantly increased concentrations of complexed IgG. The immune complexes contained IgG, C3, and fibronectin and were inversely correlated with plasma fibronectin concentrations, suggesting that this major non-specific opsonin is important for the normal clearance of immune complexes. Therapeutic plasmapheresis efficiently removed circulating complexes and produced an increase in plasma fibronectin. This suggests that plasmapheresis may be useful for controlling immune complex mediated complications of these disorders.

Systemic lupus erythematosus and myelofibrosis

Acute thrombocytopenia developed in a 27-year-old woman with systemic lupus erythematosus (SLE). Antibodies to red cells and granulocytes were identified in addition to an increase in platelet-associated IgG. Serum complement levels were reduced, circulating immune complexes were present, and high titers of antinuclear antibodies and antibodies to native DNA were demonstrated. Attempts to aspirate bone marrow were unsuccessful due to an increase in marrow reticulin. Treatment with corticosteroids reversed the thrombocytopenia but not the myelofibrosis or the serologic abnormalities. A review of the literature revealed four other patients, two men and two women, with SLE and myelofibrosis. In two of these patients, the myelofibrosis regressed following therapy with corticosteroids.

Immunological abnormalities in myelodysplastic syndromes. I. Serum immunoglobulins and autoantibodies

The immunoglobulin levels and autoantibody profiles of 104 patients with primary myelodysplastic syndromes (MDS), classified according to the FAB criteria, were analysed. Eight patients, four with coexistent non-Hodgkin's lymphomas, three with chronic lymphocytic leukaemia and one with a lymphoplasmacytoma, were excluded from the final analysis of immunoglobulin levels. Serum protein electrophoresis and immunoelectrophoresis revealed the presence of monoclonal gammopathy in 12 patients (12.5%). Of the remaining 84 patients, a polyclonal rise in serum immunoglobulins was present in 27 (32%) while a further 16 (19%) had low immunoglobulin levels. The direct antiglobulin test was positive in eight out of 98 patients tested (8.1%), and organ and non-organ specific autoantibodies were present in 15 out of 67 patients tested (22.3%). Two patients had associated pernicious anaemia (PA), two hypothyroidism, and one PA with hypothyroidism. Three patients had sero-negative rheumatoid arthritis. These results demonstrate that there is a high incidence of immunological abnormalities in MDS.

Increased growth and collagen synthesis of bone marrow fibroblasts from patients with chronic myelocytic leukaemia

Growth and collagen synthesis were measured in human bone marrow fibroblasts derived from patients with chronic myelocytic leukaemia (CML) and normal individuals. The 3H-thymidine uptake, growth rate and collagen synthesis of fibroblasts from patients with CML were significantly greater than those from normal subjects. Thus, there is increased proliferation and collagen synthesis of fibroblasts in patients with CML. These findings show that CML fibroblasts may display a greater sensitivity to stimulator contained in the fetal calf serum used for the cultures, and they are relevant to the myelofibrosis by bone marrow fibroblasts in this disease.

Immune abnormalities in myelodysplastic syndromes

The immune states of 52 patients with myelodysplastic syndromes classified according to the FAB criteria were studied. Serum electrophoresis and immunoelectrophoresis, direct Coombs test, and tests for organ and non-organ specific antibodies were performed. Twenty six patients had immunoglobulin abnormalities: six (11.5%) had monoclonal gammopathy; 17 (32.6%) had polyclonal increases in serum immunoglobulin; while in three (5.8%) immunoglobulin concentrations were decreased. The distribution of immunoglobulin abnormalities among the five myelodysplastic syndrome subtypes was fairly uniform. Results of direct Coombs test were negative in all cases. Organ specific antibodies were not detected in any of the patients tested, although two patients were found positive for antinuclear antibodies. The presence of immunoglobulin abnormalities indicates an involvement of the lymphoplasmatic system in myelodysplastic syndromes.

Circulating immune complexes in myelofibrosis

17 patients with idiopathic myelofibrosis were studied for the occurrence of circulating immune complexes (IC), using a polyethylene glycol complement consumption and a polyclonal rheumatoid factor inhibition assay. In 13 patients complement C3d was determined by rocket immunoelectrophoresis. Circulating IC were detected in 6 patients and were primarily found in patients with short duration of disease from time of diagnosis. The median duration of the disease in IC-positive patients was 4 months, compared to 12 months in the IC-negative group (P less than 0.05). 9 of the 13 patients investigated had increased levels of plasma C3d. However, there was no correlation to the occurrence of IC. It is concluded that circulating IC may take part in an immune-mediated bone marrow damage. This may involve deposition of IC in the bone marrow with secondary inflammation responsible for the development of bone marrow fibrosis.

Platelet-associated IgG and IgM in myelofibrosis

Elevated levels of platelet-associated IgG and/or IgM were found in 15 of 18 patients with myelofibrosis (83%). All but 5 patients with elevated PAIg had active disease. The amounts of PAIg were not correlated to either S-Ig, platelet count or spleen size. Levels of PAIgG well above the normal range were especially found in patients with short duration of disease and/or a transitional myeloproliferative state. It is debated whether immune-mediated platelet dysfunction may be of importance for the development of bone marrow fibrosis, mediated by the release of platelet-derived growth factors in the bone marrow. Elevated PAIg may also contribute to abnormal haemostasis and thrombocytopenia in myelofibrosis.

Red-cell sensitization in myelofibrosis

Using an enzyme-linked immunosorbent assay (ELISA), elevated RBC-Ig of the IgG and IgM class were found in 8 of 14 patients with idiopathic myelofibrosis. In 2 patients with high levels of RBC-Ig the direct Coombs' test was positive. It is supposed that immune haemolysis may contribute to the anaemia in some patients with idiopathic myelofibrosis.

Immune disorders in agnogenic myeloid metaplasia: relations to myelofibrosis

Tests for a dysimmune state were done in an unselected group of 67 patients with agnogenic myeloid metaplasia (AMM). The results were compared to those of 56 patients with polycythaemia vera (PV). 75% of AMM patients versus 32% of PV patients had various abnormalities. The most frequent disorders among AMM patients were serum antinuclear and anti smooth muscle autoantibodies (10.3% each), a positive test for rheumatoid factor (21.7%), a polyclonal increase in serum immunoglobulin levels (46.8%) or a serum monoclonal component (9.7%), a positive direct Coombs' test (19%), an anti I autoantibody (30%). In AMM patients there was no relationship between age, sex, importance of splenic enlargement, time from diagnosis or treatment and the present of a dysimmunity. Furthermore, in AMM patients, but also in PV patients, it seems that the more frequent and numerous these abnormalities the more severe is the myelofibrosis. Like other previous studies, these results suggest a lymphoid cell involvement in AMM and a role for these immune disorders in the pathogenesis of myelofibrosis.

Idiopathic myelofibrosis: a possible role for immune-complexes in the pathogenesis of bone marrow fibrosis

Sixteen patients with idiopathic myelofibrosis (IM) have been investigated with respect to the possibility that immune mechanisms may be of importance in the pathogenesis of bone marrow fibrosis. The following points appear relevant: (1) immune-complexes (IC) are detectable with different techniques in a high percentage of patients with IM. Their presence is associated with evidence of bone-marrow histological markers of immune activity. (2) IgG is the main Ig class in the composition of IM IC. The results obtained favour the hypothesis that autoimmune mechanisms are involved in IM patients.

Myelofibrosis in chronic granulocytic leukaemia

Serial trephine biopsies were performed in 45 cases of chronic granulocytic leukaemia (CGL) in order to determine the frequency and significance of secondary myelofibrosis in the evolution of the disease. Histological changes were graded 1-5b, ranging from no increase in reticulin to dense osteomyelosclerosis. Many cases showed a progressive increase from Grade 1 to Grade 3, and accelerated disease, or blast crisis, often supervened when Grade 3 changes were present. However, a significant number of cases showed Grade 4 and 5 changes, which were indistinguishable histologically from those found in agnogenic myeloid metaplasia (AMM) (idiopathic myelofibrosis), at the time of diagnosis. These patients did not always show a rapidly fatal course and may be considered as an example of 'transitional myeloproliferative disorder', with features intermediate between CGL and AMM.