Immune complexes in myeloproliferative disorders

Targeted Metabolomics Highlights Dramatic Antioxidant Depletion, Increased Oxidative/Nitrosative Stress and Altered Purine and Pyrimidine Concentrations in Serum of Primary Myelofibrosis Patients

To date, little is known concerning the circulating levels of biochemically relevant metabolites (antioxidants, oxidative/nitrosative stress biomarkers, purines, and pyrimidines) in patients with primary myelofibrosis (PMF), a rare form of myeloproliferative tumor causing a dramatic decrease in erythropoiesis and angiogenesis. In this study, using a targeted metabolomic approach, serum samples of 22 PMF patients and of 22 control healthy donors were analyzed to quantify the circulating concentrations of hypoxanthine, xanthine, uric acid (as representative purines), uracil, β-pseudouridine, uridine (as representative pyrimidines), reduced glutathione (GSH), ascorbic acid (as two of the main water-soluble antioxidants), malondialdehyde, nitrite, nitrate (as oxidative/nitrosative stress biomarkers) and creatinine, using well-established HPLC method for their determination. Results showed that PMF patients have dramatic depletions of both ascorbic acid and GSH (37.3- and 3.81-times lower circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001), accompanied by significant increases in malondialdehyde (MDA) and nitrite + nitrate (4.73- and 1.66-times higher circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001). Additionally, PMF patients have remarkable alterations of circulating purines, pyrimidines, and creatinine, suggesting potential mitochondrial dysfunctions causing energy metabolism imbalance and consequent increases in these cell energy-related compounds. Overall, these results, besides evidencing previously unknown serum metabolic alterations in PMF patients, suggest that the determination of serum levels of the aforementioned compounds may be useful to evaluate PMF patients on hospital admission for adjunctive therapies aimed at recovering their correct antioxidant status, as well as to monitor patients' status and potential pharmacological treatments.

Clonal haematopoiesis and dysregulation of the immune system

Age-related diseases are frequently linked to pathological immune dysfunction, including excessive inflammation, autoreactivity and immunodeficiency. Recent analyses of human genetic data have revealed that somatic mutations and mosaic chromosomal alterations in blood cells - a condition known as clonal haematopoiesis (CH) - are associated with ageing and pathological immune dysfunction. Indeed, large-scale epidemiological studies and experimental mouse models have demonstrated that CH can promote cardiovascular disease, chronic obstructive pulmonary disease, chronic liver disease, osteoporosis and gout. The genes most frequently mutated in CH, the epigenetic regulators TET2 and DNMT3A, implicate increased chemokine expression and inflammasome hyperactivation in myeloid cells as a possible mechanistic connection between CH and age-related diseases. In addition, TET2 and DNMT3A mutations in lymphoid cells have been shown to drive methylation-dependent alterations in differentiation and function. Here we review the observational and mechanistic studies describing the connection between CH and pathological immune dysfunction, the effects of CH-associated genetic alterations on the function of myeloid and lymphoid cells, and the clinical and therapeutic implications of CH as a target for immunomodulation.

Expression profile analysis reveals hub genes that are associated with immune system dysregulation in primary myelofibrosis

OBJECTION

Primary myelofibrosis (PMF) is a familiar chronic myeloproliferative disease with an unfavorable prognosis. The effect of infection on the prognosis of patients with PMF is crucial. Immune system dysregulation plays a central role in the pathophysiology of PMF. To date, very little research has been conducted on the molecular mechanism of immune compromise in patients with PMF.

METHODS

To explore potential candidate genes, microarray datasets GSE61629 and 26049 were obtained from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between PMF patients and normal individuals were evaluated, gene function was measured and a series of hub genes were identified. Several significant immune cells were selected via cell type enrichment analysis. The correlation between hub genes and significant immune cells was determined.

RESULTS

A total of 282 DEGs were found, involving 217 upregulated genes and 65 downregulated genes. Several immune cells were found to be reduced in PMF, such as CD4⁺ T cells, CD4⁺ Tems, CD4⁺ memory T cells. Gene Ontology (GO) enrichment analysis of DEGs reflected that most biological processes were associated with immune processes. Six hub genes, namely, HP, MPO, MMP9, EPB42, SLC4A1, and ALAS2, were identified, and correlation analysis revealed that these hub genes have a negative correlation with immune cell abundance.

CONCLUSIONS

Taken together, the gene expression profile of whole blood cells in PMF patients indicated a battery of immune events, and the DEGs and hub genes might contribute to immune system dysregulation.

Identification of Potential Key Genes and Regulatory Markers in Essential Thrombocythemia Through Integrated Bioinformatics Analysis and Clinical Validation

Introduction

Essential thrombocytosis (ET) is a group of myeloproliferative neoplasms characterized by abnormal proliferation of platelet and megakaryocytes. Research on potential key genes and novel regulatory markers in essential thrombocythemia (ET) is still limited.

Methods

Downloading array profiles from the Gene Expression Omnibus database, we identified the differentially expressed genes (DEGs) through comprehensive bioinformatic analysis. GO, and REACTOME pathway enrichment analysis was used to predict the potential functions of DEGs. Besides, constructing a protein–protein interaction (PPI) network through the STRING database, we validated the expression level of hub genes in an independent cohort of ET, and the transcription factors (TFs) were detected in the regulatory networks of TFs and DEGs. And the candidate drugs that are targeting hub genes were identified using the DGIdb database.

Results

We identified 63 overlap DEGs that included 21 common up-regulated and 42 common down-regulated genes from two datasets. Functional enrichment analysis shows that the DEGs are mainly enriched in the immune system and inflammatory processes. Through PPI network analysis, ACTB, PTPRC, ACTR2, FYB, STAT1, ETS1, IL7R, IKZF1, FGL2, and CTSS were selected as hub genes. Interestingly, we found that the dysregulated hub genes are also aberrantly expressed in a bone marrow cohort of ET. Moreover, we found that the expression of CTSS, FGL2, IKZF1, STAT1, FYB, ACTR2, PTPRC, and ACTB genes were significantly under-expressed in ET (P<0.05), which is consistent with our bioinformatics analysis. The ROC curve analysis also shows that these hub genes have good diagnostic value. Besides, we identified 4 TFs (SPI1, IRF4, SRF, and AR) as master transcriptional regulators that were associated with regulating the DEGs in ET. Cyclophosphamide, prednisone, fluorouracil, ruxolitinib, and lenalidomide were predicted as potential candidate drugs for the treatment of ET.

Discussion

These dysregulated genes and predicted key regulators had a significant relationship with the occurrence of ET with affecting the immune system and inflammation of the processes. Some of the immunomodulatory drugs have potential value by targeting ACTB, PTPRC, IL7R, and IKZF1 genes in the treatment of ET.

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.

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.

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.

Plasma soluble interleukin-2 receptor in patients with primary myelofibrosis

Using en enzyme-linked immunosorbent assay (ELISA) test, the level of soluble Tac peptide, one chain of the human interleukin-2 receptor, was measured in the plasma of 26 patients with primary myelofibrosis (MF), seven patients with polycythaemia vera and 11 normal controls. The plasma soluble interleukin-2 receptor (sIL-2R) was found to be significantly elevated in patients with primary MF compared to polycythaemia vera or controls (P < 0.001), while the plasma sIL-2R of patients with polycythaemia vera also was found to be significantly elevated compared to controls (P < 0.01). The significantly elevated value of sIL-2R seen in primary MF may be secondary to T cell activation resulting from autoimmune phenomena, and myeloblast activation with release of sIL-2R may also be a contributing factor. In primary MF, plasma sIL-2R levels were also found to be correlated to survival, circulating blast cell counts, and thrombocytopenia, but not to white blood cell counts, LDH levels, degree of marrow fibrosis, or degree of splenomegaly. Patients with primary MF with higher titre of plasma sIL-2R had a shorter survival. Further studies involving more patients and longer follow-up may substantiate that plasma sIL-2R is an important prognostic indicator in primary MF.

Vasculitic skin ulcers associated with myelofibrosis--a case report

This is the case report of a seventy-seven-year-old woman with ulcerated skin vasculitis of the lower extremities that preceded the appearance of myelofibrosis. No previous report of this association has been found in a survey of the literature.

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.

Bone growth and haemopoiesis: steroid reversible anaemia, myelofibrosis and increased bone formation in a child

Factors regulating the interaction between bone marrow haemopoietic cells, stromal elements and bone growth are poorly understood. Disturbance in the equilibrium between these elements can occur as the result of metabolic bone disease, haematologic disorders, neoplasia and infections. The present report concerns a child with myelofibrosis, hypoplastic/dyserythropoietic anaemia, osteoblast proliferation and increased bone formation. A positive tuberculin skin test and elevated EB virus titre indicated previous exposure to Mycobacterium tuberculosis and Epstein-Barr virus. No active focus of infection was identified and no improvement occurred following anti-tuberculous therapy. A dramatic improvement occurred on corticosteroid therapy. Reticulocytosis was followed by an increase in haemoglobin and platelets and a decrease in ESR. Bone marrow fibrosis resolved and the marrow was repopulated with normal haemopoietic tissue. The bone abnormalities improved both radiologically and histomorphometrically. Relapse occurred when steroids were discontinued. Bone marrow tissue culture supernate from the patient during the active phase of the disease inhibited colony formation by normal marrow mononuclear cells. This was reversed by steroid therapy. It is postulated that EB virus may have triggered osteoblast proliferation with resultant bony and haematologic changes. Response to corticosteroids could be explained on the basis of suppression of osteoblast activity and correction of fibroblast mediated suppression of haemopoiesis.

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.

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.

Chronic myeloproliferative disorders (CMPD)

The wide clinical range of CMPD can be understood as leukaemia of pluripotent stem cells according to the pathogenic concepts reviewed above. Blastic metamorphoses of CMPD are regressions to a more primitive level of cellular differentiation. The predominant proliferative cell line characterizes the classical entities of PV, PT and CML, and their different prognoses. Pure erythrocytic and megakaryocytic proliferations are more compatible with sustained physiologic bone marrow functions than granulocytic proliferations. The combinations of granulocytic and megakaryocytic growth are especially prone to develop MF/OMS, in which participation of immune reactions, of granulocytic and of platelet factors is probable. An etiologic role for ineffective thrombocytopoiesis is supported by experimental as well as by histologic evidence. Myelofibrosis and osteomyelosclerosis may have similar causes, but develop independently. The prevalence of the female sex among thrombocythaemic patients was proven statistically also for the increase of giant type megakaryocytes in the form of clusters in the bone marrow, and for longer median survival of females in CMPD, especially when there is megakaryocytosis in the bone marrow. It is assumed that females may be better protected against the detrimentous effects of abnormal platelet production. An arbitrary classification according to haematologic and histologic criteria was applied to PV, PT and CML, and groups with typical and atypical haematologic and histologic signs were distinguished. The latter cannot be separated from each other by their various haematologic manifestations, but by histology and their different propensity to progress into more immature and/or fibrotic stages. Three major groups are characterized by histology: mixed granulocytic-megakaryocytic myelosis with giant megakaryocytic clusters, a similar variant with diffuse distribution of giant megakaryocytes, and immature and/or pleomorphic megakaryocytic myelosis. Transitions from each of these groups have been observed as well as transitions from each of the typical CMPD-entities into these less typical forms. CML, frequently accompanied by dwarf-megakaryocytes, often develops into pleomorphic megakaryocytic or blastic myelosis. Blastic dedifferentiation and myelofibrosis manifest themselves as closely related end stages, to which principally all groups proceed after a longer or shorter period of time, modified by the proliferating cell lines in each group. Clinical, experimental and histologic evidence of this natural history has been reviewed, with special emphasis on the re-evaluation of technically optimal bone marrow biopsies of untreated patients.(ABSTRACT TRUNCATED AT 400 WORDS)

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.

Transition of myelofibrosis to polycythaemia vera

A case of typical myelofibrosis with a huge spleen is described in a 62-year old man. During the subsequent 2-year follow-up, a clinical picture of polycythaemia vera with pancytosis and disappearance of the marrow fibrosis was observed. The pancytosis necessitated treatment with busulphan and frequent phlebotomies. The transformation was associated with prednisone treatment for a suspected haemolytic state. During this treatment, the spleen no longer became enlarged on clinical palpation, although it was still enlarged at post mortem examination, but much less than 2 years earlier.

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.

Platelet Fc receptor. Increased expression in myeloproliferative disease

The platelet Fc receptor, a membrane receptor for immune complexes or aggregated immunoglobulin (Ig)G, was compared in normal and myeloproliferative platelets. Washed platelets from 11 normal donors and 27 patients were incubated with fluorescein-conjugated ovalbumin-anti-ovalbumin complexes and examined by phase and fluorescence microscopy. Only 3.2+/-1% of the normal platelets stained, whereas 76+/-16% of the myeloproliferative platelets stained with the immune complex. The fluorescent staining was mediated by a platelet Fc receptor, as shown by the absence of platelet staining with immune complex containing antibody preincubated with Staphylococcal protein A to block the Fc region. In addition, no staining occurred with antigen or antibody alone or after preincubation of platelets with aggregated IgG. Platelets from normal or myeloproliferative donors did not stain with the immune complexes when the incubation was performed in plasma. The increased expression of Fc receptors on myeloproliferative platelets was corroborated by studies of [(14)C]serotonin release by immune complexes or aggregated IgG in 8 patients and 17 normal donors. Serotonin uptake was similar in both groups. Myeloproliferative platelets released significantly more serotonin than normal platelets at each concentration of immune complex or aggregated IgG; in addition, myeloproliferative platelets released serotonin in response to much smaller concentrations of immune complex or aggregated IgG. [(14)C]Serotonin release by myeloproliferative platelets was not increased above that of normal platelets when thrombin was used as the stimulus. The results were independent of patient age, sex, therapy, hematocrit, or platelet size. Interaction of circulating immune complexes with platelets bearing increased Fc receptors may contribute to the abnormal hemostasis associated with the myeloproliferative syndromes.

Impaired neutrophil function and myeloperoxidase deficiency in pregnancy

The ability of neutrophils to phagocytose and kill Candida guilliermondii was investigated in 28 pregnant women and compared wtih 29 healthy controls. Phagocytosis was normal, but the ability to kill and digest Candida was reduced to 65% of normal. Quantitative myeloperoxidase measurement revealed a considerable reduction of this enzyme (55% of normal) while neutrophil alkaline phosphatase levels were nearly twice as high as in normals. It is suggested that both lack of myeloperoxidase and impaired candidacidal ability result from the discharge of the neutrophil's granules during previous phagocytosis of antibody-antigen complexes in the circulation.