Bone marrow microvessel density and plasma angiogenic factors in myeloproliferative neoplasms: clinicopathological and molecular correlations.

Increased angiogenesis in BCR-ABL1 negative myeloproliferative neoplasms (MPNs) has been recognized, but its connection with clinical and molecular markers needs to be defined. The aims of study were to (1) assess bone marrow (BM) angiogenesis measured by microvessel density (MVD) using CD34 and CD105 antibodies; (2) analyze correlation of MVD with plasma angiogenic factors including vascular endothelial growth factor, basic fibroblast growth factor, and interleukin-8; (3) examine the association of MVD with clinicopathological and molecular markers. We examined 90 de novo MPN patients (30 polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET)) and 10 age-matched controls. MVD was analyzed by immunohistochemistry "hot spot" method, angiogenic factors by immunoassay and JAK2V617F, and CALR mutations by DNA sequencing and allelic PCR. MVD was significantly increased in MPNs compared to controls (PMF > PV > ET). Correlation between MVD and plasma angiogenic factors was found in MPNs. MVD was significantly increased in patients with JAK2V617F mutation and correlated with JAK2 mutant allele burden (CD34-MVD: ρ = 0.491, p < 0.001; CD105-MVD: ρ = 0.276, p = 0.02) but not with CALR mutation. MVD correlated with leukocyte count, serum lactate dehydrogenase, hepatomegaly, and splenomegaly. BM fibrosis was significantly associated with CD34-MVD, CD105-MVD, interleukin-8, and JAK2 mutant allele burden. JAK2 homozygote status had positive predictive value (100%) for BM fibrosis. Patients with prefibrotic PMF had significantly higher MVD than patients with ET, and we could recommend MVD to be additional histopathological marker to distinguish these two entities. This study also highlights the strong correlation of MVD with plasma angiogenic factors, JAK2 mutant allele burden, and BM fibrosis in MPNs.

Circulating immune complexes of calves with bronchopneumonia modulate the function of peripheral blood leukocytes: In vitro evaluation.

In this work we studied if circulating immune complexes (CIC) of calves with bronchopneumonia have the capacity to modulate function of peripheral blood leukocytes of healthy cattle. CIC of three month old calves (6 healthy and 6 diseased) were isolated by PEG precipitation. Peripheral blood mononuclear cells (MNCs) and granulocytes from healthy calves and cows were the CIC responder cells in in vitro tests. The most remarkable increase of adhesiveness to polystyrene and ROS synthesis (assessed by NBT test) was detected in cows' granulocytes stimulated with CIC of diseased calves. Results of MTT test showed that CIC of both healthy and diseased calves reduced granulocytes' viability. The strongest effect of inhibition of cows' granulocytes resulted from CIC of diseased calves. CIC only moderately reduced spontaneous viability of calves' MNCs. Again, the strongest effect of CIC isolated from diseased calves was observed. In contrast to the low impact of CIC on non-stimulated cells, their inhibitory effect on viability of mitogen stimulated MNCs was very strong. With CFSE assay we showed that both types of CIC stimulated spontaneous, but inhibited mitogen induced proliferation of calves' MNCs. Propidium iodide staining reviled that CIC increased apoptosis/necrosis of both non-stimulated and mitogen stimulated MNCs. CIC of both healthy and diseased calves modulated the function of peripheral blood MNCs and granulocytes, but a stronger effect of CIC of diseased calves was shown. The age of the donors (calves or cows) of the responder cells, and the activation state of these cells, were also of influence.

Proinflammatory Cytokine IL-6 and JAK-STAT Signaling Pathway in Myeloproliferative Neoplasms.

The recent JAK1/2 inhibitor trial in myeloproliferative neoplasms (MPNs) showed that reducing inflammation can be more beneficial than targeting gene mutants. We evaluated the proinflammatory IL-6 cytokine and JAK-STAT signaling pathway related genes in circulating CD34(+) cells of MPNs. Regarding laboratory data, leukocytosis has been observed in polycythemia vera (PV) and JAK2V617F mutation positive versus negative primary myelofibrosis (PMF) patients. Moreover, thrombocytosis was reduced by JAK2V617F allele burden in essential thrombocythemia (ET) and PMF. 261 significantly changed genes have been detected in PV, 82 in ET, and 94 genes in PMF. The following JAK-STAT signaling pathway related genes had augmented expression in CD34(+) cells of MPNs: CCND3 and IL23A regardless of JAK2V617F allele burden; CSF3R, IL6ST, and STAT1/2 in ET and PV with JAK2V617F mutation; and AKT2, IFNGR2, PIM1, PTPN11, and STAT3 only in PV. STAT5A gene expression was generally reduced in MPNs. IL-6 cytokine levels were increased in plasma, as well as IL-6 protein levels in bone marrow stroma of MPNs, dependent on JAK2V617F mutation presence in ET and PMF patients. Therefore, the JAK2V617F mutant allele burden participated in inflammation biomarkers induction and related signaling pathways activation in MPNs.

Evidence that calf bronchopneumonia may be accompanied by increased sialylation of circulating immune complexes' IgG.

Immune complexes (IC) could have an important role in the pathogenesis of pre-ruminant calves' bronchopneumonia. IC are potent activators of complement and neutrophils and they might be responsible for immune protection, as well as for pulmonary damage. Immunoglobulin G (IgG), as constituents of IC, initiates the effector phase of immune response through binding of Fcγ and complement receptors. The oligosaccharide moieties expressed on IgG can modulate their antigen affinity and effector function. Structural characteristics of IgG molecules from IC in the pre-ruminant calves have not been studied in detail. The aim of our study was to determine if the glycosylation profile of IgG from circulating IC (CIC) in calves with bronchopneumonia differed from those of healthy control calves. A total number of 13 Holstein-Friesian calves, at the age of three months were included in the study. All calves were clinically examined by a veterinarian. Calves were classified by signs of respiratory disease in two groups: healthy (n=6) and diseased (n=7) calves. The CIC from calves' sera were isolated by the polyethylene glycol precipitation (PEG) method. IgG molecules were isolated from PEG precipitates by Protein G affinity method. The level of expression and localization N-acetylglucosamine, galactose, sialic acid, and fucose within the isolated IgG was determined by lectin blot assay. Calves with bronchopneumonia had a statistically significantly increased level of CIC. IgG molecules were isolated from CIC of both healthy and diseased calves. Several other proteins in complex with IgG were detected in both groups of animals. The isolated IgG heavy chains of healthy calves expressed N-acetylglucosamine, galactose, sialic acid, and fucose. The light chains of IgG expressed N-acetylglucosamine, sialic acid, and fucose whereas galactose was not detected in healthy calves. In diseased animals, galactose was detected on light chains, and both heavy and light IgG chains were more sialylated. Proteins in complex with IgG were also lectin reactive, and their glycosylation in diseased animals was different compared to healthy controls. Increased sialylation is a characteristic of anti-inflammatory IgG. The increased sialylation of IgG from CIC in bronchopneumonia might be an attempt of immune system of calves to protect lung tissues against damages provoked by activated cells and secreted pro-inflammatory cytokines. At the same time, increased IgG sialylation could explain the inability of calves' immune system to initiate the process of antigen elimination by activation of Fcγ receptors.