Proliferative characteristics of Philadelphia-negative myeloproliferative neoplasms - clinical implications.

INTRODUCTION: Philadelphia-negative myeloproliferative neoplasms (Ph- MPN) are characterized by overproduction of one or more blood cell lines. METHODS: We studied the proliferative characteristics of 91 patients with de novo Ph- MPN. Colony-forming cells (CFC) and endogenous colonies (EC), from bone marrow (BM) and/or peripheral blood (PB), were analyzed by colony assay based on methylcellulose. The level of circulating CD34+ cells was determined by flow cytometry. RESULTS: The total number of PB CFC in primary myelofibrosis (PMF) was increased compared to the control sample (P < 0.01) and essential thrombocythemia (ET) (P < 0.05). The highest number of BM and PB EC was observed in polycythemia vera (PV) (P < 0.01). Increased levels of CD34+ cells characterized early-prefibrotic (57%) and advanced-fibrotic PMF (90%) as compared to PV (34%) and ET (32%) (P < 0.01). In the whole Ph- MPN group, the total number of PB CFC (P < 0.01), PB EC (P < 0.05), and CD34+ cells (P < 0.01) correlated with the degree of BM fibrosis. Higher levels of circulating CD34+ cells in PMF correlated with the total number of PB EC (P < 0.05) and degree of BM fibrosis (P < 0.01). CONCLUSIONS: Exploration of the PB proliferative characteristics of Ph- MPN on diagnosis may be helpful in revealing early-prefibrotic PMF. Monitoring the levels of circulating CD34+ cells may provide a sensitive indicator of fibrotic evolution in PV and PMF.

Glucocorticoid receptor mediates the expansion of splenic late erythroid progenitors during chronic psychological stress.

Stress evokes an integrated neuroendocrine response perturbing the homeostasis of different physiological systems. In contrast to well established physiologica linteractions between neuroendocrine and immune systems during chronic stress, there has been relatively little information on the effects of psychological stress on erythroid cells. Since stress-induced erythropoiesis occurs predominantly in the spleen, in the current study, we investigated the influence of chronic psychological stress on splenic erythroid progenitors and examined a role of glucocorticoid receptor (GR) in observed effect using a mouse model of restraint. The adult male mice were subjected to 2 hours daily restraint stress for 7 or 14 consecutive days and the role of GR in erythropoietic response to stress was assessed by pretreatment of mice with GR antagonist mifepristone 60 min prior to restraint. The results showed that chronic restraint stress induced an increase in spleen weight as well as in the cellularity of red pulp, as compared to controls. Furthermore, 7 and 14 days of restraint stress resulted in markedly increased number of both splenic early (BFU-E) and late (CFU-E) erythroid progenitors. Blockade of GR with mifepristone did not affect the number of BFU-E in stressed mice, but it completely abolished the effect of repeated psychological stress on CFU-E cells. Additionally, plasma corticosterone concentration was enhanced whereas the GR expression was significantly decreased within splenic red pulp after one and two weeks of stress exposure. Obtained findings suggest for the first time an indispensable role for GR in the expansion of CFU-E progenitors in the spleen under conditions of chronic psychological stress.

Serum interleukin-17 & nitric oxide levels in patients with primary Sjögren's syndrome.

BACKGROUND & OBJECTIVES: The interleukin (IL)-17 producing T-helper cells have been linked to pathogenesis of autoimmunity and mostly investigated in rheumatoid arthritis (RA). In this study we tested the IL-17 levels, as well as the levels of nitric oxide (NO) as possible IL-17-induced product, in patients with primary Sjögren's syndrome (pSS), an intricate and complex chronic autoimmune disorder of exocrine glands. METHODS: Serum IL-17 levels and nitrite concentrations determined in patients with pSS (n=30) were compared with the values obtained in patients with RA (n=10) and healthy controls (n=15). The values obtained for IL-17 in pSS patients were also associated with the patients' clinical characteristics, particularly the rheumatoid factor (RF) and total antinuclear antibodies (tANA) levels. RESULTS: Serum concentrations of IL-17 were significantly (P<0.01) higher in patients with pSS (12.9 ± 28.0 pg/ml) as compared to those obtained in healthy individuals (0.2 ± 0.6 pg/ml), but not as high as the values obtained for the patients with RA (34.5 ± 56.2 pg/ml). The mean IL-17 levels were significantly (P<0.05) higher in the pSS patients positive for rheumatoid factor (20.3 ± 33.3 pg/ml) than in RF-negatives (0.3 ± 0.6 pg/ml). Mean serum concentrations of IL-17 were also higher in antinuclear antibody (ANA)-positive samples (19.8 ± 33.5 pg/ml) in comparison to ANA-negative sera (1.1 ± 3.1 pg/ml) (P<0.05). The NO levels also showed elevated values in both pSS and RA patients, as compared to the healthy controls, since mean nitrite levels in patients with pSS and RA were 38.2 ± 29.2 µM and 41.7 ± 21.1 µM, respectively, while those in healthy controls were significantly lower, at 19.2 ± 10.5 µM. INTERPRETATION & CONCLUSIONS: The findings of this study showed that there was increased IL-17 and NO production in patients with primary SS, especially if they had associated elevated rheumatoid factor and antinuclear antibody values.