Partial versus productive immunoglobulin heavy locus rearrangements in chronic lymphocytic leukemia: implications for B-cell receptor stereotypy.

The frequent occurrence of stereotyped heavy complementarity-determining region 3 (VH CDR3) sequences among unrelated cases with chronic lymphocytic leukemia (CLL) is widely taken as evidence for antigen selection. Stereotyped VH CDR3 sequences are often defined by the selective association of certain immunoglobulin heavy diversity (IGHD) genes in specific reading frames with certain immunoglobulin heavy joining (IGHJ ) genes. To gain insight into the mechanisms underlying VH CDR3 restrictions and also determine the developmental stage when restrictions in VH CDR3 are imposed, we analyzed partial IGHD-IGHJ rearrangements (D-J) in 829 CLL cases and compared the productively rearranged D-J joints (that is, in-frame junctions without junctional stop codons) to (a) the productive immunoglobulin heavy variable (IGHV )-IGHD-IGHJ rearrangements (V-D-J) from the same cases and (b) 174 D-J rearrangements from 160 precursor B-cell acute lymphoblastic leukemia cases (pre-B acute lymphoblastic leukemia [ALL]). Partial D-J rearrangements were detected in 272/829 CLL cases (32.8%). Sequence analysis was feasible in 238 of 272 D-J rearrangements; 198 of 238 (83.2%) were productively rearranged. The D-J joints in CLL did not differ significantly from those in pre-B ALL, except for higher frequency of the IGHD7-27 and IGHJ6 genes in the latter. Among CLL carrying productively rearranged D-J, comparison of the IGHD gene repertoire in productive V-D-J versus D-J revealed the following: (a) overuse of IGHD reading frames encoding hydrophilic peptides among V-D-J and (b) selection of the IGHD3-3 and IGHD6-19 genes in V-D-J junctions. These results document that the IGHD and IGHJ gene biases in the CLL expressed VH CDR3 repertoire are not stochastic but are directed by selection operating at the immunoglobulin protein level.

Th17 and Foxp3(+) T regulatory cell dynamics and distribution in myelodysplastic syndromes.

Foxp3(+) T regulatory cells (Tregs) and Th17 cells accumulate synchronously at tumor sites during cancer progression, where their interplay is apparently affecting the efficiency of the antitumor response. In myelodysplastic syndromes, a hematopoietic malignancy of myeloid origin, Tregs are highly increased in the late stages of the disease (L-MDS), but the mechanisms driving Treg expansion and the interaction between Treg and Th17 cell dynamics are still unknown. We demonstrate that the proliferative capacity of Tregs is deficient during the early MDS stages (E-MDS), while in L-MDS it returns to normal levels. In addition, synchronously to Treg expansion, L-MDS patients exhibit increased numbers of functionally competent bone marrow IL-17(+) and FOXP3(+)/IL-17(+) cells, in contrast to E-MDS patients, where Th17 cells are significantly decreased and hypofunctional. Our findings suggest similar kinetics of Treg and Th17 cells between MDS and solid tumors, indicating a common immune pathogenetic pathway between diverse cancer types.

Hydroxyurea (HU) is effective in reducing JAK2V617F mutated clone size in the peripheral blood of essential thrombocythemia (ET) and polycythemia vera (PV) patients.

Ph-negative chronic myeloproliferative disorders (Ph(neg)cMPD) are treated according to the estimated vascular risk. The recent discovery of V617F point mutation of the JAK2 kinase, which frequently occurs in these diseases, has not changed their management so far. However, emerging data tend to support a prothrombotic role for the mutation, along with a better response of JAK2V617F mutated patients to hydroxyurea treatment. Our data further support this notion.

Oxidised low-density lipoprotein and arterial function in beta-thalassemia major.

OBJECTIVES: Vascular abnormalities such as endothelial dysfunction and arterial stiffness have been described in patients with beta-thalassemia major (beta-TM). Increased concentrations of oxidised low-density lipoprotein cholesterol (oxLDL) have been observed in those patients, but possible associations between oxLDL and arterial function in beta-TM have not been defined. METHODS: Twenty-six patients (11 males) with beta-TM (age 23 +/- 4 yr) and 30 age and gender-matched healthy subjects were studied. Aortic stiffness was assessed by carotid-femoral pulse wave velocity (PWVc-f) using applanation tonometry; brachio-radial artery stiffness was assessed by carotid-radial PWV (PWVc-r). Flow-mediated dilatation (FMD) of the brachial artery and oxLDL (ELISA) were also measured. RESULTS: Patients with beta-TM had higher oxLDL levels (68.6 +/- 13.7 mU/mg vs. 50.0 +/- 12.6 mU/mg, P = 0.005), decreased FMD (3.6 +/- 2.5% vs. 7.3 +/- 3.5%, P = 0.001) and higher PWVc-f compared with controls (8.4 +/- 1.7 vs. 7.2 +/- 1.1. P < 0.002). FMD of the brachial artery was negatively associated with OxLDL concentrations in simple linear (r(2) = -0.25, P = 0.001) and multiple linear regression analysis (beta = -0.242, P = 0.03, R(2) = 0.43, P = 0.0002). PWVc-r was positively associated with OxLDL (r(2) = 0.23, P = 0.003) and showed a tendency in multiple regression analysis (beta = 0.18, P = 0.05). PWVc-r and FMD were also significantly correlated (beta = -0.213, P = 0.04) in beta-TM patients. There was no association between oxLDL and PWVc-f. CONCLUSION: An association between oxLDL, arterial elastic properties and endothelial dysfunction of muscular arteries was found. OxLDL may represent a contributing factor for the vascular manifestations described in beta-TM patients.

In vitro effects of the farnesyltransferase inhibitor tipifarnib on myelodysplastic syndrome progenitors.

BACKGROUND: Farnesyltransferase inhibitors (FTIs) target proteins needing prenylation for functioning. Tipifarnib (Zarnestra), a potent and specific inhibitor of farnesyltransferase, showed considerable activity in phase I and II studies in myelodysplastic syndrome (MDS), but the optimal regimen achieving high response rates with minor myelosuppression remains to be determined. Additionally, a direct effect on purified human MDS progenitors has not yet been shown. METHODS: MDS and normal CD34+ cells isolated by using immunomagnetic beads were plated for short-term cultures in semisolid media or liquid cultures for flow-cytometric assessment of apoptosis in the presence of either DMSO or various FTI concentrations. RESULTS: Tipifarnib exerted selective in vitro toxicity against clonal MDS hematopoiesis at concentrations less than 10 nM the effect being more prominent in white cell progenitors. This action was not due to apoptosis induction as both normal and MDS progenitors displayed equivalent DiOC3 and annexin V expression up to 72 h after exposure to tipifarnib. CONCLUSION: The leukemic clone is more susceptible in tipifarnib than normal progenitors. Since myelosuppression represents the main obstacle in the clinical use of tipifarnib in MDS, further reduction of the currently employed dose will potentially result in a more tolerable regimen without compromising its antileukemic action.

Dynamics of telomere's length and telomerase activity in Philadelphia chromosome negative myeloproliferative neoplasms.

Telomere exhaustion and increased telomerase activity are associated with the acquisition of aggressive molecular events in a variety of haematological malignancies. In Philadelphia chromosome negative myeloproliferative neoplasms (Ph(neg)MPN's), telomere dynamics during clonal evolution of these diseases have not yet been fully elucidated. Herein we demonstrated that telomere shortening is a global phenomenon in Ph(neg)MPN's, irrespective of disease phenotype, treatment administration and JAK2V617F mutational status but the presence of additional cytogenetic abnormalities further affects them. Consistent with the above finding, TA was upregulated in CD34+ haemopoietic progenitors from almost all Ph(neg)MPN subgroups compared to healthy donors. Moreover, TL below the cut-off value of 27% could predict disease progression in Ph(neg)MPN patients (PFS at 5 years 39% vs 81%). Thus, TL emerges as a new prognostic marker in Ph(neg)MPN, reflecting probably the genetic instability of highly proliferating MPN clones.

Regulation of hematopoiesis in vitro and in vivo by invariant NKT cells.

Invariant natural killer T cells (iNKT cells) are a small subset of immunoregulatory T cells highly conserved in humans and mice. On activation by glycolipids presented by the MHC-like molecule CD1d, iNKT cells promptly secrete T helper 1 and 2 (Th1/2) cytokines but also cytokines with hematopoietic potential such as GM-CSF. Here, we show that the myeloid clonogenic potential of human hematopoietic progenitors is increased in the presence of glycolipid-activated, GM-CSF-secreting NKT cells; conversely, short- and long-term progenitor activity is decreased in the absence of NKT cells, implying regulation of hematopoiesis in both the presence and the absence of immune activation. In accordance with these findings, iNKT-cell-deficient mice display impaired hematopoiesis characterized by peripheral-blood cytopenias, reduced marrow cellularity, lower frequency of hematopoietic stem cells (HSCs), and reduced early and late hematopoietic progenitors. We also show that CD1d is expressed on human HSCs. CD1d-expressing HSCs display short- and long-term clonogenic potential and can present the glycolipid alpha-galactosylceramide to iNKT cells. Thus, iNKT cells emerge as the first subset of regulatory T cells that are required for effective hematopoiesis in both steady-state conditions and under conditions of immune activation.

Effect of 4 weeks of basic military training on peripheral blood leucocytes and urinary excretion of catecholamines and cortisol.

In this study, we assessed the effects of a 4 week basic military physical training programme for male recruits of the Hellenic Air Force on the number and distribution of circulating immune cells and adrenergic and adrenocortical hormonal responses. One group of recruits (exercised, n = 48) participated in moderate intermittent physical exercise, whereas a second group (non-exercised controls, n = 9) performed only light work in the barracks. Both groups participated in the same non-physical, classroom-type training and testing. Military training by the exercised group resulted in significant increases in CD4+ T-lymphocytes, renal cortisol excretion and the urinary noradrenaline/adrenaline ratio, together with reductions in neutrophils and the neutrophil/lymphocyte ratio. In the exercised group, the urinary noradrenaline/adrenaline ratio correlated positively with the training-induced changes in CD4+ T-lymphocytes and negatively with changes in the neutrophil/lymphocyte ratio. No significant relationship was found between training-induced increases in cortisol excretion and any of the peripheral blood cell alterations. Our results indicate that 4 weeks of military training consisting of intermittent moderate exercise resulted in a significant increase in CD4+ T-lymphocytes and reduction in neutrophils. These changes were probably driven by alterations in hormonal status, including the significant impact of sympathetic nervous system activation.

Amifostine protects lymphocytes during radiotherapy and stimulates expansion of the CD95/Fas and CD31 expressing T-cells, in breast cancer patients.

A large body of experimental research supports the anti-neoplastic activity of cellular and humoral immunity. Disease and therapy-related immune suppression may be important on the treatment outcome or on the subsequent course of the malignant disease. The aim of the study was to investigate the efficacy of amifostine in preventing the immunological toxicity of post-operative radiotherapy (RT) in breast cancer patients. Using flow-cytometry, we examined comparatively the peripheral blood lymphocytic subpopulations in breast cancer patients undergoing conventional post-operative RT versus a hypofractionated accelerated RT scheme combined with amifostine (HypoARC) administration. Despite the higher radiation dose intensity delivered in the HypoARC group, a significant protection of CD4, CD8, CD19 and CD56 subtypes by amifostine was noted. We further focused on two interesting CD4/CD8 subpopulations involved in cellular apoptosis and trans-endothelial migration, namely the CD95/Fas and CD31 positive lymphocytes. Amifostine protected and induced expansion of these subtypes, which could contribute to the maintenance of a high burden of tumor infiltrating lymphocytes during therapy. It is suggested that amifostine effectively protects lymphocytes against RT, which may enhance the efficacy of the latter. The clinical impact of the CD95(+) and CD31(+) T-cell immunological modulation induced by amifostine requires further investigation.

Splenectomy for massive splenic infarction unmasks paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder characterized by pancytopenia, hemolysis, and thrombosis. Abdominal vein thrombosis is a life-threatening manifestation of this disease. We present a patient with complete spleen necrosis due to thrombosis of the splenic vessels. After splenectomy, other causes of thrombophilia were excluded and the diagnosis of PNH was established. The patient was put on anticoagulation but despite the prophylactic international normalized ratio maintained over the last 18 months of follow-up, he had another episode of intrahepatic thrombosis which was treated with tissue plasminogen activator thrombolysis.

Amifostine stimulates the formation of hematopoietic bone marrow progenitors from B-cell chronic lymphocytic leukemia.

Amifostine is a phosphorylated aminothiol that not only protects hematopoietic progenitor cells from chemotherapy and radiotherapy, but also stimulates normal hematopoiesis. The effect of amifostine on the in vitro growth of hematopoietic progenitors derived from B-cell chronic lymphocytic leukemia(B-CLL) was investigated. The colony-forming units (CFU)-granulocyte macrophage (CFU-GM), the burst-forming units-erythroid (BFU-E) and the CFU-granulocyte erythroid macrophage megakaryocytes (CFU-GEMM) increased 38, 20 and 100%, respectively, after the incubation with amifostine. There was no statistical difference in the in vitro progenitor growth of patients grouped according to their disease stage, bone marrow lymphocytic infiltration or therapy. Our data indicate that apart from cytoprotection the parallel use of amifostine and chemotherapy in patients with B-CLL could enhance bone marrow recovery.