Costas Tsatalas

Global Impairment of CD4+CD25+FOXP3+ Regulatory T Cells in Idiopathic Pulmonary Fibrosis

RATIONALE The implication of T cells in the pathogenesis of idiopathic pulmonary fibrosis (IPF) is controversial. CD4(+)CD25(+)FOXP3(+) regulatory T cells (Tregs) are pivotal in maintaining immune homeostasis, but their role in IPF pathophysiology has not yet been studied. OBJECTIVES To explore Treg dynamics and function in IPF. METHODS Treg levels and dynamics were analyzed by flow cytometry in the peripheral blood (PB) and bronchoalveolar lavage (BAL) of 21 patients with IPF, 35 patients with lung diseases other than IPF (patients without IPF), 20 patients with collagen vascular diseases with pulmonary parenchymal involvement (CVD-IP), and 28 healthy volunteers. The suppression of autologous CD4(+)CD25(-) cell-proliferative responses and cytokine release by magnetic bead-isolated Tregs was evaluated by proliferation assays and cytometric bead array. Correlations of Treg function and levels with lung function parameters were also performed. MEASUREMENTS AND MAIN RESULTS In patients with IPF, both BAL and PB Tregs were reduced compared with those of healthy volunteers and patients without IPF, although not always significantly. Treg levels were not affected by the administration of low-dose prednisone in four nonresponding patients. The suppressor potential of BAL and PB Tregs was compromised in patients with IPF and patients with CVD-IP, compared with healthy volunteers and patients without IPF. Similarly, the Treg-induced suppression of helper T-cell type 1 and 2 cytokine secretion was impaired in the BAL of patients with IPF and patients with CVD-IP. Moreover, the defective function of BAL Tregs correlated highly with parameters of disease severity. CONCLUSIONS This study provides the first evidence of global Treg impairment in IPF that strongly correlates with disease severity, suggesting a role for Tregs in the fibrotic process.

Kinetics, function and bone marrow trafficking of CD4+CD25+FOXP3+ regulatory T cells in myelodysplastic syndromes (MDS).

CD4+CD25+FOXP3+ T regulatory cells (Tregs) prevent autoimmunity by restricting overexuberant immune responses, but the same subpopulation can incur detrimental effects on antitumor responses. In both cases, the suppressor potential of Tregs appears to be strongly influenced by their compartmentalization. In myelodysplastic syndromes (MDS), immune deregulation and autoimmunity in the early stages might lead to ineffective hematopoiesis and bone marrow (BM) failure, whereas late-stage disease is characterized by the immune escape of the malignant clone. We show that these two stages of MDS are associated with differential Treg activity. Specifically, we found that in early stage MDS, compared with normal hematopoiesis and late stage MDS, Tregs are dysfunctional and their BM homing through the CXCL12/CXCR4 axis is seriously impaired as a result of CXCR4 downregulation. Conversely, in late stage MDS, Tregs are systemically and locally expanded and retain their function and migratory capacity. Moreover, Treg levels follow the disease course and are significantly reduced in treatment responding patients. Our findings indicate Treg involvement in the pathophysiology of MDS; defective suppressor function and BM trafficking of Tregs may be important in the autoimmune process of early MDS, but increased Treg activity could favor leukemic clone progression in late stage disease.

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.

PET/CT in primary mediastinal large B-cell lymphoma responding to rituximab-CHOP: An analysis of 106 patients regarding prognostic significance and implications for subsequent radiotherapy.

PET/CT in primary mediastinal large B-cell lymphoma responding to rituximab-CHOP: An analysis of 106 patients regarding prognostic significance and implications for subsequent radiotherapy

The Diagnostic Value of CD1d Expression in a Large Cohort of Patients With B-Cell Chronic Lymphoproliferative Disorders

Immunophenotyping is indispensable in the differential diagnosis of B-cell chronic lymphoproliferative disorders (B-CLPDs). However, B-CLPDs often show overlapping immunophenotypic profiles and may be diagnostically challenging. CD1d is an HLA class I-like molecule that presents glycolipids to invariant natural killer T cells. Normal mature B cells constitutively express CD1d, but with the exception of some conflicting data, its expression in B-CLPDs is unknown. We demonstrate that in 222 B-CLPD cases, CD1d expression of less than 45% is strongly predictive of CLL (likelihood ratio, 32.3; specificity, 97.4%; sensitivity, 84.1%). In addition, CD1d showed significantly higher staining intensity in splenic marginal zone lymphoma compared with atypical hairy cell leukemia, lymphoplasmacytic lymphoma, and mantle cell lymphoma, thus allowing the discrimination of the former from the latter immunophenotypically overlapping B-CLPDs. It is important to note that in a given patient, CD1d expression on malignant B cells was similar between tissues and remained unaffected by disease stage and treatment status. Our findings strongly argue for the incorporation of CD1d into routine lymphoma panels.

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)MPNs), 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)MPNs, 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.

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 (PhnegcMPD) 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.

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

Abstract. 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.

Effect of HbS in the determination of HbA2 with the Menarini HA-8160 analyzer and comparison with other instruments

It is known that the presence of hemoglobin S (HbS) affects the determination of hemoglobin A2 (HbA2) levels in clinical samples. We quantitated this effect using the Menarini HA‐8160 analyzer and compared with other instruments (HELENA beta‐thal quik column, TOSOH HLC‐723G7 and BIORAD Variant II) using the HELENA SAS‐MX alkaline gel electrophoresis kit as the reference method. The %HbA2 values from the HA‐8160 analyzer and the alkaline gel electrophoresis show a good linear correlation in the absence of HbS. A strong positive bias in the %HbA2 values from the HA‐8160 is apparent in the presence of HbS in the samples, when compared with the alkaline electrophoresis. The analytical imprecision and bias of the three HPLC instruments are comparable both in the presence and absence of HbS. The manual column method shows a lower bias in the absence of HbS but is more affected when HbS is present in the samples.