Mature CD10+ and immature CD10- neutrophils present in G-CSF-treated donors display opposite effects on T cells.

The identification of discrete neutrophil populations, as well as the characterization of their immunoregulatory properties, is an emerging topic under extensive investigation. In such regard, the presence of circulating CD66b+ neutrophil populations, exerting either immunosuppressive or proinflammatory functions, has been described in several acute and chronic inflammatory conditions. However, due to the lack of specific markers, the precise phenotype and maturation status of these neutrophil populations remain unclear. Herein, we report that CD10, also known as common acute lymphoblastic leukemia antigen, neutral endopeptidase, or enkephalinase, can be used as a marker that, within heterogeneous populations of circulating CD66b+ neutrophils present in inflammatory conditions, clearly distinguishes the mature from the immature ones. Accordingly, we observed that the previously described immunosuppressive neutrophil population that appears in the circulation of granulocyte colony-stimulating factor (G-CSF)-treated donors (GDs) consists of mature CD66b+CD10+ neutrophils displaying an activated phenotype. These neutrophils inhibit proliferation and interferon γ (IFNγ) production by T cells via a CD18-mediated contact-dependent arginase 1 release. By contrast, we found that immature CD66b+CD10- neutrophils, also present in GDs, display an immature morphology, promote T-cell survival, and enhance proliferation and IFNγ production by T cells. Altogether, our findings uncover that in GDs, circulating mature and immature neutrophils, distinguished by their differential CD10 expression, exert opposite immunoregulatory properties. Therefore, CD10 might be used as a phenotypic marker discriminating mature neutrophils from immature neutrophil populations present in patients with acute or chronic inflammatory conditions, as well as facilitating their isolation, to better define their specific immunoregulatory properties.

The National Institutes of Health criteria for classification and scoring of chronic graft versus host disease: long-term follow-up of a single center series.

We assessed the retrospective applicability and prognostic value of the National Institutes of Health (NIH) classification of chronic graft versus host disease (cGVHD) in 159 consecutive patients after allogeneic hematopoietic stem cell transplant (HSCT). Seventy-four patients (46.5%) were affected by late-acute GVHD (n = 19; 25.7%), classic cGVHD (n = 44; 59.4%) and overlap syndrome (n = 11; 14.9%). Overall, patients with NIH-defined cGVHD (i.e. classic cGVHD and overlap syndrome) had better 10-year overall survival (OS) as compared to patients without GVHD (76.9% vs. 47.4%, p = 0.0002) or with late-acute GVHD (47.4%, p = 0.001). Relapse mortality (RM) was lower in patients with NIH-defined cGVHD than in patients without GVHD (14.5% vs. 38.7%, p = 0.001), but comparable to that of late-acute type (19.4%, p = 0.31). Non-relapse mortality (NRM) was lower in patients with NIH-defined cGVHD as compared to late-acute GVHD (10.0% vs. 41.1%, p = 0.0005), as well as patients without GVHD (22.2%, p = 0.045). At multivariate analysis, NIH-defined cGVHD remained independently predictive for lower RM, but not for NRM. Thus, the new NIH classification identifies two subtypes of GVHD (late-acute and chronic) with different long-term outcomes and impact on RM and NRM.

Peripheral blood CD5-positive B lymphocytes (B-1a cells) after allogeneic stem cell transplantation for acute myeloid leukaemia in humans.

BACKGROUND: Only few data are available in literature regarding the reconstitution of B- 1a cells after allogeneic bone marrow transplantation performed for haematological malignancies. METHODS: In this study we used flow cytometry to assess the reconstitution of the peripheral blood B-1a cell compartment after allogeneic peripheral blood stem cell transplantation. Cytometric analyses were performed over time on 11 consecutive patients undergoing allogeneic peripheral blood stem cell transplantation for acute myeloid leukaemia in our Haematology Unit and the results were compared with available data regarding B- 1a cell reconstitution after allogeneic bone marrow stem cell transplantation. RESULTS: In spite of an earlier recovery of B-1a cells in the peripheral blood after allogeneic bone marrow transplantation, the reconstitution of this B-cell subset was similar, regardless of the source of stem cells employed. CONCLUSIONS: Further studies are necessary in order to clarify the origin of B-1a cells in humans in health and illness.