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Tγδ large granular lymphocyte leukemia (LGLL) is a rare variant of T-cell LGLL (T-LGLL) that has been less investigated as compared with the more frequent Tαβ LGLL, particularly in terms of frequency of STAT3and STAT5bmutations. In this study, we characterized the clinical and biological features of 137 patients affected by Tγδ LGLL; data were retrospectively collected from 1997 to 2020 at 8 referral centers. Neutropenia and anemia were the most relevant clinical features, being present in 54.2% and 49.6% of cases, respectively, including severe neutropenia and anemia in ∼20% of cases each. Among the various treatments, cyclosporine A was shown to provide the best response rates. DNA samples of 97 and 94 cases were available for STAT3and STAT5bmutations analysis, with 38.1% and 4.2% of cases being mutated, respectively. Clinical and biological features of our series of Tγδ cases were also compared with a recently published Tαβ cohort including 129 cases. Though no differences in STAT3and STAT5bmutational frequency were found, Tγδ cases more frequently presented with neutropenia (P = .0161), anemia (P < .0001), severe anemia (P = .0065), and thrombocytopenia (P = .0187). Moreover, Vδ2−cases displayed higher frequency of symptomatic disease. Overall, Tγδ cases displayed reduced survival with respect to Tαβ cases (P = .0017). Although there was no difference in STAT3mutation frequency, our results showed that Tγδ LGLL represents a subset of T-LGLL characterized by more frequent symptoms and reduced survival as compared with Tαβ LGLL.

In recent years, multiparameter flow cytometry MFC immunophenotyping has become mandatory in the clinical management of hematological malignancies, both for diagnostic and monitoring purposes. Multiple myeloma MM and other clonal plasma cellrelated PC disorders should be no exception to this paradigm, but incorporation of immunophenotypic studies in the management of patients with PC disorders is still far from being routinely established in many diagnostic flow cytometry laboratories. For clonal PC disorders, MFC is of clear and established clinical relevance in: 1 the differential diagnosis between MM and other PCrelated disorders; 2 the identification of highrisk MGUS and smoldering MM; 3 minimal residual disease investigation after therapy; additionally it may also be useful for 4 the definition of prognosisassociated antigenic profiles; and 5 the identification of new therapeutic targets. In this article, we review the clinical value of MFC in the study of PC disorders, with specific emphasis in those areas where consensus exists on the need to incorporate MFC into routine evaluation of MM and other clonal PCrelated disorders. © 2010 Clinical Cytometry Society

Background:Monoclonal Bcell lymphocytosis MBL indicates <5 × 109peripheral blood PB clonal BcellsL in healthy individuals. In most cases, MBL cells show similar phenotypicgenetic features to chronic lymphocytic leukemia cells—CLLlike MBL—but little is known about nonCLLlike MBL.Methods:PB samples from 639 healthy individuals 46 men54 women >40 years old 62 ± 13years with normal lymphocyte counts 2.1 ± 0.7 × 109L were immunophenotyped using highsensitive flow cytometry, based on 8color stainings and the screening for >5 × 106total PB leukocytes.Results:Thirteen subjects 2.0; 9 males4 females, aged 73 ± 10 years; absolute lymphocyte count: 2.4 ± 0.8 × 109L showed a nonCLLlike clonal Bcell population, whose frequency clearly increased with age: 0.4, 3, and 5.4 of subjects aged 40–59, 60–79, and ≥80 years, respectively. One single Bcell clone was detected in 913 cases, while two Bcell clones were found in 413 n 17 MBL populations. Nine MBL cell populations showed a CD5−phenotype usually overlapping with marginal zonederived MZL or lymphoplasmacytic LPL nonHodgkin lymphoma NHL Bcells, or an unclassifiable NHL, but CD5−dn 3 and CD5n 3 nonCLLlike MBL, consistent with a mantlecell lymphoma MCLlike phenotype, and n 2 CLLlike MBL were also identified; iFISH supported the diagnosis in most cases. No preferential IGHV usage of Bcell receptor could be found. Twelve cases reevaluated at month 12 showed circulating clonal Bcells, at mean levels significantly higher than those initially detected.Conclusions:NonCLLlike MBL cases frequently show biclonality, in association with MZL, LPL, MCLlike, or unclassifiable phenotypic profiles. As with CLLlike MBL, the frequency of nonCLLlike MBL increases with age, with a clear predominance of males. © 2010 International Clinical Cytometry Society

Staining for intracellular markers with the Fix & Perm™ reagent is associated with variations in the scatter properties of leucocytes, limiting automated analysis of flow cytometry FCM data. Here, we investigated those variables significantly contributing to changes in the light scatter, autofluorescence, and bcl2 staining characteristics of peripheral blood PB leucocytes, after fixation with Fix & PermTM. Our major aim was to evaluate a new mathematical approach for automated harmonization of FCM data from datafiles corresponding to aliquots of a sample treated with cellsurfaceonly versus Fix & Perm intracellular staining techniques. Overall, neither the anticoagulant used nor sample storage for <24 h showed significant impact on the light scatter and fluorescence properties of PB leucocytes; similarly, the duration of the fixation period once >15 min were used had a minimum impact on the FCM properties of PB leucocytes. Conversely, changes in cellprotein concentrations and the fixativesample volvol ratio had a clear impact on the light scatter features of some populations of leucocytes. Accordingly, lower cellprotein concentrations were associated with lower scatter values, particularly for the neutrophils. Such changes could be partially corrected through the use of higher fixative to sample volume ratios. Despite the variable changes detected between aliquots of the same sample treated with cell surfaceonly versus intracellular staining procedures, the new mathematical approach here proposed and evaluated for automated harmonization of common parameters in both datafiles, could correct the FCM profiles of leucocytes derived from cells undergoing conventional fixationpermeabilization procedures, and made them indistinguishable from those corresponding to aliquots of the same sample treated with cellsurfaceonly staining techniques. © 2009 Clinical Cytometry Society

Las secuelas cardiacas tras la infección por SARS-CoV-2 todavía están poco documentadas. Se realizó un estudio transversal en trabajadores sanitarios para estudiar la prevalencia de afección pericárdica y miocárdica tras la infección por SARS-CoV-2.

Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal T-cell receptor (TCR)–αβ+/CD4+/NKa+/CD8−/+dimT-large granular lymphocyte (LGL) lymphocytosis. Because healthy persons show (oligo)clonal expansions of human cytomegalovirus (hCMV)–specific TCRVβ+/CD4+/cytotoxic/memory T cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4+T-LGL. Peripheral blood samples from patients with monoclonal TCR-αβ+/CD4+T-LGL lymphocytosis and other T-chronic lymphoproliferative disorders were evaluated for the specific functional response against hCMV and hEBV whole lysates as well as the “MQLIPDDYSNTHSTRYVTVK” hCMV peptide, which is specifically loaded in HLA-DRB1*0701 molecules. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile analysis. Patients with TCR-αβ+/CD4+T-LGL displayed a strong and characteristic hCMV-specific functional response, reproduced by the hCMV peptide in a subset of HLA-DRB1*0701+patients bearing TCRVβ13.1+clonal T cells. Gene expression profile showed that the hCMV-induced response affects genes involved in inflammatory and immune responses, cell cycle progression, resistance to apoptosis, and genetic instability. This is the first study providing evidence for the involvement of hCMV in the ontogeny of CD4+T-LGL, emerging as a model disorder to determine the potential implications of quite a focused CD4+/cytotoxic immune response.

Immunophenotypic characterization of Bcell chronic lymphoproliferative disorders BCLPD is associated with the use of increasingly larger panels of multiple combinations of 3 to ≥6 monoclonal antibodies Mab, data analysis being separately performed for each of the different stained sample aliquots. Here, we describe and validate an automated method for calculation of flow cytometric data from several multicolor stainings of the same cell sample—i.e., the merging of data from different aliquots stained with partially overlapping combinations of Mab reagents focusing on ≥1 cell populations—into one data file as if it concerned a single “super” multicolor staining. Evaluation of the performance of the method described was done in a group of 60 BCLPD studied at diagnosis with 18 different reagents in a panel containing six different 3 and 4color stainings, which systematically contained CD19 for the identification of Bcells. Our results show a high degree of correlation and agreement between originally measured and calculated data about cell surface stainings, providing a basis for the use of this approach for the generation of flow cytometric data files containing information about a virtually infinite number of stainings for each individual cellular event measured in a sample, using a limited number of fluorochrome stainings. © 2008 International Society for Advancement of Cytometry

Monoclonal TCRαβ+/CD4+T-large granular lymphocyte (T-LGL) lymphocytosis is a T-cell disorder with a restricted TCR-Vβ repertoire. In the present study we explored the potential association between the expanded TCR-Vβ families, the CDR3 sequences of the TCR-Vβ gene, and the HLA genotype of patients with monoclonal TCRαβ+/CD4+T-LGL lymphocytosis. For that purpose, 36 patients with monoclonal TCRαβ+/CD4+T-LGL lymphocytosis (15 TCR-Vβ13.1 versus 21 non–TCR-Vβ13.1) were selected. For each patient, both the HLA (class I and II) genotype and the DNA sequences of the VDJ-rearranged TCR-Vβ were analyzed. Our results show a clear association between the TCR-Vβ repertoire and the HLA genotype, all TCR-Vβ13.1+cases being HLA-DRB1*0701 (P= .004). Interestingly, the HLA-DR7/TCR-Vβ13.1–restricted T-cell expansions displayed a highly homogeneous and strikingly similar TCR arising from the use of common TCR-Vβ gene segments, which shared (1) unique CDR3 structural features with a constantly short length, (2) similar combinatorial gene rearrangements with frequent usage of the Jβ1.1 gene, and (3) a homolog consensus protein sequence at recombination junctions. Overall, these findings strongly support the existence of a common antigen-driven origin for monoclonal CD4+T-LGL lymphocytosis, with the identification of the exact peptides presented to the expanded T cells deserving further investigations.

HIV‐1 infection has been associated with high expression of CD38 on peripheral blood (PB) CD8+ and CD4+ T‐cells, which has been related with poor prognosis in untreated HIV‐1+ patients. In turn, CD38 expression on PB monocytes from HIV‐1+ individuals and its behavior after starting antiretroviral therapy (ART) have been poorly studied.CD38 expression on PB CD8+ and CD4+ T‐lymphocytes and monocytes was prospectively analyzed in 30 ART‐naive HIV‐1+ patients, using a quantitative multiparameter flow cytometry approach. Patients were tested prior to therapy, and at weeks +2, +4, +8, +12, and +52 after ART.Prior to ART, CD38 expression was significantly increased on PB CD8+ and CD4+ T‐cells and monocytes; despite a significant decrease after ART, CD38 expression remained abnormally high on PB CD8+ T‐cells and monocytes, even after one year of therapy, in the absence of detectable plasma viral load. The ART‐induced early changes on CD38 expression by PB T‐cells and monocytes differed among the cell subsets analyzed and patient groups, probably reflecting an interaction between the direct effects of therapy and a redistribution of the PB compartments of T‐cells and monocytes. Hierarchical clustering analysis showed that the overall pattern of changes in CD38 expression observed early after starting ART was predictive of a better response to therapy, not only for PB CD8+ T‐cells, but also for CD4+ T‐cells and monocytes. Accordingly, those HIV‐1+ patients, who experienced a more pronounced increase in CD38 expression on both PB CD4+ T‐cells and monocytes after 2 weeks of ART, showed a more rapid viral clearance, which might reflect decreased HIV‐1 replication in lymph nodes and other tissues, and a partial restoration of hematopoiesis.Combined quantitative measurement of CD38 expression on PB monocytes, and CD8+ and CD4+ T‐cells is a more useful tool for monitoring HIV‐1+ patients under ART, rather than quantitation of CD38 expression on PB CD8+ T‐lymphocytes alone. © 2006 International Society for Analytical Cytology

Glycosylphosphatidylinositol‐anchored proteins (GPI‐AP) are a heterogeneous group of proteins deficiently expressed in patients with paroxysmal nocturnal hemoglobinuria. Up till now, no study has been reported in which the exact patterns of expression of a large number of GPI‐AP are quantitatively evaluated in normal bone marrow (BM) cells classified according to their lineage and maturation stage.In the present study, we have quantitatively analyzed the expression of eleven different GPI‐AP (CD14, CD16, CD24, CD48, CD52, CD58, CD59, CD66b, CD87, CD109 and CD157) during maturation of the neutrophil, monocytic, erythroid, lymphoid, basophil and plasmacytoid dendritic cells (DC) lineages in normal BM as a frame of reference for the understanding of the abnormal patterns of expression of GPI‐AP observed in the BM of PNH patients.Our results show that expression of most GPI‐AP varies during normal BM maturation, different profiles being frequently observed depending on the cell lineage or the GPI‐AP analyzed.Overall, these results provide a detailed map GPI‐AP expression during normal hematopoietic differentiation, which could serve as a basis for the identification and characterization of changes occurring in PNH. © 2006 International Society for Analytical Cytology

Despite the relevance of the c-kit/stem cell factor (SCF) signaling pathway in mast cell (MC) diseases, the exact frequency of KITmutations in different compartments of bone marrow (BM) hematopoietic cells of individuals with systemic mastocytosis (SM), and its different diagnostic categories, remains unknown. In this study, we prospectively analyzed the presence of KITmutations in fluorescence-activated cell-sorting (FACS)– purified populations of BM MCs (n = 113) and other BM cell compartments (n = 67) from adults with SM. Our results show the presence of D816V KITmutation in virtually all adults (93%) with indolent and aggressive forms of SM, except well-differentiated SM (29%), while other KITmutations were rarely (< 3%) detected. In around one-third of patients with mutated MCs, the KITmutation was also detected in CD34+hematopoietic cells and eosinophils, and, to a lesser extent, in monocytic, neutrophil-lineage BM precursor cells and lymphocytes. Most patient with poor-prognosis SM (81%) carried the KITmutation in 2 or more BM myeloid cell populations, while this was detected in a smaller proportion (27%) of indolent cases. These results would support the notion that KITmutation is a hallmark of adult SM where it targets a pluripotent hematopoietic stem cell, and may contribute to explaining previously observed discrepancies in the literature.

Despite the relevance of the c-kit/stem cell factor (SCF) signaling pathway in mast cell (MC) diseases, the exact frequency of KIT mutations in different compartments of bone marrow (BM) hematopoietic cells of individuals with systemic mastocytosis (SM), and its different diagnostic categories, remains unknown. In this study, we prospectively analyzed the presence of KIT mutations in fluorescence-activated cell-sorting (FACS)– purified populations of BM MCs (n = 113) and other BM cell compartments (n = 67) from adults with SM. Our results show the presence of D816V KIT mutation in virtually all adults (93%) with indolent and aggressive forms of SM, except well-differentiated SM (29%), while other KIT mutations were rarely (< 3%) detected. In around one-third of patients with mutated MCs, the KIT mutation was also detected in CD34+ hematopoietic cells and eosinophils, and, to a lesser extent, in monocytic, neutrophil-lineage BM precursor cells and lymphocytes. Most patient with poor-prognosis SM (81%) carried the KIT mutation in 2 or more BM myeloid cell populations, while this was detected in a smaller proportion (27%) of indolent cases. These results would support the notion that KIT mutation is a hallmark of adult SM where it targets a pluripotent hematopoietic stem cell, and may contribute to explaining previously observed discrepancies in the literature.

Indolent natural killer (NK) cell lymphoproliferative disorders include a heterogeneous group of patients in whom persistent expansions of mature, typically CD56+, NK cells in the absence of any clonal marker are present in the peripheral blood. In the present study we report on the clinical, hematological, immunophenotypic, serological, and molecular features of a series of 26 patients with chronic large granular NK cell lymphocytosis, whose NK cells were either CD56−or expressed very low levels of CD56 (CD56−/+dimNK cells), in the context of an aberrant activation-related mature phenotype and proved to be monoclonal using the human androgen receptor gene polymerase chain reaction-based assay. As normal CD56+NK cells, CD56−/+dimNK cells were granzyme B+, CD3−, TCRαβ/γδ−, CD5−, CD28−, CD11a+bright, CD45RA+bright, CD122+, and CD25−and they showed variable and heterogeneous expression of both CD8 and CD57. Nevertheless, they displayed several unusual immunophenotypic features. Accordingly, besides being CD56−/+dim, they were CD11b−/+dim(heterogeneous), CD7−/+dim(heterogeneous), CD2+(homogeneous), CD11c+bright(homogeneous), and CD38−/+dim(heterogeneous). Moreover, CD56−/+dimNK cells heterogeneously expressed HLA-DR. In that concerning the expression of killer receptors, CD56−/+dimNK cells showed bright and homogeneous CD94 expression, and dim and heterogeneous reactivity for CD161, whereas CD158a and NKB1 expression was variable. From the functional point of view, CD56−/+dimshowed a typical Th1 pattern of cytokine production (interferon-γ+, tumor necrosis factor-α+). From the clinical point of view, these patients usually had an indolent clinical course, progression into a massive lymphocytosis with lung infiltration leading to death being observed in only one case. Despite this, they frequently had associated cytopenias as well as neoplastic diseases and/or viral infections. In summary, we describe a unique and homogeneous group of monoclonal chronic large granular NK cell lymphocytosis with an aberrant activation-related CD56−/+dim/CD11b−/+dimphenotype and an indolent clinical course, whose main clinical features are related to concomitant diseases.

Mastocytosis is a term used for a heterogeneous group of disorders characterized by an abnormal proliferation and accumulation of mast cells (MCs) in one or multiple tissues including skin, bone marrow, liver, spleen, and lymph nodes, among others. In recent years, multiparameter flow cytometric studies have shown that pathologic MCs from patients with mastocytosis display unique aberrant immunophenotypic characteristics as compared with normal MCs. Among other features, pathologic MCs show aberrant expression of CD25 and CD2 antigens and abnormally high levels of the CD11c and CD35 complement receptors, the CD59 complement regulatory molecule, the CD63 lysosomal membrane antigen, and the CD69 early-activation antigen. In addition, MCs from mastocytosis express abnormally low levels of CD117 and unexpectedly high light scatter and autofluorescence characteristics. These aberrant immunophenotypic features are of great relevance for the assessment of tissue involvement in mastocytosis with consequences in the diagnosis, classification, and follow-up of the disease and in its differential diagnosis with other entities. In this paper we provide the reader with information for the objective and reproducible identification of pathologic MCs by using quantitative multiparametric flow cytometry, information for their phenotypic characterization, and the criteria currently used for a correct interpretation of the immunophenotypic results obtained. © 2004 Wiley-Liss, Inc.

Large granular lymphocyte (LGL) leukemia is a well-recognized disease of mature T-CD8+or less frequently natural killer cells; in contrast, monoclonal expansions of CD4+T-LGL have only been sporadically reported in the literature. In the present article we have explored throughout a period of 56 months the incidence of monoclonal expansions of CD4+T-LGL in a population of 2.2 million inhabitants and analyzed the immunophenotype and the pattern of cytokine production of clonal CD4+T cells of a series of 34 consecutive cases. Like CD8+T-LGL leukemias, CD4+T-LGL leukemia patients have an indolent disease; however, in contrast to CD8+T-LGL leukemias, they do not show cytopenias and autoimmune phenomena and they frequently have associated neoplasias, which is usually determining the clinical course of the disease. Monoclonal CD4+T-LGLshowed expression of TCRαβ, variable levels of CD8 (CD8−/+dim) and a homogeneous typical cytotoxic (granzyme B+, CD56+, CD57+, CD11b+/−) and activated/memory T cell (CD2+bright, CD7−/+dim, CD11a+bright, CD28−, CD62L−HLA-DR+) immunophenotype. In addition, they exhibited a Th1 pattern of cytokine production [interferon-γ++, tumor necrosis factor-α++, interleukin (IL-2)−/+, IL-4−, IL-10−, IL-13−]. Phenotypic analysis of the TCR-Vβ repertoire revealed large monoclonal TCR-Vβ expansions; only a restricted number of TCR-Vβ families were represented in the 34 cases analyzed. These findings suggest that monoclonal TCRαβ+/CD4+/NKa+/CD8−/+dimT-LGL represent a subgroup of monoclonal LGL lymphoproliferative disorders different from both CD8+T-LGL and natural killer cell-type LGL leukemias. Longer follow-up periods are necessary to determine the exact significance of this clonal disorder.

At present, a major challenge in the initial diagnosis of leukemia of large granular lymphocytes (LGLs) is to establish the clonal nature of the expanded population. In the present study we have analyzed by flow cytometry immunophenotyping the TCR-Vβ repertoire of 98 consecutive cases of persistent expansions of CD4+or CD8+brightCD3+/TCR-αβ+LGLs and compared the results with those obtained in molecular studies of TCR-β gene rearrangements. Fifty-eight cases were considered to be monoclonal in molecular studies whereas in the remaining 40 cases there was no evidence for monoclonality (11 cases were considered oligoclonal and 29 polyclonal). The TCR-Vβ repertoire was biased to the preferential use of one or more TCR-Vβ families in 96% of cases, a total of 124 TCR-Vβ expansions being diagnosed: one TCR-Vβ expansion in 71 cases and two or more TCR-Vβ expansions in 23 cases. The highest TCR-Vβ expansion observed in each case was higher among monoclonal (74 ± 19%) as compared to nonmonoclonal cases (24 ± 14%) (P= 0.001), as did the fraction of LGLs that exhibited a TCR-Vβ-restricted pattern (86 ± 16% and 42 ± 23%, respectively;P= 0.0001); by contrast, the proportion of cases displaying more than one TCR-Vβ expansion was higher in the latter group: 7%versus48%, respectively (P= 0.001). Results obtained in oligoclonal cases were intermediate between those obtained in polyclonal and monoclonal cases and similar results were observed for CD4+as for CD8+brightT-cell expansions. TCR-Vβ familiesexpressed in CD8+brightT-cell-LGL proliferations showed a pattern of distribution that mimics the frequency at which the individual TCR-Vβ families are represented in normal peripheral blood T cells. Assuming that a given proliferation of LGLs is monoclonal whenever there is an expansion of a given TCR-Vβ family of at least 40% of the total CD4+or CD8+brightT-cell compartment, we were able to predict clonality with a sensitivity of 93% and a specificity of 80%. By increasing the cut-off value to 60%, sensitivity and specificity were of 81% and 100%. In summary, our results suggest that flow cytometry immunophenotypic analysis of the TCR-Vβ repertoire is a powerful screening tool for the assessment of T-cell clonality in persistent expansions of TCR-αβ+LGLs.

Human peripheral blood (PB) CD14lo/HLA-DR+cells were initially described as a subset of mature monocytes. Recently, it has been suggested that these represent a part of a new subset of dendritic cells (DC), characterized by the coexpression of MDC-8/HLA-DR/CD16. The aim of the present paper was to analyze the morphological, cytochemical, phenotypical, and functional characteristics of PB CD16+/HLA-DR+cells compared to both PB CD14+monocytes and CD16−DC. In contrast to CD14+monocytes, purified CD16+/HLA-DR+cells displayed cytoplasmic veils and lacked cytoplasmic myeloperoxidase and α-naphthyl acetate esterase. Normal human PB CD16+/HLA-DR+cells also displayed phenotypic characteristics different from those of CD14+monocytes: they lacked the CD64 Fcγ receptor, showed lower levels of CD32, and expressed higher amounts of CD16 compared to CD14+monocytes. They also displayed a different pattern of expression of other antigens, including CD14, HLA-DR, CD45RA, CD45RO, complement receptors and complement regulatory surface proteins, adhesion and costimulatory molecules, and cytokine receptors, among others. When compared to CD16−DC, CD16+/HLA-DR+cells showed reactivity for CD16, dim positivity for CD14, higher expression of both Ig- and complement-receptors and lower reactivity for HLA-DR, adhesion, and costimulatory molecules (with the exception of CD86). The CD16+/HLA-DR+cell subset displayed a higher Ig/complement-mediated phagocytic/oxidative activity than CD16−DC, although this activity was significantly lower than that of mature monocytes. Regarding cytokine production at the single cell level, LPS plus IFN-γ-stimulated PB CD16+/HLA-DR+cells produced significant amounts of IL1β, IL6, IL12, TNFα, and IL8; however, the percentage of cytokine-producing cells and the amount of cytokine/cell were lower in CD16+/HLA-DR+cells than in CD14+monocytes. In addition, upon comparing CD16+/HLA-DR+cells with CD33+++/CD16−DC, we found that the percentage of cytokine-producing cells and the amount of cytokine/cell were significantly different in both cell subsets. In summary, our results show that CD16+/HLA-DR+cells clearly display different morphologic, cytochemical, immunophenotypical, and functional characteristics compared to both mature monocytes and CD16−DC. Interestingly, these cells are more frequent than other DC in normal human adult PB and cord blood samples, while they are less represented in normal bone marrow.