title: Incidence and characteristics of CD4(+)/HLA DRhi dendritic cell malignancies.
abstract: OBJECTIVE
  Recent reports suggest that CD4(+)/CD56(+)/lineage(-) hematopoietic neoplasias are aggressive types of malignancies involving lymphoplasmacytoid/DC2 dendritic cells (DC). Here, we report on the incidence of DC malignancies and their clinical, biological, phenotypic and cytogenetic characteristics.
  
  
  METHODS
  From a large series of 392 patients with acute myeloblastic leukemia (AML) and 739 with non-Hodgkin's lymphoma (NHL), five cases (three presenting as acute leukemia and two as NHL) showed clinical, morphologic and phenotypic features compatible with a DC malignancy.
  
  
  RESULTS
  The overall incidence of DC malignancies among all AML and NHL cases was 0.76% and 0.27%, respectively. At presentation, these patients displayed cutaneous nodules, splenomegaly and lymph node involvement with variable levels of peripheral blood (PB) and/or bone marrow (BM) infiltration in association with anemia and thrombocytopenia. Cytologic studies showed immature appearing blast cells with negative cytochemistry reactions for both myeloperoxidase and esterases. A highly suggestive DC phenotype based on co-expression of CD123(hi)/HLADR(+)/lin(-)/CD56(+)/CD45(dim) associated with a germline configuration of both the IgH and TCRgamma genes was found in all except one patient who was CD56(-). Expression of other markers compatible with a DC origin was found in all cases.
  
  
  CONCLUSIONS
  We show that DC-derived malignancies can present as either cutaneous lymphoma or acute leukemia, although their incidence is extremely low (<< >1%). While most of these DC neoplasias probably correspond to the malignant counterpart of DC2/lymphoplasmacytoid DC, neoplasias of myeloid DC might also exist, chemotherapy followed by consolidation with ASCT is apparently the most effective strategy for achieving a durable remission in these individuals.
authors.affiliation: Servicios de Citometria y Hematologia, Hospital Universitario de Salamanca, Centro de Investigacio' del Cancer, Universidad de Salamanca, Salamanca, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Bueno
authors.forename: Julia
authors.initials: J
authors.lastname: Almeida
authors.forename: Paulo
authors.initials: P
authors.lastname: Lucio
authors.forename: Josefa
authors.initials: J
authors.lastname: Marco
authors.forename: Raimundo
authors.initials: R
authors.lastname: Garcia
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: de Pablos
authors.forename: Antonio
authors.initials: A
authors.lastname: Parreira
authors.forename: Fernando
authors.initials: F
authors.lastname: Ramos
authors.forename: Francisco
authors.initials: F
authors.lastname: Ruiz-Cabello
authors.forename: Dimas
authors.initials: D
authors.lastname: Suarez-Vilela
authors.forename: Jesus F
authors.initials: JF
authors.lastname: San Miguel
authors.forename: Alberto
authors.initials: A
authors.lastname: Orfao
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D015704:CD4 Antigens / Q000096:biosynthesis* / Q000276:immunology; D003713:Dendritic Cells / Q000737:chemistry* / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006684:HLA-DR Antigens / Q000096:biosynthesis* / Q000276:immunology; D006801:Humans; D016130:Immunophenotyping; D015994:Incidence; D007938:Leukemia / Q000453:epidemiology; D015470:Leukemia, Myeloid, Acute / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology / Q000379:methods*; D010641:Phenotype; D016896:Treatment Outcome
chemical_list: D015704:CD4 Antigens; D006684:HLA-DR Antigens