CD71 is selectively and ubiquitously expressed at high levels in erythroid precursors of all maturation stages: a comparative immunochemical study with glycophorin A and hemoglobin A.

Histology assessment of erythroid precursors in bone marrow biopsies can be challenging under pathologic conditions and often requires ancillary studies. CD71 (transferring receptor-1) is known to be expressed in the earliest erythroid precursors, and has been useful for flow cytometry. However, CD71 is also regarded as a proliferation marker, and its lineage specificity has not been systemically investigated by immunohistochemistry in detail.

Flow cytometry rapidly identifies all acute promyelocytic leukemias with high specificity independent of underlying cytogenetic abnormalities.

Acute promyelocytic leukemia (APL) is a highly aggressive disease requiring prompt diagnosis and specific early intervention. Immunophenotyping by flow cytometry (FCM) facilitates a rapid diagnosis, but commonly used criteria are neither sufficiently sensitive nor specific. With an antibody panel for diagnostic screening in routine practice, we found all 149 APL cases in this study exhibited a unique immunophenotypic profile, ie, a characteristic CD11b- myeloid population and absent CD11c expression in all myeloid populations; 96.

Immunophenotypic analysis of CD103+ B-lymphoproliferative disorders: hairy cell leukemia and its mimics.

CD103 is characteristically expressed in hairy cell leukemia (HCL), a B-lymphoproliferative disorder highly responsive to treatment with purine analogs. Other CD103+ diseases are rare and do not respond well to the same therapy, including HCL variant (HCLv) and splenic marginal zone B-cell lymphoma (SMZL) variants. We analyzed 215 cases of CD103+ B-lymphoproliferative disorders to further delineate their immunophenotypic features.

Detection of phospho-STAT5 in mast cells: a reliable phenotypic marker of systemic mast cell disease that reflects constitutive tyrosine kinase activation.

Systemic mastocytosis (SM) is characterized by the abnormal proliferation and accumulation of mast cells (MCs). Constitutive activation of kit, a receptor tyrosine kinase (TK), has been associated with all types of SM. Signal transducers and activators of transcription (STATs), such as STAT5, mediate downstream kit signalling.

Detection of the t(11;18) API2/MALT1 translocation associated with gastric MALT lymphoma in routine formalin-fixed, paraffin-embedded small endoscopic biopsy specimens by robust real-time RT-PCR.

The t(11;18)(q21;q21) API2/MALT1 translocation is a specific chromosomal abnormality in extranodal marginal B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) type, particularly in those occurring in the stomach and lungs. Identification of t(11;18) may aid in the diagnosis of MALT lymphoma and strongly predicts resistance of gastric MALT lymphoma to Helicobacter pylori eradication therapy. We developed a robust real-time reverse transcription-polymerase chain reaction (RT-PCR) procedure to efficiently detect t(11;18) in virtually all types of specimens used in routine diagnostic workups.

Heterogeneous CD52 expression among hematologic neoplasms: implications for the use of alemtuzumab (CAMPATH-1H).

Purpose: CD52 is a GPI-linked glycoprotein expressed by B cells, T cells, monocytes, and macrophages. The humanized monoclonal antibody alemtuzumab (CAMPATH-1H) is specific for CD52 and is Food and Drug Administration - approved for the treatment of relapsed or refractory chronic lymphocytic leukemia (CLL). The utility of CAMPATH in the treatment of other hematologic neoplasms has been explored; however, a comprehensive survey of CD52 expression among a broad spectrum of WHO-defined tumor types has not been completed.

Expression of the B cell-associated transcription factors PAX5, OCT-2, and BOB.1 in acute myeloid leukemia: associations with B-cell antigen expression and myelomonocytic maturation.

The aberrant expression of the B-cell transcription factor PAX5 has been described in a subset of acute myeloid leukemia (AML) with t(8;21)(q22;q22) in association with B-cell antigen expression. However, the expression of other B cell-associated transcription factors, particularly OCT-2 and its B cell-specific coactivator BOB.1, has not been described in AML.

Plasmablastic lymphoma in HIV-positive patients: an aggressive Epstein-Barr virus-associated extramedullary plasmacytic neoplasm.

AIDS-associated aggressive B-cell lymphomas often have plasmacytoid features. Plasma cell neoplasms in HIV patients were commonly described to have atypical morphology and an aggressive clinical course in the literature. We reviewed 14 cases of neoplasms with marked plasmacytic differentiation in HIV-positive patients to determine their clinicopathologic features.

B-cell specific activation protein encoded by the PAX-5 gene is commonly expressed in merkel cell carcinoma and small cell carcinomas.

PAX-5 is a B cell specific transcription factor crucial for B cell ontogeny and has been detected in most of human B-cell lymphomas. In mouse, PAX-5 is also highly expressed in the central nervous system under tight temporal and spatial controls during embryogenesis. In humans, however, detection of PAX-5 in cells other than B lymphocytes has rarely been reported.

CD148 and CD27 are expressed in B cell lymphomas derived from both memory and naïve B cells.

CD148 and CD27 are activation antigens involved in B cell and T cell activation and development. They have been recently proposed as markers of normal human memory B cells corresponding to the presence of somatically hypermutated IgV genes. We undertook an immunohistochemical study of CD148 and CD27 expression on neoplastic B cells in 116 cases of B cell non-Hodgkin's lymphoma.

B-cell lymphomas with coexpression of CD5 and CD10.

Coexpression of CD5 and CD10 is highly unusual in B-cell lymphomas and may pose a diagnostic challenge. We report 42 cases of B-cell lymphoma with simultaneous expression of CD5 and CD10. They made up approximately 0.

CD30-positive T-cell lymphomas co-expressing CD15: an immunohistochemical analysis.

The characteristic histologic features and immunophenotype are usually diagnostic and allow distinguishing CD30 positive T-cell lymphoma (including anaplastic large cell lymphoma) from classical Hodgkin's lymphoma. The latter differs by expression of CD15 and lack of CD45, pan-T antigens and ALK expression. We report nine cases of large cell hematopoietic neoplasms in which the neoplastic cells co-expressed CD30 and CD15, and had immunophenotypic and morphologic features of T-cell lymphoproliferative process.

KSHV- and EBV-associated germinotropic lymphoproliferative disorder.

Kaposi sarcoma-associated herpesvirus (KSHV) is known to be associated with 3 distinct lymphoproliferative disorders: primary effusion lymphoma (PEL), multicentric Castleman disease (MCD), and MCD-associated plasmablastic lymphoma. We report 3 cases of a previously undescribed KSHV-associated lymphoproliferative disorder. The disease presented as localized lymphadenopathy and showed a favorable response to chemotherapy or radiotherapy.

CD5- mantle cell lymphoma.

Mantle cell lymphoma (MCL) typically expresses B-cell antigens and CD5 and overexpresses bcl-1 protein. However, unusual cases of bcl-1+ and CD5-MCL have been observed, posing a practical challenge for correct diagnosis and management. We identified 25 cases (48 samples) of bcl-1+ and CD5- lymphoma.