Martin Schwonzen

Chronic Lymphocytic Leukemia with an Interfollicular Architecture: Avoiding Diagnostic Confusion with Monocytoid B-cell Lymphoma

Certain low grade B-cell lymphoproliferative disorders can be mistaken for each other morphologically, particularly when there is partial lymph node involvement. We encountered two cases of chronic lymphocytic leukemia, in which the interfollicular growth pattern and the pale appearance of the neoplastic proliferation in the lymph nodes led to a misclassification as monocytoid B-cell lymphoma. The correct diagnosis was established, however, when the lymph node morphology was carefully reexamined, with the knowledge of the clinical history, peripheral blood findings, and bone marrow data. The immunophenotype of the neoplastic cells in the peripheral blood (CD5, CD23, weak fluorescence intensity of surface immunoglobulin and CD22) and the lymph node immunohistochemistry (weak L26 staining, strong MT1 positivity) confirmed the diagnosis of chronic lymphocytic leukemia. These two cases demonstrate the necessity of a systematic approach to lymph node morphology and the utility of a multiparameter approach in the diagnosis of lymphoproliferative disorders.

Phenotyping of acute myelomonocytic (AMMOL) and monocytic leukemia (AMOL): Association of T-cell-related antigens and skin-infiltration in AMOL

Leukemic blast cells in 25 cases of AMMOL (13 cases) and AMOL (12 cases) were positive for My7 (CD13) and My4 (CD14), while only 44% reacted with LeuM3 (another CD14 MoAb). T-cell-related antigens were detected in 44% of the cases (CD2, 24%; CD4, 12%; CD7 36%). The expression of LeuM3 and TcrAg on blast and monocytic cells was mutually exclusive, with three cases expressing neither LeuM3 nor TcrAg. All six patients with myeloperoxidase negative AMOL and the TcrAG+/LeuM3- phenotype had leukemic skin infiltrations.

Once-Daily Oral Levofloxacin Monotherapy versus Piperacillin/Tazobactam Three Times a Day: A Randomized Controlled Multicenter Trial in Patients with Febrile Neutropenia

A prospective, randomized, controlled multicenter trial was performed to evaluate the efficacy and safety of once-daily oral monotherapy with 500 mg levofloxacin in comparison with 4.5 g piperacillin/tazobactam 3 times a day in patients with low-risk febrile neutropenia. Low risk was defined by oral temperature≥38.5°C on one occasion or ≥38.0°C twice within 24 hours and granulocytopenia ≤500/μL for less than 10 days. The primary end point was defined as defervescence after 72 hours followed by at least 7 afebrile days. Secondary end points were overall response, time to defervescence, survival on day 30, and toxicity. Thirty-four episodes were included. Fever of unknown origin accounted for 26 (76.5%) of the episodes, microbiologically defined infection for 5 (14.7%) of the episodes, and clinically defined infection for 3 (8.8%) of the episodes. On an intent-to-treat basis, all episodes were evaluable for the primary end point. Levofloxacin and piperacillin/tazobactam were successful after 72 hours of treatment in 76.5% and 88.3% of the episodes. Overall response was achieved in 94.1% and 100% of the episodes, respectively. One inpatient in the oral treatment group died of septic shock without identification of a causative pathogen. A larger phase III trial is warranted to further evaluate the lack of inferiority of the oral monotherapy regimen versus standard intravenous therapy.

Expression of alpha-3/4-monofucosylated polylactosaminoglycan epitope, as defined by monoclonal antibody FW6, is a marker of the colorectal adenoma–carcinoma sequence

Background. The expression of a distinct alpha‐3/4‐monofucosylated polylactosaminoglycan epitope, which is detected by monoclonal antibody FW6, was investigated by comparative immunohistochemical analysis of colorectal tissue specimens exhibiting different grades of premalignant and malignant transformation. The presence of this peculiar epitope was compared with different Lewis type 2 blood group antigens.

Binding of monoclonal anti-interleukin 2 antibody to nucleoli in acute leukemia blast cells.

Neutralizing anti-IL-2, anti-IL-3, and anti-IL-6 monoclonal antibodies (MAbs) were used for the immunoenzymatic detection of the respective cytokines in blast cells of 38 patients with acute myeloid (AML) and lymphoid (ALL) leukemias by the APAAP-technique. In 20/24 AML-cases (83%) blast cells showed intranuclear staining with MAb anti-IL-2 (DMS-1). In 17 cases reaction was restricted to the nucleoli, in 4 cases additional cytoplasmic staining was observed. Only 2/13 (15%) of the ALL cases showed anti-IL-2 staining. In contrast to IL-2, neither IL-3, IL-6 nor IL-2R alpha-chains were detected in any of the acute leukemias tested. The anti-IL-2 staining of nucleoli in AML cells is distinct from the cytoplasmic staining which is observed in PHA-activated normal lymphocytes and in a minority of AML cells.