Evaluation of peroxidase activity by alpha-naphthol/pyronine staining compared with benzidine staining in 101 acute leukemia cases.

Cytochemical detection of myeloperoxidase (MPO) activity, a strong marker for myeloid differentiation, is usually performed by benzidine dihydrochloride staining, with the threshold at 3%. Several reports have demonstrated the potential toxicity of benzidine, and bans have been issued, under French law, prohibiting female technicians from being exposed to the aromatic hydrocarbon group, including benzidine. The aim of this study was to test an alpha-naphthol and pyronine-based substitute using a standardized kit (MYELOPEROXIDASE KIT, RAL [Réactifs RAL, Martillac, France]) to measure MPO activity in blast cells. This prospective, multicenter study made it possible to analyze 101 acute leukemia (AL) cases; it has also demonstrated both the 96% specificity and the 99% sensitivity of the method, with a threshold for positive staining of 3%, as well as good correlation (r = 0.95) between the staining method tested and the benzidine staining method. When using the alpha-naphthol/pyronine-based staining for MPO, the mean number of positive blast cells is statistically lower than that obtained using benzidine, but without incidence on AL classification. These results allow us to conclude that this method makes it possible to classify acute blood diseases by measuring MPO activity using reagents permitted by law, according to a standardized and reproducible protocol.

Primary plasma cell leukemia mimicking an adult T-cell leukemia-lymphoma: a case report.

BACKGROUND: Malignant plasma cells ofmultiple myeloma (MM), or plasma cell leukemia (PCL), may present highly variable morphologic aspects. Adult T-cell leukemia-lymphoma (ATLL) is a peripheral T-cell neoplasm composed of highly pleomorphic lymphoid cells. We report an unusual case ofprimary PCL with misleading cellular morphology and some clinical and biologic similarities simulating ATLL. CASE: A 40-year-old Caribbean man presented with asthenia, epistaxis and diffuse bone pain. Blood cell count showed anemia and thrombocytopenia and a hyperleukocytosis composed of deeply basophilic cells with a polylobulated nucleus resembling flower cells. An ATLL diagnosis was given at first, without ruling out the possibility of a PCL diagnosis. Hypercalcemia and lytic bone lesions were compatible with both diagnoses. Immunophenotyping was key to the diagnosis of primary PCL. CONCLUSION: Some clinical and biological overlap may exist between PCL and ATLL, leading to a false diagnosis or delaying a correct one. An accurate cytologic analysis leading to a rapid detection of plasma cell markers is essential for an early diagnosis.

Hematopoietic stem cell transplantation for de novo erythroleukemia: a study of the European Group for Blood and Marrow Transplantation (EBMT).

De novo erythroleukemia (EL) is a rare disease. Reported median survival are poor and vary from 4 to 14 months. The value of hematopoietic stem cell transplantation (HSCT) for EL is unknown. This EBMT registry study reports on the largest series of patients with EL treated with HSCT in first complete remission-103 autologous and 104 HLA identical sibling allogeneic HSCT. Outcome and identification of prognostic factors for each type of transplantation were evaluated. For autologous HSCT, outcome at 5 years showed a leukemia-free survival (LFS) of 26% +/- 5%, a relapse incidence (RI) of 70% +/- 6%, and a transplant-related mortality (TRM) of 13% +/- 4%. By multivariate analysis, the only prognostic factor was age. For allogeneic HSCT, outcome at 5 years showed an LFS of 57% +/- 5%, an RI of 21% +/- 5%, and a TRM of 27% +/- 5%. By multivariate analysis, prognostic factors were graft-versus-host disease and age. This study represents the largest series of de novo EL treated with HSCT and shows that allogeneic HSCT is by far the most effective treatment.