Essential thrombocythemia (ET) is a chronic myeloproliferative disorder that can rarely undergo leukemic transformation either in treated (3-7%) or untreated patients (1%). Evolution to myeloblastic or myelomonoblastic acute leukemia is commonly described in the literature, whereas lymphatic and megakaryocytic forms are considered unusual. Here, we report three cases of acute megakaryocytic leukemia (LMA-M7) among 11 acute leukemic transformations observed in our series of 321 ET patients. LMA-M7 was diagnosed employing immunophenotyping according to FAB criteria. These recurrences of LMA M7 suggest that this kind of evolution cannot be considered rare or casual in ET.

Background. The debate continues as to whether Richter syndrome should be defined as non‐Hodgkin lymphoma (NHL) because of a more malignant clone of neoplastic cells superimposed on preexisting chronic lymphocytic leukemia (CLL) or as the chance occurrence of two unrelated tumors. The cellular characteristics of the neoplastic clone involved in the CLL phase and the subsequent NHL were investigated in a patient in whom Richter syndrome developed. Methods. Cell analysis was performed with immunofluorescence, histologic analysis, DNA extraction, and Southern blot analysis. Results. The separated CLL and NHL B‐cells from blood and bone marrow, as well as the neoplastic cells in autopsy specimens of the organs affected by NHL, particularly the brain, were found to express the same light chain of surface immunoglobulin (SIg). The change MD — M in the SIg heavy‐chain expression and the appearance of cytoplasmic IgMk suggested isotype switching simulating that observed on the final phases of primary B‐cell differentiation. This hypothesis was confirmed by Southern blot analysis of DNA from blood cells in the CLL phase and in Richter transformation, which showed that the two cell populations had identical Ig gene rearrangement. Conclusions. The NHL in the patient in this study represented a malignant progression of CLL, not a second lymphoid malignancy.

Together with serum ferritin, erythrocyte ferritincan be a valuable diagnostic tool for evaluating the degree of impaired iron metabolism in different diseases. We collected peripheral blood samples from 64 subjects (22 healthy volunteers, 20 patients with hereditary hemochromatosis, and 22 patients on regular hemodialysis with secondary anemia) to evaluate whether an immunoenzymatic method generally used for serum ferritin can also be used to determine erythrocyte ferritin levels under various conditions of body iron status. Serum and erythrocyte ferritin levels were assayed in parallel using a microparticle enzyme immunoassay (MEIA) IMx-Ferritin kit and an IMx analyzer. The inter-assay imprecision of the serum and erythrocyte ferritin assays was 4.9% and 5.05%, the intra-assay imprecision was 2.2% and 2.3%, and the mean recovery was 102% (range 96-105%) and 101% (range 99-105%), respectively. Both serum and erythrocyte ferritin assays showed a detection limit of 1 microg/L and good linearity (R(2) = 0.99) in the intervals 13.9-443 and 3.9-135.6 microg/L, respectively. Our findings demonstrate that the IMx-Ferritin assay currently used to measure serum ferritin levels can also be adopted to measure erythrocyte ferritin insofar as it clearly discriminates high and low erythrocyte ferritin levels in cases of both iron overload and deficiency.

Radiosensitivity of lysosomes was investigated in vitro in different gaseous atmospheres. Results show a higher sensitivity when X-irradiation was performed in nitrous oxide. Possible reasons for this observation are considered.