Atypical lymphocytic leukemia and mantle cell lymphoma immunologically very close: flow cytometric distinction by the use of CD20 and CD54 expression.

Integration of morphological and immunophenotypic data is critical in achieving diagnosis accuracy and minimising interobserver interpretative discrepancies. The aim of this work was to compare the immunophenotype and the morphology of chronic lymphocytic leukaemia and mantle cell lymphoma, to help in the differential diagnosis of CD5 positive monoclonal B cells. Frozen/thawed samples from 91 patients were analysed retrospectively. Fresh samples from 17 mixed/atypical CLL and 13 MCL were tested to corroborate the results. Markers were analysed as percentage (%) of positive B lymphocyte subpopulation, and in terms of median fluorescence intensity (MFI). Matutes's CLL score clearly allowed distinguishing between classical CLL on the one hand, and atypical CLL and MCL on the other hand. The percentage of CD54-positive cells and the median fluorescence intensity of CD20 and CD54 were the only parameters which were significantly higher in MCL than in atypical CLL (P < 0.05), allowing an immunological distinction between these two entities. Nevertheless, due to a quenching problem when using CD20 and CD54 together, and because CD18 showed a statistically different expression between classical and atypical CLL, the combination of CD18/CD54 has been preferred and showed a different pattern in the three entities. Immunophenotyping could be helpful in the differential diagnosis of CD5-positive B cell chronic lymphoproliferative disorders with atypical features that do not fit exactly into any of the morphologic proposed groups.

Cytogenetic analysis of B cell chronic lymphoid leukemias classified according to morphologic and immunophenotypic (FAB) criteria.

609 patients with B cell chronic lymphoproliferative disorder were studied with the primary aim of analyzing the cytogenetic profile of B cell chronic lymphocytic leukemias and, if possible, define correlations with FAB classification of these diseases. Morphological and immunological studies were performed according to criteria proposed by the FAB group. A panel of monoclonal antibodies, including at least sIg, CD19, CD5, and FMC7 was used. Interpretations of morphology and cytogenetics were made independently. When applying strict FAB criteria 65% of the cases could be classified. Most of them (44%) were chronic lymphocytic leukemia (CLL). The cases not satisfying strict FAB criteria could be divided into two groups: one closely related to CLL, and here defined as atypical CLL (aCLL) (21%) and another group consisting of patients with leukemic manifestations of B cell non-Hodgkin's lymphoma (LL) (14%). Analyzable metaphases were obtained in 89% of patients. Clonal abnormalities were present in 35% of patients. The most frequent chromosomal changes were abnormalities of chromosome 11q (60 cases), trisomy 12 (46 cases) and structural rearrangements of chromosome 14q (44 cases). Statistical associations with FAB subtypes were found: aCLL and trisomy 12 (P < 0.00001); mantle zone lymphoma (MZL) and t(11;14) (P < 0.00001) and del(6)(q) (P < 0.0001); CLL/mixed cell type and del(6)(q) (P < 0.002); follicular lymphoma and t(14;18) (P < 0.00001); splenic lymphoma with villous lymphocytes and del(7)(q) (P < 0.0004); leukemic lymphoma (LL) with rearrangements in chromosome 9q (P < 0.0001) and trisomy of 3 (P < 0.001). Chronic lymphocytic leukemia was not statistically associated with any specific chromosomal abnormality. However, this subtype showed a high incidence of del(11)(q) and rearrangements of 13q. This study confirms the value of cytogenetic investigation in the diagnosis of these disorders and may provide some new elements for future refinement of the FAB classification in mature B cell lymphocytic disorders.

Potentiation of antitumor effects of cyclophosphamide derivatives in B-chronic lymphocytic leukemia cells by 2-chloro-2'-deoxyadenosine.

Because 2-chloro-2'-deoxyadenosine (CdA) is active in B-chronic lymphocytic leukemia (B-CLL), and may interfere with DNA repair, we investigated the potentiating effect of CdA on the cytotoxicity induced in vitro in B-CLL lymphocytes by cyclophosphamide (CP) derivatives, which induce DNA damage by DNA cross-linking. Exposure to CdA at clinically achievable concentrations for 2 h, followed by mafosfamide (MAF) or 4-hydroxycyclophosphamide (4HC) for 22 h, resulted in synergistic cytotoxicity in the majority of B-CLL samples tested. Synergy between CdA and MAF was observed in cell samples of sensitive/untreated patients, as well as in cells of resistant/pretreated patients, particularly at the highest concentrations of MAF. In the cells treated with CdA and MAF, we observed loss in ATP and hallmarks of apoptosis, as evidenced by cellular morphology and high molecular weight DNA fragmentation. The synergy could be explained neither by an influence of MAF on the phosphorylation of CdA, nor by an increase in the incorporation of CdA into DNA in the presence of MAF. The in vitro synergy between CdA and CP derivatives provides a rationale for the use of this association in B-CLL patients.

[A particular hereditary anemia in a two-month-old infant: elliptocytosis]. / Une forme particulière d'anémie constitutionnelle chez un nourrisson de deux mois: l'elliptocytose.

We report the case of a 2.5-month-old infant with severe anaemia discovered fortuitously during an acute febrile illness. The patient was admitted because of a septic arthritis of the knee. Initial biology showed a 3.5 g/dl haemoglobin concentration. The anaemia was microcytic and hypochromic, with obvious haemolysis and reticulocytosis. Standard analysis was not contributive. Further investigations allowed the diagnosis of elliptocytosis. The patient was treated by antibiotics, orthopaedic measures and iterative transfusions. Now, 18 months from the initial episode, she is in good health. With this history, we discuss the clinical process facing severe anaemia during infancy and review the particularities of such uncommon congenital anaemia. Elliptocytosis is a haemolytic anaemia caused by congenital anomalies of the erythrocyte membrane. Diagnosis requires morphological studies of the red blood cells on peripheral blood smear. The disease is often overlooked by membrane protein electrophoresis. The condition is heterogeneous concerning clinical, biochemical and genetic aspects. Most of the cases are linked to mutations of the alpha-spectrin gene, in autoassociation regions. Search of spectrin and protein 4.1 genes mutations can confirm the diagnosis but is not routinely performed.

Mature plasma cells as indicator of better prognosis in multiple myeloma. New methodology for the assessment of plasma cell morphology.

The relationship between plasmablastic cells and outcome in multiple myeloma (MM) has been established for nearly 15 years. But the assessment of these cells is not easy to perform and it allows the identification of only a small proportion of patients. We investigated the plasma cell morphology using a progressive evaluation of consecutive criteria: nucleolus, chromatin and nuclear-cellular ratio (N/C). The combination of these three items produces a subclassification where four cellular subtypes identify 93% of the plasma cells, and these subtypes are related to the outcome. The interest of this methodology is to be based on the mature plasma cells that are easier to identify than the plasmablastic cells. These new cell subtypes introduce a new classification for patients: Group 1 includes patients with at least 66% mature plasma cells (P000). Both Group 2 and 3 have less than 66% P000 and are separated by their degree of maturation (Proplasma I > or = Proplasma II + plasmablastic). The distinction of these three groups of patients is highly related to the prognosis (P < 10(-4)). These results have been confirmed on a second group of patients coming from a different institution. In conclusion, we propose a new methodology for the plasma cell evaluation in MM, that is based on the morphological criteria and that has the advantage of identifying an intermediate (30%) subgroup of patients with a prognostic significance.

A promising model of primary human immunization in human-scid mouse.

The engraftment of human peripheral blood mononuclear cells (Hu-PBMC) from adult donors in scid mice has been published by MOSIER et al. in 1988. The possibility to obtain a secondary human immune response in human-scid mice has also been reported but attempts to induce a primary human immune response still remain difficult to achieve. In this work, an antigen (Canine albumin) or a hapten (DNP) was coupled with tetanus toxoid, an antigenic protein against which our human donors already had memory T cells through vaccination. In this way, hu-scid mice immunized with coupled DNP-tetanus toxoid (TT-DNP) or coupled Canine albumin-Tetanus toxoid (Calb-TT) mounted a specific human immune response anti-DNP or anti-Canine albumin (Calb) respectively. A secondary human immune response anti-tetanus toxoid was also detected in the sera of hu-scid mice immunized with product containing TT but not in the sera of those injected with PBS alone. The scid mice grafted with Hu-PBMC from a TT naive donor and challenged with Calb-TT or Calb alone failed to produce specific anti-Calb antibodies. These observations demonstrate that memory T cells can give a substantial help to naive B cells which interact with them for obvious B cell activation and differentiation into plasma cells. This model of immunization might be useful for other antigens of choice, allowing the production of human monoclonal antibodies, in combination with a suitable system of immortalization. Attempts to immunize human cells in scid mice against DNP coupled to LO-BM2 (a rat monoclonal antibody anti-human IgM) failed to induce a specific human response either anti-rat immunoglobulins (Igs), or anti-DNP and led to a decrease of human Ig production in hu-scid. We also immunized hu-scid mice against ovalbumin alone but, only in some cases, a low specific human immune response was observed, so this system seems to be unreliable.

A panel of antibodies for the immunostaining of Bouin's fixed bone marrow trephine biopsies.

AIMS: To assess a panel of antibodies on Bouin's fixed bone marrow trephine (BMT) biopsies. These biopsies are widely used in routine diagnosis of various haematological malignancies and may be the sole material available in many centres; however, information regarding the immunostaining of this material is lacking. METHODS: Biopsies were taken from 72 patients presenting with various haematological malignancies (leukaemia, 38; lymphoma, 14; multiple myeloma, 20). A panel of antibodies was assessed on Bouin's fixed BMT biopsies by the alkaline phosphatase-antialkaline phosphatase method. RESULTS: Three B (MB2, LN-2, Ki-B5) and two T cell lineage antibodies (UCHL-1, CD3-r) reliably identified lymphoid cells, while MPO-r, Leu-M1/CD15, and KP-1/CD68 recognised cells from the myeloid or histiocytic/macrophage series. Reed-Sternberg cells were stained by LN-2, Leu-M1, and CD30. Antibodies specific for plasma cells (VS38) and hairy cells (DBA.44) gave a variable pattern of staining. Among the proliferation markers, proliferative cell nuclear antigen but not Ki-67 related antibodies were effective. CONCLUSION: This study presents a panel of antibodies with reactivity not restricted to common fixatives that are also suitable for Bouin's fixed BMT biopsies.

Translocation (Y;1)(q12;q12) in hematologic malignancies. Report on two new cases, FISH characterization, and review of the literature.

Translocation (Y;1)(q12;q12) is a rare cytogenetic anomaly occurring in hematologic disorders thought to affect stem cells. We report here on two new cases, one end-stage myelofibrosis and one chronic myelomonocytic leukemia. The translocation breakpoints were assessed by conventional cytogenetic techniques in both cases and by FISH in the second case. A partial trisomy of the 1q21-qter region could be demonstrated. The data of the literature are reviewed and the possible pathogenetic mechanisms are discussed.

The thymus of Nu/+ mice.

At one month, the thymus weight of NMRI mice heterozygous for the Nu gene was lower than that of the wild type. However, the thymic structure was normal and no significant anomalies at the ultrastructurallevel could be found either in epithelial cells or in thymocytes. Stereologic data showed that the loss of weight was only due to a decrease of the lymphoid population, whereas the absolute number of epithelial cells was unmodified. Several hypotheses that could explain the reduced number of thymocytes were discussed.

Acute leukemia diagnosis aid using multicriteria fuzzy assignment methodology.

We recently developed a new multicriteria classification method called PROAFTN to help medical diagnosis. The aim of this paper is to present the application of the proposed method for the diagnosis of acute leukemia (AL). The implementation of PROAFTN was carried out on cytological data of 108 cases of AL, using the classification rules of French, American and British hematologists, and was then applied on an independent test set of 83 cases of AL. Forty-seven features, obtained by examining patients' bone-marrow smears with light microscope, defined each case. In order to determine the percentage of correct classifications for each subtype of AL, we compared our results with the clinical diagnosis given previously by the hematologist. 96.4% of the cases were correctly classified by the program, suggesting that the method yields good results in terms of discrimination between AL subtypes.

Relapsing visceral leishmaniasis in a HIV-1 infected patient with advanced disease.

Leishmaniasis, an intracellular protozoal infection in which tissue macrophages are targeted, is transmitted by female sandfly bite and occurs in 98 countries. Visceral leishmaniasis (VL) is the clinical form of leishmaniasis most frequently associated with HIV, especially in Europe. Both diseases have a synergistic detrimental effect on the cellular immune response. Treatment of VL in patients with underlying HIV-infection is associated with lower cure rates, higher rates of drug toxicity, higher relapse rates and greater mortality than treatment of VL in immunocompetent patients. We report the case of a HIV-1 infected patient with advanced disease who presented VL with multiple relapses. This case highlights the difficulties of treating VL in patients with HIV co-infection.

External quality assessment in the measurement of haemoglobin by blood gas analysers in Belgium.

OBJECTIVE: The Belgian national External Quality Assessment Scheme (EQAS) for haematology organized a survey to assess the reliability of haemoglobin (Hb) measurements with the blood gas analysers (BGAs) currently available in Belgian hospitals. MATERIAL AND METHODS: All hospital laboratories received two specimens of fresh EDTA anticoagulated whole blood and were asked to determine the Hb concentration using both the conventional haematology analyser (HA) and all BGAs in the hospital. Ninety-seven hospital laboratories participated in the study and a total of 166 results were reported. The BGAs used (grouped according to technology) were Rapidlab 845, 855, 865 (Bayer 1, n = 41), Rapidlab 1245, 1265, Rapidpoint 405 (Bayer 2, n = 19), GEM Premier 3000 (Instrumentation Laboratory, IL, n = 13), ABL 500 and 600 series (Radiometer 1, n = 13), ABL 700 and 800 series (Radiometer 2, n = 35), Omni C, S5 (Roche 1, n = 7), Omni 3, 6, 9, S2, S4, S6 (Roche 2, n = 21). RESULTS: For the BGAs from Bayer, Radiometer and Roche, interlaboratory variation ranged from 0.6 % to 4.1 %, indicating good precision and close agreement between centres. A significant negative bias observed on the GEM Premier 3000 using the EDTA anticoagulated blood samples did not appear to be present in fresh heparinized whole blood samples. There was no significant difference in imprecision and bias between Hb measurements on BGA situated in and outside the central laboratory.

Multinucleate cells in thymus of C3H mice.

Multinucleate epithelial cells occur in the thymus of C3H mice. They are poorly differentiated and scarce, but are more numerous in the medulla than in the cortex. Their increase in number with age is particularly significant between the first and the third months especially for cells with a large number of nuclei, and may be related to thymic involution. Viral particles of type C, similar to those described in murine leukemias, are found in mono- and multinucleate medullary epithelial cells.

Thymus histogenesis in C3H mice.

The histogenesis of the mouse thymus was studied by means of light and electron microscopy in an attempt to clarify the simultaneous development of stromal and lymphoid cell populations. On the twelfth day of embryonic life, the thymus primordium was composed principally of undifferentiated epithelial cells and some lymphoblasts. In the developing cortical regions, lymphoblasts accumulated rapidly, stretching the epithelial cells which became stellate in shape. The latter contained multivesicular bodies and, from the sixteenth day on, also typical clear vacuoles. Medullary regions were prefigurated as soon as day 13 by several areas wherein lymphoblasts were sparse and epithelial cells were closely associated, with numerous desmosomes and abundant tonofilaments. On the sixteenth day, some epithelial cells in these regions were differentiated into globular cells, or formed Hassall's corpuscles and intra- or extracellular cysts. On the seventeenth day, the presence of interdigitating cells in the medullary areas completed cortico-medullary differentiation. On the eighteenth day, small cortical thymocytes differentiated and the thymus possessed all characteristics of an adult thymus. Thus, at birth, the histogenesis of the mouse thymus was achieved and the only further modification consisted in a gain of weight.

Thymic nurse cells: morphological study during their isolation from murine thymus.

Thymic nurse cells (TNC), which are multicellular complexes composed of epithelial cells and thymocytes, were obtained from C3H-mice thymuses. They were described by means of light and electron microscopy. The morphology of epithelial cells forming isolated TNC compared to that of small tissue fragments obtained by enzymatic digestion revealed that TNC could be derived from all parts of the thymus: cortex, corticomedullary junction and medulla, the cortex being their principal source. This variety of origin, the presence of several epithelial cells inside a single TNC, the presence of non-lymphoid cells, and the various locations of cleaved desmosomes confirmed that their aspect "in vitro" as round and sealed structures can be considered to be an artifact due to the isolation technique used. Indeed, during this procedure, they are formed by a process of wrapping of the epithelial cytoplasm around the tightly associated thymocytes. All three epithelial cell types: cortical reticular cells, medullary reticular cells, and medullary globular cells can form TNC.

High amylase activity in pleural fluid and primary bronchogenic adenocarcinoma.

We report a case of primary bronchogenic adenocarcinoma, complicated by pleural effusion, in which very high pleural amylase activity was found, whilst serum amylase was normal. Isoamylase determination showed a salivary-type amylase. Concerning the origin of this enzyme, ultrastructural study of the malignant cells obtained from the pleural fluid suggested a local amylase synthesis. The pathophysiological significance of electron-dense granules found in these cells is also discussed.