Monoclonal expansion of immunoglobulin not-secreting CD5+ CD11c+ CD38+ B-cells in a rare case of chronic lymphoplasmacytoid leukaemia.

We present the clinical and immunological features of a rare case of chronic lymphoid leukaemia with lymphoplasmacytoid morphology. The patient was first admitted suffering from weakness, pallor, dyspnoea, marked splenomegaly, hepatomegaly and systemic lymphadenopathy and panhypogammaglobulinaemia. White blood cell count revealed important leukocytosis (220 x 10(9) WBC/l) with 2% neutrophils and 98% lymphoid cells showing lymphoplasmacytoid features, while lymphoid cells of identical morphology severely infiltrated the bone marrow and lymph nodes.

Lymphocyte subpopulations in pediatric age. Definition of reference values by flow cytometry.

In the present paper we have analyzed the age-related changes in the distribution and numbers per cubic millimeter of the circulating lymphocyte subpopulations. Lymphocyte subsets have been examined by monoclonal antibodies specific for surface antigens (namely CD2, CD3, CD4, CD8, CD16, CD20 and CD57) and flow cytometry in lysed peripheral blood of normal neonates (1-3 days old), 1-6 month, 7-12 month, 1-2 year old babies and 3-5 year, 6-10 year old children and young people up to 17 years of age. The results confirm the lymphocytosis at birth and at later stages of life and indicate that major changes in the distribution of lymphocyte subsets occur during the first two years of life; namely we have observed sharp increase of circulating B lymphocytes and prevalence of CD4+ T lymphocytes with high CD4/CD8 ratios in babies up to two years of age, compared to the values observed in normal adults.

Cytotoxic and immunotoxic effects of Fusarium mycotoxins using a rapid colorimetric bioassay.

A colorimetric MTT (tetrazolium salt) cleavage test was used to evaluate cytotoxicity of twenty-three Fusarium mycotoxins on two cultured human cell lines (K-562 and MIN-GL1) as well as their inhibitory effect on proliferation of phytohemagglutinin-stimulated human peripheral blood lymphocytes. The values of 50% inhibition of lymphocyte blastogenesis were very close to the 50% cytotoxic doses observed with the more sensitive cell line (MIN-GL1). T-2 toxin was the most cytotoxic with CD50 and ID50 values less than 1 ng/ml.

Ontogeny of human lymphocytes. Two-color fluorescence analysis of circulating lymphocyte subsets in fetuses in the second trimester of pregnancy.

By using monoclonal antibodies, two-color immunofluorescence techniques and flow cytometry, we evaluated the surface marker phenotypes of lymphocyte subsets in cord blood samples from fetuses in the second trimester of pregnancy. The results indicate that cells of the T-, B- and NK-cell lineages as well as precursor cells can be detected in fetal blood at 18-20 weeks of gestation. At this stage of development, variable proportions of T and B lymphocytes express surface molecules, such as the CD1, CD10, CD38, CD45RA, indicative of a precursor or 'naive' state; on the other hand, the CD57 molecule is not detectable on the membrane of NK and T cells, and the RO isoform of the CD45 leukocyte antigen is synthesized by a low percentage of T cells.

[Effect of lymphokines produced by human T-T hybridomas on the proliferation of normal and neoplastic B lymphocytes].

Human T-T hybridomas were obtained by fusing T lymphoblasts of the azaguanine-resistant CEM-6 cell line and PHA-activated normal T lymphocytes. After 4 weeks of culture with selective media, proliferating hybrid cells were cloned by limiting dilution. Several clones were obtained and one of them (F2) was shown to secrete a lymphokine with inhibitory activity on the proliferation of an EBV-transformed B cell line, of normal B lymphocytes, as well as of mitogen activated normal T lymphocytes.