[Nephelometry or turbidimetry for the determination of albumin, ApoA, CRP, haptoglobin, IgM and transthyretin: which choice?]. / Turbidimétrie ou néphélémétrie: quel choix pour les dosages de l'albumine, l'ApoA, la CRP, l'haptoglobine, l'IgM et la transthyrétine?

Nephelometry, which is considered as the reference method for serum proteins determination requires a specific equipment. The majority of protein determinations are therefore carried out on biochemistry automats using turbidimetry. The objective of a CNBH group (Collège national de biochimie des hôpitaux) was to compare nephelometry and turbidimetry for 7 automats: 2 nephelometers, the BN Prospec (Dade-Behring) and Immage (Beckman-Coulter) and 5 biochemistry systems using turbidimetry, the Integra and Modular (Roche Diagnostics), the LX20 (Beckman-Coulter), RXL (Dade-Behring) and AU (Olympus). The study was based on the determination of sera collections (albumin, ApoA, CRP, haptoglobin, IgM, transthyretin) of 140 samples each: 110 limpid samples and 30 samples called HLI (hemolytic, lipemic or icteric). Fifteen hospitals took part to this work. An ANOVA analysis on limpid samples and quality control sera concluded to an "automat" effect for the 6 tested proteins but did not show a "method" effect, (i.e. nephelometry versus turbidimetry). On the other hand, the transferability of the results was expected to be better and an effort on the choice of the antibodies and the standardization procedures should be made.

Recombinant gamma interferon provokes resistance of human breast cancer cells to spontaneous and IL-2 activated non-MHC restricted cytotoxicity.

Natural and lymphokine activated killer cells (NK and LAK) are believed to play an important role in the control of tumour progression and metastasis. Their specific receptors on tumours cells are still unknown. Several studies suggest that these cells recognise and eliminate abnormal cells with deleted or reduced expression of MHC class I molecules. Previous reports suggest that interferons (IFN), by increasing MHC class I expression on target cells, induce resistance to killing by NK cells. We investigated the role of MHC molecule expression by two human breast cancer cell lines T47D and ZR75-1 in their susceptibility to NK and LAK cells. These two cell lines spontaneously express low levels of HLA class I antigens but no HLA class II molecules. After IFN-gamma treatment they both overexpressed MHC class I and de novo expressed class II molecules as detected by flow cytometry, quantified by a radioimmunoassay and analysed by two-dimensional gel electrophoresis. Opposed to untreated cells these IFN-gamma treated cells were resistant to NK and LAK lysis. Furthermore, preincubation of IFN-gamma treated breast cancer cells with F(ab')2 fragments of monoclonal antibodies to HLA class I and HLA class II molecules was unable to restore lysis. In contrast, several complete monoclonal antibodies including anti-HLA class I and HLA class II induced the lysis of target cells whether or not they had been treated by IFN-gamma. The therapeutic use of monoclonal antibodies directed against antigens expressed on tumour cells (ADCC) in conjunction with interferon therapy should be discussed in lymphokine-based strategies for treatment of cancer patients.

TCR gamma delta bearing lymphocyte clones with lymphokine-activated killer activity against autologous leukemic cells.

Activated T lymphocytes with the T-cell receptor (TCR) gamma delta (CD3+ and TCR delta 1+) exhibit strong cytotoxic activity against the standard natural killer (NK) and lymphokine-activated killer (LAK) sensitive target cells. In order to test the cytotoxic activity of gamma delta T lymphocytes against autologous leukemic cells, 84 clones of gamma delta T lymphocytes were obtained from the peripheral blood of three acute lymphoblastic leukemia (ALL) patients. Forty-four of these T-cell clones were active against an LAK-sensitive cell line and the other 40 were active against K562, an NK target cell line. In each of the three patients, cytotoxic clones against autologous leukemic cells were obtained. Among the 84 clones, ten were able to kill autologous tumor cells, including eight that lyse the LAK-sensitive target and two with NK activity. The clones were highly cytotoxic, stable, and easily expanded in large quantity.

Human CD3 gamma delta + activated lymphocytes exhibit killer activity in vitro against autologous leukemic cells.

TCR gamma delta expressing T cell clones are able to exhibit in vitro strong cytolytic activity against cultured tumor cell lines as the myeloid K562 or the Burkitt's lymphoma Daudi cell line. We investigate the possibility of developing TCR gamma delta bearing T cell lines from peripheral blood of 2 leukemic patients in complete remission in order to study their ability to kill autologous leukemic cells. T lymphocyte clones are obtained by limiting dilution of lymphocytes from the blood of patients with an acute lymphoblastic leukemia (ALL). The T cell clones are first selected for their CD8- CD4-phenotype and then for their ability to react with the monoclonal antibody anti-CD3 without presenting reactivity with a monoclonal antibody directed against the TCR alpha beta. Further biochemical studies have indicated that the CD3 associated structure expressed on the cell membrane of these T cell clones is a gamma delta heterodimer. Functional analysis have indicated that these cloned cells are able to kill in a classical cell mediated lysis assay the autologous leukemic cells only when also LAK activity is observed. Thanks to this clonal expansion 10(10) cells/week indefinitely only 1 sample of peripheral blood will be necessary. Would these results be found with other leukemic patients, we propose to use this procedure for a possible application of killer cells for maintenance therapy of leukemia.

An anti-I cold auto-agglutinin enhanced in the presence of sodium azide.

Difficulty in determining the ABO blood group led to the discovery of an anti-I cold auto-agglutinin in the serum of a blood donor. The peculiarity of this antibody is that its activity is enhanced in the presence of a preservative found in manufactured anti-sera: sodium azide. At 4 degrees C, the auto-antibody agglutinates RBCs even without NaN3 but the drug increases its effect in the cold. At 22 degrees C, the drug is necessary for the adsorption of the antibody on red cells.