Two-site automated chemiluminescent assay for measurement of immunoreactive renin.

Measurement of renin is important for the clinical assessment of hypertensive patients and for the screening for primary aldosteronism. The aim of this study was to evaluate the performances of an automated immunoassay for measurement of immunoreactive renin. Functional sensitivity, in vitro stability, and reference values were determined. Method comparison with the plasma renin activity assay was also performed. Our results demonstrate that the Liaison(®) direct renin assay may assist the clinician in the assessment of hypertensive patients and in the screening for primary aldosteronism.

Automated immunoassay for reliable measurement of sex hormone binding globulin (SHBG).

BACKGROUND: Sex hormone binding globulin (SHBG) is important for the transport and regulation of distribution of sex steroids. METHODS: The performance of the Architect SHBG automated immunoassay in comparison to radioimmunoassay was evaluated using 62 patient specimens. Furthermore, specimen from 100 healthy individuals were used to establish a preliminary reference interval for this automated assay. RESULTS: The assay has demonstrated overall good analytical performance and was significantly correlated with the reference method. CONCLUSIONS: The Architect SHBG assay is a good method for routine measurement of SHBG circulating levels.

CRP measurement: does the assay matter in hemodialysis patients?

BACKGROUND: The serum level of C-reactive protein, an acute-phase marker of systemic inflammation, has been shown to predict cardiovascular events in the general population and cardiovascular and total mortality in hemodialysis patients. High-sensitivity CRP assays (hs-CRP) have been used in numerous studies. We hypothesized that the level of CRP as measured by the conventional assay (c-CRP) would predict mortality in hemodialysis patients with an accuracy similar to that of high-sensitivity assays. METHODS: In April 2001 CRP serum level was measured with both a conventional and a high-sensitivity assay in 102 prevalent hemodialysis patients. Mortality was prospectively monitored over 6 years. RESULTS: 49 patients (48%) died during follow-up. With both assays, almost 2/3 of patients had high CRP levels (> 1 mg/dl). Survival at 6 years was significantly lower in patients with high CRP levels, no matter which assay was used (31.5% for patients with high hs-CRP and 27.3% for patients with high c-CRP vs 48.4% for patients with low hs-CRP and 47.1% for patients with low c-CRP). Cardiovascular mortality was also higher in patients with high CRP levels, whatever the type of assay (conventional or high sensitivity) used. The correlation between the two tests was excellent. CONCLUSION: CRP level, measured by a conventional inexpensive assay, is predictive of mortality in hemodialysis patients.

[Serum protein electrophoresis: comparison of capillary zone electrophoresis Capillarys (Sebia) and agarose gel electrophoresis Hydrasys (Sebia)]. / Electrophorèse des protéines sériques: comparaison de la technique en capillaire de zone Capillarys (Sebia) et de l'électrophorèse en gel d'agarose Hydrasys (Sebia).

Since several years, serum proteins electrophoresis became a routine analysis, mainly performed by agarose gel electrophoresis, frequently semi-automated. We compared the new fully automated capillary electrophoresis system from Sebia, Capillarys, with our reference method, agarose gel electrophoresis Hydrasys (Sebia). This study focused on the evaluation of both the analytical performances and some practical aspects such as ease of use, rapidity, costs. It appears clearly from that study that both methods give similar results for the detection of monoclonal proteins. We notice that the capillary electrophoresis (Capillarys) displays higher sensitivity (97.2%) than the agarose gel electrophoresis Hydrasys (93.5%), however with a lower specificity (93.7 versus 98.9%). On the other hand, the Capillarys method displays obvious practical advantages such as full automation, ease of use and rapidity.

Ly-6A/E induction by interleukin-6 and interleukin-9 in T cells.

Interleukin-6 (IL-6) is active in the early steps of T cell activation and confers IL-2 responsiveness. In this work, we used EL4 T lymphoma to identify IL-6 target genes in T cells. By differential screening of a cDNA library, we found that IL-6 induced the expression of Ly-6A/E, a GPI-anchored cell surface protein reported to be a regulator of T cell activation. In addition to IL-6, IL-9 and IFN-gamma induced Ly-6A/E expression in EL4 and BW5147 cells. We showed that both IL-6 and IL-9 mediated the transcriptional activation of Ly-6A/E through a GAS element in the Ly-6A/E promoter, which was able to bind STAT1 and STAT3, transcription factors activated by these cytokines. IL-6 had a similar effect in freshly isolated normal T cells, and dramatically increased their proliferation upon Ly-6A/E stimulation. Taken together, our data suggest that Ly-6A/E induction takes part in the T cell activation program initiated by IL-6.

The effects of interferon-alpha on the proliferation of CML progenitor cells in vitro are not related to the precise position of the M-BCR breakpoint.

We investigated the effects of brief (2 h) and continuous exposure to recombinant interferon-alpha (2a) (rIFN-alpha) on the proliferation of primitive (blast colony-forming cells, Bl-CFC) and committed myeloid progenitor cells (BFU-E and GM-CFC) derived from blood and bone marrow of patients with chronic myeloid leukaemia (CML) and normal subjects. In all three clonogenic assays, rIFN-alpha suppressed colony formation in a dose-dependent manner. No differences were detected in the proliferation of CML or normal Bl-CFC and GM-CFC exposed to rIFN-alpha. Erythroid colony formation by normal, but not by CML BFU-E, was inhibited by relatively low concentrations (100 U/ml) of rIFN-alpha. However, in patients whose blood or marrow contained a mixture of Philadelphia chromosome (Ph)-positive and Ph-negative BFU-E, cytogenetic analysis of individual erythroid colonies showed no differential inhibition by rIFN-alpha. We found no difference in the sensitivity to rIFN-alpha of GM-CFC from patients whose leukaemic cells expressed BCR/ABL mRNA with the b2a2 junction and that of GM-CFC from patients with the b3a2 mRNA. We conclude that (1) rIFN-alpha does not have a significant leukaemia-specific effect on the progenitor cells detected in these assays, and (2) the sensitivity of CML GM-CFC to rIFN-alpha is independent of the type of BCR/ABL message present in the cells. The clinical efficacy of rIFN-alpha could be due to selective toxicity to cells not assayed in this study, to effects on accessory cells or to alterations induced in progenitor cell/stromal cell interactions.

Detection of residual BCR/ABL transcripts in chronic myeloid leukaemia patients in complete remission using the polymerase chain reaction and nested primers.

We sought evidence of BCR/ABL transcripts in the peripheral blood of nine CML patients in complete clinical and cytogenetic remission after treatment by bone marrow transplantation (BMT) or interferon and in one patient who entered spontaneous remission. Six patients were investigated at different times during their follow-up. We compared results obtained with the polymerase chain reaction (PCR) using (a) a single-stage PCR comprising 30 cycles of amplification with selected oligomers, and (b) a two-stage procedure in which the reaction product from the first stage was subjected to a further 30 cycles with nested amplimers. Special care was taken to assess contamination, including for each patient simultaneous co-extraction of a negative control. Blood cells from all patients showed no evidence of BCR/ABL transcripts in the one-stage PCR but 9/17 specimens were positive in the two-stage procedure. Patients in complete remission for a long time (greater than 2 years) appeared negative. These results serve in part to explain the discordant findings reported in other studies and emphasize the importance of carefully selecting the technical conditions most likely to give results that are prognostically relevant for individual patients.