Insulin resistance is linked to a specific profile of immune activation in human subjects.

We tested the hypothesis that a particular immune activation profile might be correlated with insulin resistance in a general population. By measuring 43 markers of immune, endothelial, and coagulation activation, we have previously shown that five different immune activation profiles may be distinguished in 150 volunteers. One of these profiles, Profile 2, characterized by CD4+ T cell senescence, inflammation, monocyte, B cell, and endothelial activation, presented elevated insulinemia, glycemia, triglyceridemia, and γ-glutamyl transferase, a marker of liver injury, in comparison with other profiles. Our data are compatible with a model in which a particular immune activation profile might favor the development of insulin resistance and metabolic syndrome. In this hypothesis, identification of this profile, that is feasible with only 3 markers with an error rate of 5%, might allow to personalize the screening and prevention of metabolic syndrome-driven morbidities as liver steatosis.

Identification of distinct immune activation profiles in adult humans.

Latent infectious agents, microbial translocation, some metabolites and immune cell subpopulations, as well as senescence modulate the level and quality of activation of our immune system. Here, we tested whether various in vivo immune activation profiles may be distinguished in a general population. We measured 43 markers of immune activation by 8-color flow cytometry and ELISA in 150 adults, and performed a double hierarchical clustering of biomarkers and volunteers. We identified five different immune activation profiles. Profile 1 had a high proportion of naïve T cells. By contrast, Profiles 2 and 3 had an elevated percentage of terminally differentiated and of senescent CD4+ T cells and CD8+ T cells, respectively. The fourth profile was characterized by NK cell activation, and the last profile, Profile 5, by a high proportion of monocytes. In search for etiologic factors that could determine these profiles, we observed a high frequency of naïve Treg cells in Profile 1, contrasting with a tendency to a low percentage of Treg cells in Profiles 2 and 3. Moreover, Profile 5 tended to have a high level of 16s ribosomal DNA, a direct marker of microbial translocation. These data are compatible with a model in which specific causes, as the frequency of Treg or the level of microbial translocation, shape specific profiles of immune activation. It will be of interest to analyze whether some of these profiles drive preferentially some morbidities known to be fueled by immune activation, as insulin resistance, atherothrombosis or liver steatosis.

Monoclonal gammapathy <5 g/L: the interest of T/O ratio.

There is currently no consensus for the quantification and identification of weak gammaglobulin monoclonal spike. We conducted a study of 12 months including 410 serum protein electrophoresis (SPE) with suspected weak monoclonal spike in gammaglobulin area without anteriority, which led to the realization of an immunofixation (IF); 276 SPE has a weak spike in gammaglobulins (defined with perpendicular drop method (orthogonal (O) quantification <5 g/L) but only 157 (57%) has monoclonal immunoglobulin by immunofixation of serum. The monitoring of 50 true positive monoclonal immunoglobulins showed the stability of the spike at more than half of the patients and its disappearance in 28% of cases. The number of true positives spike raise when using the tangent skimming method quantification (T) rather than the orthogonal method (O). The distribution of true positives based on T/O ratio propose a 6% threshold below which a monoclonal immunoglobulin is rarely found (VPNR>6%=73.7%), and a 10% threshold above more than 80% of true positives are detected (VPPR>10%=94.4%). The use of the T/O ratio could i) help to predict the presence of an IM when low intensity spike is detected, and help to choose between the realization of an immunofixation or a control of SPE later; ii) be a key tool for an inter-laboratory harmonization of IM follow up.

Evaluation of two automated capillary electrophoresis systems for human serum protein analysis.

OBJECTIVES: We compared automated capillary electrophoresis (CE) systems Capillarys 2 from Sebia and V8 from Helena Biosciences Europe (Elitech) with the semi-automated Hydrasys-Hyrys agarose gel electrophoresis (AGE) from Sebia. DESIGN AND METHODS: We evaluated analytical performances and compared 129 fresh routine sera (group A) to 164 frozen pathologic samples with suspicion or antecedent of monoclonal component (MC) (group B). Immunofixation was then compared with immunotyping provided by both CE systems. RESULTS: Analytical performances from both CE systems have proven suitable results for clinical use, with within-run and between-run coefficients of variation inferior or equal to 5.2% and 7.7%, respectively. A good correlation was found between AGE and CE with r-value ranging from 0.81 to 0.96 for both CE systems. We observed high MC detection sensitivities (>85%) of in electrophoretogram readings for both CE systems. MC identification using CE systems provided suitable concordance with immunofixation, although failing to detect some IgM proteins or free light chains. CONCLUSIONS: Both Capillarys 2 and V8 are reliable automated CE systems for patient care.

Online high-efficiency haemodiafiltration achieves higher serum free light chain removal than high-flux haemodialysis in multiple myeloma patients: preliminary quantitative study.

BACKGROUND: Fast reduction of serum free light chain (FLC) levels correlate with renal recovery in cast nephropathy. Because convection has the capacity to remove proteins of higher molecular weights, we hypothesized that haemodiafiltration (HDF) would be superior to haemodialysis (HD) for FLC clearance. METHODS: We retrospectively identified all renal replacement therapy (RRT) sessions performed in multiple myeloma patients with pre- and post-treatment FLC measurements during a 2-year period. Using kinetic modelling, we calculated reduction percentages corrected for net ultrafiltration, effective clearances, net mass removal and Kt/V for both kappa (κ) and lambda (λ) serum FLC. RESULTS: We analysed 27 (10 HD and 17 HDF) RRT sessions realized in a total of six subjects. HDF resulted in higher FLC removal rates when compared to HD. Moreover, high-efficiency (i.e. substitution volume > 15 L/session) HDF demonstrated median efficient FLC clearances roughly twice superior to high-flux HD for both κ (59.0 versus 33.8 mL/min, respectively; P < 0.01) and λ (40.5 versus 19.7 mL/min, respectively; P = 0.02) FLC. In post-dilution HDF treatments, corrected FLC reduction percentages positively correlated with substitution volumes. Total plasma proteins increased during RRT in the HDF group. CONCLUSIONS: This preliminary quantitative study demonstrates the superiority of high-efficiency HDF over high-flux HD for serum FLC removal in multiple myeloma patients on RRT. No negative impact on total plasma proteins was noted.

An in vitro model of differentiation of memory B cells into plasmablasts and plasma cells including detailed phenotypic and molecular characterization.

Human plasma cells (PCs) and their precursors play an essential role in humoral immune response but are rare and difficult to harvest. We report the generation of human syndecan-1(+) and immunoglobulin secreting PCs starting from memory B cells in a 3-step and 10-day (D) culture, including a 6-fold cell amplification. We report the detailed phenotypic and Affymetrix gene expression profiles of these in vitro PCs as well as of intermediate cells (activated B cells and plasmablasts) compared with memory B cells and bone marrow PCs, which is accessible through an open web ATLAS (http://amazonia.transcriptome.eu/). We show this B cell-to-PC differentiation to involve IRF4 and AICDA expressions in D4 activated B cells, decrease of PAX5 and BCL6 expressions, and increase in PRDM1 and XBP1 expressions in D7 plasmablasts and D10 PCs. It involves down-regulation of genes controlled by Pax5 and induction of genes controlled by Blimp-1 and XBP1 (unfold protein response). The detailed phenotype of D10 PCs resembles that of peripheral blood PCs detected after immunization of healthy donors. This in vitro model will facilitate further studies in PC biology. It will likewise be helpful to study PC dyscrasias, including multiple myeloma.