Analytical Performance of 10 High-Volume Clinical Chemistry Assays on the Alinity c System.

BACKGROUND: Early access for routine testing with the Alinity c clinical chemistry system (Abbot Laboratories) presented the opportunity to characterize the analytical performance of multiple analytes across clinical laboratories in Europe. METHODS: A total of 8 laboratories from 7 European countries evaluated 10 high-volume chemistry assays on the Alinity c system for imprecision, linearity, and accuracy by method comparison to the routine ARCHITECT (Abbott Laboratories) method. RESULTS: Within-run precision was less than 4% coefficient of variation (CV), with total imprecision less than 5.6% CV for 5- and 20-day evaluations. Linearity met expectations, and method comparison showed strong correlation between the Alinity and ARCHITECT methods, with overall linear correlation coefficient between 0.980 to 1.000 and slopes of the regression line between 0.963 and 1.034. Mean percentage difference between the results of assays run on the ARCHITECT and the Alinity ranged between -1.7% and 2.15%. CONCLUSIONS: Our results demonstrated acceptable key analytical performance across all assays tested at each participating laboratory.

Autoantibodies in patients with monoclonal gammopathies.

Although autoantibody activities are rather often associated to monoclonal gammopathies, only monoclonal immunoglobulins of the IgM isotype are really directed against autoantigens that are often polysaccharides or are formed by highly repetitive structures. This strict association is frequently revealed also by clinical manifestations of the autoimmune response generated by the monoclonal macroglobulin. Most monoclonal immunoglobulins of non-IgM isotype are instead totally inactive toward self-antigens, the autoantibody activity being instead associated, if present, to polyclonal immunoglobulins. Although the same BAFF/APRIL system is involved in perpetuation of humoral autoimmunity as well as in stimulation of clonal B-cell expansion, the autoimmune commitment of B cells of a non-IgM isotype is hardly compatible with their possible involvement in an uncontrolled proliferation pathway, whose prerequisite is the homing of these B cells to the bone marrow compartment. The IgM-secreting cells appear instead to possess a much lower tendency, and/or a looser requirement, for their homing in the bone marrow prior to their actual proliferation. This may explain the quite different consequences, in terms of autoimmunity, between IgM and non-IgM paraproteinemias.

Psychological stress affects response to sublingual immunotherapy in asthmatic children allergic to house dust mite.

While the clinical and immunologic efficacy of sublingual immunotherapy (SLIT) in allergic diseases has been extensively demonstrated, some patients display a poor clinical response. Psychological stress has been shown to play a role in atopy and also to affect response to immunomodulating therapies such as vaccination with microbial antigens. This study addresses the possibility of response to SLIT being affected by psychological stress. Forty children with mild asthma caused by allergy to Dermatophagoides pteronyssinus and farinae were subjected to SLIT and then divided after 6 months into two groups based on the results of the stress integrated measure (SIM) test: group 1 (24 stressed patients, mean SIM value of 60.1) and group 2 (16 non-stressed patients, mean SIM value of 7.6). There was also a higher prevalence of psychosocial stressing factors (divorced/absent parents, low income households, non-working parents) among stressed patients. The symptom score, peak expiratory flow (PEF), forced expiratory volume in 1 s (FEV(1)) and serum eosinophie cationic protein (ECP) concentration were evaluated at both times. The serum concentration of neuroendocrine parameters [prolactin, cortisol, adrenocorticotropic hormone (ACTH)] was also measured after 6 months of therapy. While all the clinical parameters and ECP concentration improved after SLIT, symptom score, PEF and ECP showed a significantly greater improvement in non-stressed patients. The concentration of neuroendocrine parameters was significantly increased in stressed patients. Our findings show that psychological stress can affect response to SLIT also in allergic subjects and are consistent with data recently reported showing a correlation between stress and poor response to antimicrobial vaccines. Our data also suggest that stress evaluation may become a useful prognostic factor in immunotherapy.