Administration of intravenous immunoglobulin (IVIG) in vivo—down-regulatory effects on the IL-1 system

Modulation of the cytokine network may be of importance for the beneficial effects of therapy with IVIG seen in a wide range of immune-mediated disorders. In the present study we investigate the effect of IVIG administration in vivo on the IL-1 system in 12 patients with primary hypogammaglobulinaemia. Before IVIG infusion these patients had significantly elevated levels of IL-1α and IL-1β both in plasma and in supernatants from peripheral blood mononuclear cells (PBMC) compared with healthy controls. After one bolus infusion with IVIG (0.4 g/kg) we found a significant change in the profile of the components of the IL-1 system: a marked increase in levels of IL-1 receptor antagonist (IL-1Ra) and neutralizing antibodies against IL-1α, a moderate decrease in levels of IL-1α, IL-1β and soluble (s) IL-1 receptor type I and a significant increase in sIL-1 receptor type II levels. These changes were found both in plasma and in PBMC isolated after IVIG administration. Furthermore, pooled serum obtained after IVIG infusion suppressed lipopolysaccharide- and staphylococcal enterotoxin B-stimulated, but not phorbol myristate acetate-stimulated, release of IL-1α and IL-1β from PBMC isolated from healthy controls. Finally, these changes in circulating levels of various IL-1 modulators after IVIG infusion appeared to cause a significantly impaired ability of IL-1 to stimulate PBMC for tumour necrosis factor-alpha release. Our findings suggest that IVIG administration may not only down-regulate the activity in the IL-1 system, but also hamper IL-1 stimulation of PBMC

A Novel Targeted Screening Tool for Hypogammaglobulinemia: Measurement of Serum Immunoglobulin (IgG, IgM, IgA) Levels from Dried Blood Spots (Ig-DBS Assay)

PURPOSE: To develop an assay to quantify serum immunoglobulin (IgG, IgM, IgA) levels using dried blood spots (DBS) obtained on collection cards to be used as a tool for targeted screening for hypogammaglobulinemia. METHODS: DBS samples, along with simultaneous serum samples, were collected from 107 healthy individuals (11 months to 57 years of age). After eluting proteins from DBS, IgG, IgM, and IgA were quantified by an enzyme-linked immunosorbent assay (ELISA). The Ig-DBS assay was validated through calibration curve performance, intra- and inter-assay precision, accuracy, specificity, selectivity, and linearity. The ELISA measurements were compared with serum Ig levels obtained using a standard nephelometry assay on serum samples collected simultaneously with the DBS samples and the results of the two assays were correlated. The stability of IgG, IgM, and IgA in the DBS was tested at room temperature, 36° to 38 °C, 2 to 8 °C, and −25 to −40 °C, from 4 to 14 days. RESULTS: The Ig-DBS assay demonstrated precision, accuracy, specificity, selectivity, and linearity. Using the identified correlation coefficients of 0.834 for IgG, 0.789 for IgM, and 0.918 for IgA, the standard nephelometry-based normal reference ranges for all 3 serum Ig isotypes could be used with the Ig-DBS assay in individuals ≥16 years of age. The DBS samples were stable for 14 days at room temperature in a closed polyethylene bag. CONCLUSIONS: The Ig-DBS assay is both sensitive and accurate for quantification of serum immunoglobulins. Samples are sufficiently stable at ambient temperature to allow for convenient shipping and analysis at a centralized laboratory. This assay therefore presents a new option for screening patients ≥16 years of age for hypogammaglobulinemia in any setting