Article

Improved multiplex immunoassay performance in human plasma and synovial fluid following removal of interfering heterophilic antibodies

Utrecht University, Utrecht, Utrecht, Netherlands
Journal of Immunological Methods (Impact Factor: 2.01). 06/2005; 300(1-2):124-35. DOI: 10.1016/j.jim.2005.03.009
Source: PubMed

ABSTRACT Cytokines, chemokines and soluble adhesion molecules interact in a complex network within the immune system. Fingerprinting of these proteins may allow the use of these proteins as biomarkers for identification of disease, disease subtyping and monitoring therapeutic interventions. We developed a multiplex immunoassay (MIA) for the detection of 30 proteins in a variety of human body fluids such as plasma and synovial fluid (SF). The measurement of these proteins is hampered by the presence of human (auto-) antibodies, which can cause non-specific binding. We have validated a novel approach for the removal of interfering immunoglobulins using pre-absorption with protein-L. Interfering (auto-) antibodies, such as rheumatoid factor (RF), were removed using three methods; polyethylene glycol (PEG) precipitation, pre-absorption with human gamma-globulin or pre-absorption with protein-L. A significant decrease of RF was observed after a 2 h incubation with protein-L. RF IgM levels were reduced by 89% whereas total IgM, IgG and IgA levels were reduced by 60%. Residual immunoglobulins were blocked with rodent serum and did not interfere with the multiplex immunoassay. Comparing the MIA with a conventional enzyme-linked immunosorbent assay (ELISA) using a panel of spiked plasma samples resulted in correlation coefficients for all mediators between R2 = 0.88 and R2 = 0.99. Intra-assay variance was less than 10% whereas inter-assay variance ranged between 6% and 16%. Pathological samples with heterophilic antibodies hamper immunoassays such as ELISA and MIA. We show that pre-absorption with protein-L is a powerful tool for removal of interfering immunoglobulins from human bodily fluids to be used in immunoassays for studying changes in protein patterns.

Download full-text

Full-text

Available from: Wilco de Jager, Oct 23, 2014
2 Followers
 · 
234 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are chronic diseases characterized by activation of the immune system and production of antibodies. Thus, rheumatoid factor, anti-animal IgG antibodies and heterophilic antibodies in plasma samples from arthritis patients can interfere with immunoassays such as sandwich enzyme-linked immunosorbent assay (ELISA) systems often used in arthritis research. However, standard methodologies on how to test for false results caused by these antibodies are lacking. The objective of this study was to design a simple set of steps to validate a sandwich ELISA before using it for measuring analytes in plasma from arthritis patients. An interleukin-24 (IL-24) sandwich ELISA system was prepared with a monoclonal mouse capture antibody and a polyclonal goat detection antibody and tested for interference by rheumatoid factor, anti-animal IgG antibodies and heterophilic antibodies. Plasma samples from 23 patients with RA and SpA were used. No differences were found between plasma samples measured in wells coated with anti-IL-24 specific antibody and in wells coated with isotype control antibody (false positive results), and recombinant human IL-24 was not recovered in spiked samples (false negative results). This interference was removed after preincubating the plasma samples from patients with arthritis with goat or bovine IgG, suggesting that anti-animal IgG antibodies found in the plasma of the arthritis patients caused the false results. Additional testing showed that the signal-to-noise ratio could be increased by titration of the capture and detection antibodies and by using the ELAST amplification system. Finally, the calculated concentration of IL-24 was increased in ethylenediaminetetraacetic acid (EDTA) plasma compared to heparin plasma and serum and decreased with repetitive freeze/thaw cycles of the samples illustrating how sample handling could additionally contribute to the variations reported by different laboratories in measurement of the same analyte. This study proposes a simple set of validation steps to evaluate and optimize a sandwich ELISA before using it for measuring analytes in plasma from arthritis patients. Anti-animal IgG antibodies are also present in healthy individuals, suggesting that validation of ELISA systems for measuring non-arthritis samples could also be improved by this simple set of validation steps.
    SpringerPlus 12/2013; 2(1):263. DOI:10.1186/2193-1801-2-263
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To develop a method of the assay of chemokine and cytokine signaling in synovial fluid from patients suffering from osteoarthritis (OA) or rheumatoid arthritis (RA) and evaluate the effect of heterophilic antibodies on the reliability of the data. 21 synovial fluid samples from OA and 16 synovial fluid samples from RA patients were analyzed using a unique 2 step dot sandwich ELISA based micro-well protein array designed to detect heterophilic antibody signaling in the presence or absence of an effective heterophilic blocking reagent with assays carried out for Eotaxin, hGROa, Interleukin (IL)-8, IP10, MCP-1, MCP-2, MIG, RANTES, TARC and IL-6. Array analysis reveals that the selective presence of heterophilic antibodies interferes with the accurate assay of synovial fluid samples from a minority of RA patients but not OA synovia. Using a commercial blocking diluent OA and RA synovial fluids reveal significant differences in chemokine content (IL-6, Eotaxin, hGROa, MCP-2, MIG, TARC, IL-8, RANTES). Using a two-step assay protocol it is possible to readily detect inappropriate antibody signaling due to heterophilic antibodies and devise a protocol designed to eliminate this problem thereby more accurately quantify cytokines and chemokines specific to both RA and OA fluids.
    Journal of immunological methods 08/2013; DOI:10.1016/j.jim.2013.08.007 · 2.01 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Heat shock protein 60 (hsp60) is a highly conserved stress protein and target of self-reactive T cells in various inflammatory diseases. Not much is known about a possible role in atopic disease. As atopic diseases are considered to be the result of a disturbance in the balance between T helper cells type 2 and regulatory T cells, it is of interest to know whether hsp60 acts as a bystander antigen in atopic disease. Our aim was to investigate whether hsp60 is involved in the chronicity of inflammation of atopic dermatitis (AD). We studied the expression of hsp60 in skin tissue of adults with AD by immunohistochemistry. Peripheral blood mononuclear cells (PBMC) of children with AD were cultured with hsp60 and proliferative responses, cytokine secretion, surface markers, and functional assays were compared to responses of PBMC of healthy controls (HC). Hsp60 was detected more in lesional skin of AD patients compared to nonlesional skin. Furthermore, PBMC of children with AD proliferated more strongly in response to hsp60 compared to HC. hsp60-reactive T cells of atopic children produced high levels of IFNγ and low levels of IL-10. In vitro activation with hsp60 leads to the induction of CD4(+)CD25(bright) T cells expressing FOXP3 in both HC as well as in atopic children. However, despite their regulatory phenotype, hsp60-induced CD4(+)CD25(bright)CD127(-)FOXP3(+) T cells of AD patients were incapable of suppressing effector T cells in vitro. hsp60 is recognized by proinflammatory (IFNγ high, IL-10 low) T cells in atopic patients and is more present in lesional AD skin. This suggests that hsp60-specific T cell responses contribute to local inflammation in AD.
    Cell Stress and Chaperones 08/2012; 18(1). DOI:10.1007/s12192-012-0361-3 · 2.54 Impact Factor