Human serum substitution by artificial sera of scalable allergen reactivity based on polyclonal antibodies and chimeras of human FcγRI and IgE domains.

Human sera are the first choice as controls for diagnostic applications such as immunoassays, but are limited regarding availability, varying quality, and high costs. In this study, we aimed to circumvent these limitations by the use of a chimeric adaptor molecule comprising the extracellular domains of the human FcγRI (CD64) fused with human IgE Fc domains (CD64-IgE Fc). Allergen-specific antibodies were produced in rabbits using eight different allergens, extracts, and allergen mixtures including mites, pollen, drugs, and food. Preincubation of polyclonal IgG with CD64-IgE Fc established allergen-specific artificial sera that showed comparable results for more than 20 allergens and allergen extracts in three diagnostic systems for the determination of specific IgE. The agreement for these artificial sera is within ±1 radioallergosorbent test (RAST) class. Hence, rabbit IgG complexed with the IgG-specific CD64-IgE Fc adaptor molecule could provide a substitute for human reference sera with specificity for virtually any protein of interest.

Evaluation of a Novel Rapid Test System for the Detection of Allergic Sensitization to Timothy Grass Pollen against Established Laboratory Methods and Skin Prick Test.

Type I hypersensitivity is driven by allergen specific immunoglobulin E (sIgE) and thus sIgE represents a marker for modern allergy diagnosis. Recently, a rapid assay for the detection of sIgE, termed as (Allergy Lateral Flow Assay) ALFA, has been developed. The objective of our study is the evaluation of a scanner-based system for the semiquantitative interpretation of ALFA results. Agreement to Skin Prick Test (SPT, Allergopharma), ALLERG-O-LIQ System (Dr. Fooke), and ImmunoCAP (Phadia) was investigated using 50 sera tested for specific IgE to timothy grass pollen (g6). 35/50 sera were positive by SPT, ALLERG-O-LIQ, and ImmunoCAP. Excellent agreement was observed between ALFA results and SPT, ImmunoCAP, and ALLERG-O-LIQ. Area under the curve (AUC) values were found at 1.0, and 100% sensitivity and specificity was found versus all other methods. Visual- and scanner-based interpretation of the ALFA results revealed excellent agreement.

IgM/IgA nephropathy in callitrichids: antigen studies.

Renal tissues of callitrichids with IgM nephropathy were immunohistochemically examined for the participation of IgA in pathogenesis. In 58 histopathologically nephropathy-positive kidneys, IgM predominated in 20 cases and IgA in 7 cases, and in 31 cases both immunoglobulins were rated to be approximately equally involved. The disease, therefore, might be described as IgM/IgA nephropathy. The renal tissues and sera were also tested for nutritional antigens or antinutritional antigen antibodies, using immunohistochemistry and Western blots (tissues) and enzyme-linked immunosorbent assay (sera). Evidences of nutritional antigens in the renal tissues were inconclusive, although circulating IgG class antibodies against cereals, milk, and egg proteins were present in quite a number of sera. Particular consideration was paid to IgA-antigliadin antibodies, which were statistically significantly associated with nephropathy as were IgA rheumatoid factors. The findings are discussed in relation to human IgA and IgM nephropathies.