ABSTRACT
Reference intervals were estimated for immunoglobulins IgA, IgG and IgM in serum in 313 healthy adults aged 17 to 64 years and in 399 children aged 6 months to 14 years. In adults a nonparametric method was chosen for estimating reference interval limits. In children the limits were estimated age-specifically using regression analysis. Immunoglobulin assays used in this study were standardized with a Finnish secondary standard which was calibrated against the World Health Organisation 67/99 immunoglobulin standard. Later, another international primary standard (US National protein standard preparation) was used, the immunoglobulin levels of which are calibrated against the WHO standard. The nominal immunoglobulin concentrations assigned by the manufacturers of several commercial immunoglobulin standard preparations were found to differ from the concentrations measured with the international calibrator used in this study. In conclusion, the reference intervals estimated in this study should be transferable to any laboratory using immunoglobulin assays calibrated against the WHO standard. The usefulness of commercial immunoglobulin standard preparations not calibrated against these primary standards is limited.
Subject(s)
Immunoglobulin A/metabolism , Immunoglobulin G/metabolism , Immunoglobulin M/metabolism , Adolescent , Adult , Age Factors , Child , Child, Preschool , Female , Humans , Immunoglobulin A/standards , Immunoglobulin G/standards , Immunoglobulin M/standards , Infant , Male , Middle Aged , Reference Standards , Reference Values , Regression Analysis , Sex FactorsABSTRACT
A very sensitive solid-phase fluorescent immunoassay to detect anti-alpha-gliadin IgA class antibodies is described. The solid phase consisted of polystyrene carboxylated microspheres, of 5 microns diameter, coated with alpha-gliadin. Serum-specific antibodies bound to the alpha-gliadin were measured by flow cytometry using fluorescein-conjugated anti-human IgA. 41 samples were tested and the results compared with those obtained by a standard method: an enzyme-linked immunosorbent assay (ELISA). A good correlation was found between the two techniques (r = 0.96). The sera of untreated coeliac children showed significantly higher antibody values than the sera of children on a gluten-free diet or healthy control groups. The flow cytometric method was more sensitive when the Kolgomorov/Smirnov test was used to analyse the histograms. This method provides an alternative screening test for coeliac disease and may also be used to confirm borderline results obtained in the ELISA test.
Subject(s)
Flow Cytometry , Gliadin/immunology , Immunoglobulin A/analysis , Plant Proteins/immunology , Celiac Disease/diagnosis , Child , Enzyme-Linked Immunosorbent Assay , Flow Cytometry/methods , Flow Cytometry/standards , Fluorescent Antibody Technique/standards , Humans , Immune Sera/analysis , Immunoglobulin A/standards , Microspheres , Reference Standards , Reference ValuesABSTRACT
We have developed sensitive enzyme-linked immunosorbent assays (ELISA) which measure mouse serum heavy chain immunoglobulin isotypes in nanograms per milliliter. In each case the specific isotypic Ig is sandwiched between an isotype-specific antibody used for coating and another isotype-specific antibody coupled to biotin for detection (with alkaline phosphatase coupled to avidin). These methods are simple to perform, specific for each isotype, reproducible with an average coefficient of variation of 5% for IgG1, 3% for IgG2a, 7% for IgG2b, 10% for IgG3, 3% for IgA and 7% for IgM, and at least 100 times more sensitive than radial immunodiffusion. The assays have been used to determine the absolute concentrations of mouse serum heavy chain Ig isotypes.
Subject(s)
Antibody Specificity , Enzyme-Linked Immunosorbent Assay , Immunoglobulin Isotypes/analysis , Animals , Enzyme-Linked Immunosorbent Assay/standards , Female , Immune Sera/analysis , Immune Sera/standards , Immunoglobulin A/analysis , Immunoglobulin A/standards , Immunoglobulin G/analysis , Immunoglobulin G/standards , Immunoglobulin Heavy Chains/analysis , Immunoglobulin Isotypes/classification , Immunoglobulin Isotypes/standards , Immunoglobulin M/analysis , Immunoglobulin M/standards , Mice , Mice, Inbred C57BL , Rats , Reference Standards , Reproducibility of ResultsABSTRACT
Quality criteria for i.v.-immunoglobulins (i.v.- Igs) are critically discussed laying emphasis on spontaneous anticomplementary activity (aca) and size-dependent composition. Considering the percentage of fractions obtained by gel filtration (Ultrogel AcA 34), however, the monomeric IgG containing fraction contributed the major part of aca under the experimental conditions chosen. Subclass IgG3 seems to contribute considerably to aca. No correlation was found between aca and the percentage of fractions containing components larger in size than IgG dimers in various commercially available Igs. Moreover, the subclass distribution in different batches of individual products showed considerable variations. The amount of IgG4 is correlated with that of IgA in chemically unmodified products relatively poor in IgA (approx. less than or or equal to 10 mg/5 g Ig), indicating that attempts to reduce IgA consequently result in removal of IgG4.
Subject(s)
Complement C3/immunology , Immunoglobulins/standards , Complement System Proteins/immunology , Humans , Immunodiffusion/methods , Immunoglobulin A/standards , Immunoglobulin G/immunology , Immunoglobulin G/standards , Immunoglobulins/administration & dosage , Injections, Intravenous , Macromolecular Substances , Nephelometry and Turbidimetry/methods , Quality ControlABSTRACT
An Australian Reference Preparation of human serum immunoglobulins was prepared from pooled sera of 240 healthy, adult donors. The preparation was calibrated for IgG, IgA and IgM levels by radial immunodiffusion against the 1st International Reference Preparation of Human Serum Immunoglobulins G, A and M (IgG, IgA and IgM) and for IgE by PRIST against the 1st International Reference Preparation of Human Serum Immunoglobulin E (IgE). The following potency values were assigned to the Australian Reference Preparation designated ASPS 78-1 (Lyoph.): 100 IU/vial for IgG and IgE, 102 IU/vial for IgA and 114 IU/vial for IgM.
Subject(s)
Immunoglobulin A/standards , Immunoglobulin E/standards , Immunoglobulin G/standards , Immunoglobulin M/standards , Reference Standards , Australia , HumansABSTRACT
By quantitative immunodiffusion tests, nasal secretion immunoglobulin A was underestimated by approximately 5.6-fold when the serum 7S immunoglobulin A standard was employed.
Subject(s)
Immunoglobulin A/analysis , Mucus/immunology , Nasal Mucosa/metabolism , Immunodiffusion , Immunoglobulin A/standardsSubject(s)
Immunoglobulins/analysis , Myotonic Dystrophy/immunology , Adolescent , Adult , Female , Humans , Immunoglobulin A/analysis , Immunoglobulin A/standards , Immunoglobulin G/analysis , Immunoglobulin G/standards , Immunoglobulin M/analysis , Immunoglobulin M/standards , Male , Middle Aged , Myotonic Dystrophy/bloodSubject(s)
Immunoglobulin A/standards , Adult , Age Factors , Aged , Female , Humans , Immunodiffusion , Male , Middle Aged , Sex FactorsABSTRACT
An International Reference Preparation for Human Serum Immunoglobulins G, A, and M has been established by the World Health Organization and international units have been assigned to it. This paper describes international collaborative assays carried out by 10 specialized laboratories, which attempted to define the immunoglobulin contents of the International Reference Preparation by weight. For all immunoglobulins the estimates of contents by weight were imprecise, largely owing to heterogeneity of estimates between laboratories. Mean estimates of immunoglobulin contents by weight are given, but it is considered that the results of assays of immunoglobulin against the International Reference Preparation or related preparations are more precisely expressed in terms of international units.
