Sorted By Test Name - Mayo Medical Laboratories

CVID
87993
testing often depend upon the age of the patient, history of allergen exposure, season of the year, and
clinical manifestations. In individuals predisposed to develop allergic disease(s), the sequence of
sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and
bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat
proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to
sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).
Useful For: Testing for IgE antibodies may be useful to establish the diagnosis of an allergic disease
and to define the allergens responsible for eliciting signs and symptoms. Testing also may be useful to
identify allergens which may be responsible for allergic disease and/or anaphylactic episode, to confirm
sensitization to particular allergens prior to beginning immunotherapy, and to investigate the specificity of
allergic reactions to insect venom allergens, drugs, or chemical allergens.
Interpretation: Detection of IgE antibodies in serum (Class 1 or greater) indicates an increased
likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be
responsible for eliciting signs and symptoms. The level of IgE antibodies in serum varies directly with the
concentration of IgE antibodies expressed as a class score or kU/L.
Reference Values:
Class IgE kU/L Interpretation
0 Negative
1 0.35-0.69 Equivocal
2 0.70-3.49 Positive
3 3.50-17.4 Positive
4 17.5-49.9 Strongly positive
5 50.0-99.9 Strongly positive
6 > or =100 Strongly positive Reference values
apply to all ages.
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by
Laboratory Methods. 21st edition. Edited by RA McPherson, MR Pincus. New York, WB Saunders
Company, 2007, Chapter 53, Part VI, pp 961-971
Common Variable Immunodeficiency Confirmation Flow Panel
Clinical Information: The etiology of common variable immunodeficiency (CVID) is heterogeneous,
but recently 4 genetic defects were described that are associated with the CVID phenotype. Specific
mutations, all of which are expressed on B cells, have been implicated in the pathogenesis of CVID.
These mutations encode for: -ICOS: inducible costimulator expressed on activated T cells(2) -TACI:
transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor(3) -CD19(4)
-BAFF-R: B-cell activating factor belonging to the tumor necrosis factor (TNF) receptor family(5) Of
these, mutations of the gene that encodes TACI, TNFRSF13B (tumor necrosis factor receptor
superfamily, member 13B), probably account for about 10% to 15% of all CVID cases.(3) Patients with
mutations in the TACI gene are particularly prone to developing autoimmune disease, including
cytopenias, as well as lymphoproliferative disease. The other mutations each have been reported in only a
handful of patients. The etiopathogenesis is still undefined in more than 75% to 80% of CVID patients. A
BAFF-R defect should be suspected in patients with low to very low class switched and nonswitched
memory B cells and very high numbers of transitional B cells (see IABC/87994 B-Cell Phenotyping
Screen for Immunodeficiency and Immune Competence Assessment, Blood). Class switching is the
process that allows B cells, which possess IgD and IgM on their cell surface as a part of the
antigen-binding complex, to produce IgA, IgE, or IgG antibodies. A TACI defect is suspected in patients
with low IgA and low IgG with normal to low switched B cells, with autoimmune or lymphoproliferative
manifestations or both, and normal B cell responses to mitogens.
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