Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

JO1
80179
JOHN
82900
Jo 1 Antibodies, IgG, Serum
Clinical Information: Jo 1 (histidyl tRNA synthetase) is a member of the amino acyl-tRNA
synthetase family of enzymes found in all nucleated cells. Jo 1 antibodies in patients with polymyositis
bind to conformational epitopes of the enzyme protein and inhibit its catalytic activity in vitro.(1) Jo 1
antibodies are a marker for the disease polymyositis, and occur most commonly in myositis patients
who also have interstitial lung disease. The antibodies occur in up to 50% of patients with interstitial
pulmonary fibrosis and symmetrical polyarthritis.(2) See Connective Tissue Disease Cascade (CTDC)
in Special Instructions and Optimized Laboratory Testing for Connective Tissue Diseases in Primary
Care: The Mayo Connective Tissue Diseases Cascade in Publications.
Useful For: Evaluating patients with signs and symptoms compatible with a connective tissue
disease, especially those patients with muscle pain and limb weakness, concomitant pulmonary signs
and symptoms, Raynaudâ€s phenomenon, and arthritis
Interpretation: A positive result for Jo 1 antibodies is consistent with the diagnosis of polymyositis
and suggests an increased risk of pulmonary involvement with fibrosis in such patients.
Reference Values:
or =1.0 U (positive)
Reference values apply to all ages.
Clinical References: 1. Targoff I: Autoantibodies in polymyositis. Rheum Dis Clin North Am
1992;18:455 2. Leff R, Sherman J, Plotz P: Inflammatory muscle diseases. In Clinical Immunology
Principles and Practice, 2nd edition. Edited by R Rich, T Fleisher, W Shearer, B Kotzin, et al. St. Louis,
Mosby-Year Book, 2001, Chapter 65, pp 65.1-65.8
Johnson Grass, IgE
Clinical Information: Clinical manifestations of immediate hypersensitivity (allergic) diseases are
caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from
immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE
antibodies interact with allergen. In vitro serum testing for IgE antibodies provides an indication of the
immune response to allergen(s) that may be associated with allergic disease. The allergens chosen for
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
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