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Interpretive Handbook

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Test 83680 :
Desmoglein 1 (DSG1) and Desmoglein 3 (DSG3), Serum

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Pemphigus includes a group of often fatal autoimmune, blistering diseases characterized by intraepithelial lesions. Pemphigus vulgaris and its variants may present with oral or mucosal lesions alone or with mucosal plus skin lesions. Pemphigus foliaceous and variants present with skin lesions alone.

 

Indirect immunofluorescence (IIF) studies reveal that both forms of pemphigus are caused by autoantibodies to cell surface antigens of stratified epithelia or mucous membranes and skin. These antibodies bind to calcium-dependent adhesion molecules in cell surface desmosomes, notably desmoglein 1 (DSG1) in pemphigus foliaceus and desmoglein 3 (DSG3) and/or DSG1 in pemphigus vulgaris. Desmogleins are protein substances located in and on the surface of keratinocytes. These proteins have been shown to be a critical factor in cell-to-cell adhesion. Antibodies to desmogleins can result in loss of cell adhesion, the primary cause of blister formation in pemphigus.

 

The diagnosis of pemphigus depends on biopsy and serum studies that characterize lesions and detect the autoantibodies that cause them. Originally, the serum studies were performed by IIF using monkey esophagus and other tissue substrates. The identification of the reactive antigens as DSG1 and DSG3 has made it possible to develop highly specific and sensitive enzyme-linked immunosorbent assay methods.

Useful For Suggests clinical disorders or settings where the test may be helpful

Preferred screening test for patients suspected to have an autoimmune blistering disorder of the skin or mucous membranes (pemphigus)

 

As an aid in the diagnosis of pemphigus

 

Monitoring treatment response in patients with a confirmed diagnosis of pemphigus

Interpretation Provides information to assist in interpretation of the test results

Antibodies to desmoglein 1 (DSG1) and desmoglein 3 (DSG3) have been shown to be present in patients with pemphigus. Many patients with pemphigus foliaceus, a superficial form of pemphigus have antibodies to DSG1. Patients with pemphigus vulgaris, a deeper form of pemphigus, have antibodies to DSG3 and sometimes DSG1 as well.

 

Antibody titer correlates in a semiquantitative manner with disease activity in many patients. Patients with severe disease can usually be expected to have high titers of antibodies to DSG. Titers are expected to decrease with clinical improvement.

 

Our experience demonstrates a very good correlation between DSG1 and DSG3 results and the presence of pemphigus. Adequate sensitivities and specificity for disease are documented. However, in those patients strongly suspected to have pemphigus either by clinical findings or by routine biopsy, and in whom the DSG assay is negative, the IIF test (CIFS / Cutaneous Immunofluorescence Antibodies [IgG], Serum) is recommended.

 

For further information, see Cutaneous Immunofluorecence Testing in Special Instructions.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Recommend repeat testing of indeterminate specimens, either with a fresh specimen drawn at a later time or the original specimen tested by another method.

 

The desmoglein 1 (DSG1) and desmoglein 3 (DSG3) results serve only as an aid to diagnosis and should not be interpreted as diagnostic by themselves. The results should be interpreted in conjunction with clinical evaluation of the patient along with other diagnostic procedures.

 

Performance of these assays in the pediatric population has not been established.

 

The assay performance characteristics have not been established for matrices other than serum.

 

A positive result indicates the presence of antibodies to recombinant DSG1 and DSG3 and does not specifically identify a certain type of pemphigus.

 

A negative result does not rule out the presence of pemphigus.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

DESMOGLEIN 1

<14.0 U (negative)

14.0-20.0 U (indeterminate)

>20.0 U (positive)

 

DESMOGLEIN 3

<9.0 U (negative)

9.0-20.0 U (indeterminate)

>20.0 U (positive)

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Amagai M, Tsunoda K, Zillikens D, et al: The clinical phenotype of pemphigus is defined by the anti-desmoglein autoantibody profile. J Am Dermatol 1999 Feb;40(2 Pt 1):167-170

2. Amagai M, Komai A, Hashimoto T, et al: Usefulness of enzyme linked immunoabsorbent assay using recombinant desmogleins 1 and 3 for sero-diagnosis of pemphigus. Brit J Dermatol 1999 Feb;140(2):351-357

3. Harman KE, Gratin MJ, Bhogal SJ, et al: The clinical significance of autoantibodies to desmoglein 1 in 78 cases of pemphigus vulgaris. J Invest Derm 1999;115:568


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