Practical usefulness of IgA-containing immune complex determination in the serum of patients with primary Sjögren's syndrome.
OBJECTIVE
To evaluate the relevance of IgA-containing immune complexes (IC) as a predictor of lymphocytic infiltration of the minor salivary glands, and thus to determine the necessity of the minor salivary gland biopsy as a diagnostic test for primary Sjögren's syndrome (SS) in patients complaining of dryness of the mouth.


METHODS
IgA-containing IC, as well as anti-SSA and anti-SSB antibodies, were measured using enzyme-linked immunosorbent assays in 116 consecutive patients presenting with dry mouth but no connective tissue disease. The specificity, sensitivity, and positive (PPV) and negative predictive values (NPV) of these tests were calculated in relation to the results of the minor salivary gland biopsy and to the criteria for primary SS.


RESULTS
Sixty-five patients had a focus score > or = 1.IgA-containing IC were detected in 45 of them, compared with five of the remainder (specificity 89%, sensitivity 69%, PPV = 88% and NPV = 69%). When the IgA-containing IC, and the anti-SSA and anti-SSB tests were associated, the sensitivity and NPV were improved (81 and 79%, respectively), while specificity and PPV were maintained (88 and 90%, respectively).


CONCLUSIONS
Given the reliability of this combination of tests for the diagnosis of primary SS, the minor salivary gland biopsy might be indicated only in those patients without any serological abnormality.
Basset
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Laboratory of Immunology, Brest University Medical School, France.
Pers
J O
JO
Youinou
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P
Pennec
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D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex / Q000097:blood* / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood; D001324:Autoantigens / Q000276:immunology; D001706:Biopsy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000276:immunology; D012469:Salivary Glands / Q000276:immunology / Q000473:pathology; D012680:Sensitivity and Specificity; D012859:Sjogren's Syndrome / Q000097:blood* / Q000276:immunology* / Q000473:pathology; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D000936:Antigen-Antibody Complex; D001323:Autoantibodies; D001324:Autoantigens; D007070:Immunoglobulin A; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human