Salivary IgA and IgG antibodies to XXXX -NC16a as diagnostic biomarkers in Mucous Membrane Pemphigoid.

@entity1 @entity74 @entity5858 @entity7271
BACKGROUND: Mucous membrane pemphigoid (MMP) is an uncommon @entity74 predominantly affecting the oral mucosa and/or conjunctiva. In contrast to serum, the use of saliva for diagnosis of MMP by enzyme-linked immunosorbent assay (ELISA) using the non-collagenous domain (NC16a) of bullous pemphigoid antigen 2 ( @entity5858 ) has not been well described. OBJECTIVE: The aim of this study was to establish whether whole or parotid saliva might be a suitable alternative to serum for the diagnosis of MMP. METHODS: Commercially available pre-coated @entity5858 -NC16a ELISA plates were used to test serum, whole and parotid saliva for IgG, IgA and secretory IgA (SIgA) antibodies. Sixty-four MMP @entity1 provided matched serum, whole saliva and parotid saliva. Fifty healthy controls provided matched serum and whole saliva. An additional 6 healthy controls and 16 disease controls ( @entity7271 ( @entity7271 ) n=6, lichen planus (LP) n=10) provided matched serum, whole and parotid saliva. RESULTS: The criteria for a positive result was set at >2 SD above the mean of the levels measured in the healthy controls. In whole saliva, IgG antibodies were detected in 11/64 (17%) and IgA in 23/64 (36%) with a combined positivity 29/64 (45%). In parotid saliva IgA antibodies (which were also secretory component positive) were found in 8/18 (44%) patients. Serum IgG antibodies were detected in 27/64 (42%), serum IgA antibodies were detected in 18/64 (28%) with a combined positivity in 33/64 (52%). Control samples were all negative using these criteria yielding 100% positive predictive value for all the tests. The negative predictive values were 62% for IgA saliva, 65% for IgG serum, 59% for IgA serum and 56% for IgG saliva. CONCLUSIONS: IgG and IgA antibodies to NC16a may provide a suitable diagnostic marker in MMP. Assay of salivary IgA antibodies to NC16a offer a similar diagnostic predictive value to serum and may therefore be useful as a biomarker in the diagnosis and monitoring of MMP. This article is protected by copyright. All rights reserved.
