title: Disorder-specific changes in innervation in oral lichen planus and lichenoid reactions.
abstract: The peripheral nervous system was analysed in the oral mucosa of eight patients with oral lichen planus (OLP), five with a lichenoid reaction (LR) and three with mild chronic inflammation (MCI), by morphometric analysis of nerve fibres containing immunoreactive PGP 9.5, substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), or C-flanking peptide of neuropeptide Y (CPON). Overall nerve fibre density was higher in OLP (P=0.039) and LR (P=0.026) compared with healthy oral mucosa and was compatible with sprouting and collateral formation. In contrast to the innervation visualized with structural nerve fibre-marker PGP 9.5, the densities of neuropeptide-immunoreactive nerves were low in inflamed tissue. This is consistent with depletion via local release. Retraction and local loss of innervation were found in areas coinciding with the most severe inflammation and basal membrane (BM) damage. Interestingly, LR showed a twenty-eight-fold loss of post-ganglionic CPON-ir sympathetic nerve fibres (P=0.044). In LR, CPON-ir innervation was markedly lower than in OLP. Finally, the pattern of innervation in relation to inflammatory cell infiltrates and tissue structures differed between OLP and LR. In conclusion, the peripheral nervous system is implicated in the immunopathogenesis of lichen planus and lichenoid reactions, with a disorder-specific difference in this involvement.
authors.affiliation: Department of Oral Medicine, Institute of Dentistry, University of Helsinki, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Nissalo
authors.forename: J
authors.initials: J
authors.lastname: Hietanen
authors.forename: M
authors.initials: M
authors.lastname: Malmström
authors.forename: M
authors.initials: M
authors.lastname: Hukkanen
authors.forename: J
authors.initials: J
authors.lastname: Polak
authors.forename: Y T
authors.initials: YT
authors.lastname: Konttinen
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001485:Basement Membrane / Q000473:pathology; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D002908:Chronic Disease; D006801:Humans; D017676:Lichen Planus, Oral / Q000473:pathology*; D017512:Lichenoid Eruptions / Q000473:pathology*; D008875:Middle Aged; D009059:Mouth Diseases / Q000473:pathology*; D009061:Mouth Mucosa / Q000294:innervation*; D009412:Nerve Fibers / Q000473:pathology*; D009419:Nerve Tissue Proteins / Q000032:analysis; D009478:Neuropeptide Y / Q000032:analysis; D018709:Statistics, Nonparametric; D013280:Stomatitis / Q000473:pathology; D013373:Substance P / Q000032:analysis; D013564:Sympathetic Nervous System / Q000473:pathology; D013869:Thiolester Hydrolases / Q000032:analysis; D043222:Ubiquitin Thiolesterase; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
chemical_list: D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013869:Thiolester Hydrolases; D043222:Ubiquitin Thiolesterase; D015740:Calcitonin Gene-Related Peptide