Immunohisto- and cytochemical examinations in labial salivary glands from Sjögren's syndrome patients with sensory neuropathy

Background and aim: A predominance of sensory neuropathy was earlier described in Sjögren's syndrome (SS), which might precede the presence of sicca symptoms. The mechanism of sensory neuropathy in SS is unknown. Therefore aim of this study was to determine the quantitative changes of the different neuropeptide containing nerve terminals and the immunocompetent cells in labial salivary glands of primary SS.

Methods: Immunohisto- and cytochemical methods were used for the detection of immunoreactive (IR) elements and the data were compared with the healthy controls.

Results: All of the investigated IR nerve fibres were found in different quantity and localization in both of control and SS glands. The density of them was changed variously in SS. The number of the substance P (SP), neuropeptide Y (NPY) (p<0.05), galanin (GAL) IR nerve terminals was decreased, however the number of vasoactive intestinal polypeptide (VIP) and tyrosine β-hydroxylase (TH) IR nerve fibres (p<0.05) was increased compared to the control. No Poly (ADP-ribose) polymerase activation was detected in SS. There were no IR immunocompetent cells in the control materials, however, a large number of them showed IR for SP and NPY in the SS.

Conclusion: These neuropeptides might have a role in the sensory neuropathy; they might activate nociceptive and sympathetic pathways. Some neuropeptides (SP, NPY) are endogenous in the immunosystem and produced in certain conditions e.g. inflammation and chronic autoimmune disorders such as SS, so they might participate in the neuro-immunomodulation and contribute to the atrophy, apoptosis and necrosis.