Histopathological parameters of the main lachrymal gland from patients with primary Sjögren's syndrome (SS1) were investigated, and the relation between morphological and immunohistochemical changes in the innervation of lachrymal gland in patients with SS1, as well as the immunopathological differences between SS1, non-autoimmune keratoconjunctivitis sicca (KCS) and controls were analysed.
Lachrymal glands from patients with SS1, KCS and control subjects were biopsied and examined using standard transmission electron microscopic techniques and an immunohistochemical method (vasoactive intestinal polypeptide-VIP).
Moderate numbers of myelinated and non-myelinated nerve fibres were found in the connective tissue around lachrymal glands in patients with SS1. Non-myelinated nerve fibres made contact with glandular epithelium, myoepithelial cells, vascular endothelium, plasma cells and fibroblasts. Patients with non-immunological KCS had similar characteristics as SS1 in number and activity, showing a normal morphological pattern. Control subjects showed a higher number of active nerve fibres.
Main lachrymal gland from patients with SS1 were therefore definitively innervated with moderate activity and normal structures. The ultrastructural study demonstrated there were no statistical differences with respect to patients with non-autoimmune KCS. Immunohistochemical studies showed a similar VIP activity in lachrymal gland between patients with SS1 and KCS, but there was a significant decrease in the innervation activity with regard to control subjects. All this implies that the autoimmunological factor in patients with SS1 does not significantly affect the lachrymal gland innervation.