Aim:The biological mechanism(s) that guide the immunological effectors of lymphocytes to sites of inflammatory response, a feature consistently seen in oral submucous fibrosis (OSF) was evaluated. It is envisaged that endothelial/lymphocyte adhesion cascades involving VCAM-1/α4β1 integrins control the migration of lymphocytes across the vascular endothelium resulting in their homing in these locales.Materials and Methods:The study group comprised 28 OSF cases (M:F = 12:16, age range 18-65 years; mean 55.4 ± 8.5 SD) divided into early (n=17) and advanced (n=11) disease groups. Biopsy specimens of normal buccal mucosa (site compatible) were obtained from 10 healthy volunteers (age and sex matched) who served as control. All the samples were fixed in 10% neutral-buffered formalin and embedded in paraffin. Immunolocalization of β1 subunit associated with α4 integrin was performed by a mouse heterodimer (clone 4B7R, Ig G, R & D Systems Inc., dilution 1:100) using a peroxidase labeled streptavidin–biotin technique. The immunocompetent cell density was expressed as the number of positive cells per mm2. The Mann–Whitney U-test and Fischer exact test were used to evaluate differences. P<0.05 was considered to be significant.Results:The median percentage of “T” lymphocytes with positive integrin α4β1 expression was 77.7 (an interquartile range of 73.3–83.4) for the test cases and for the controls, it was 28.2 (IQR 24.0–38.3). This difference was significant at 0.001 level. For the endothelial cells the positive expression was 82.8 (IQR 77–90.6) and 22.3 (IQR 18.3–29.2) respectively (P<0.001). When the intensity of integrin expression was considered 26/28 cases (96%) and 2/10 (20%) of controls showed intense expression of integrins α4β1 on T lymphocytes (P<0.001). Similarly, 27/28 cases (92.9%) and 2/10 (20%) of controls showed intense expression on endothelial cells (P<0.001). T lymphocyte–endothelial cell interactions were assessed by evaluating the overexpression of integrins on both the endothelial cells and lymphocytes together. The interaction was positive in 15/17 and 11/11 early and advanced OSF cases respectively (P=0.51).Conclusion:Following leukocyte activation, the interaction between leukocyte integrin heterodimers and endothelial superfamily adhesion ligands results in a firm adherence of leukocytes to endothelium, leading to leukocyte migration and homing to sites of mucosal inflammation consistently seen in OSF.

INTRODUCTIONTumours of salivary glands are rare constituting less than one percent of all tumours and 3% to 10% of the neoplasms of head and neck region.1,2 They are a heterogeneous group of tumours and present distinct clinicopathological features. Parotid gland accounts for 80% of salivary gland tumors followed by submandibular gland (10-15%).3 Majority of the primary tumours of salivary glands are benign but diagnosis of malignant tumours pose many difficulties in routine practice due to a wide spectrum of entities with overlapping in morphology.The histopathological features are intricate and differences between different types are very subtle and as such many challenges are encountered in establishing histological diagnosis, classification and grading of salivary gland neoplasms. The present work is taken up to study the incidence of salivary gland tumours in our ABSTRACT Background: Tumours of salivary glands are rare neoplasms of head and neck region accounting for less than one percent of all tumours. Parotid gland accounts for majority of tumors followed by submandibular gland. As such many challenges are encountered in establishing histological diagnosis, classification, grading and management of salivary gland neoplasms. This study is taken up to study the incidence of salivary gland tumours in our institution and analyse histological criteria for diagnosis and grading systems in vogue for common malignant lesions.