Programmed cell removal biomarkers calreticulin and CD47 implicated in oral lichen planus

Objectives: To investigate the expression of the programmed cell removal markers, calreticulin (CRT) and CD47, known to be involved in various autoimmune diseases, in patients with oral lichen planus (OLP), and to investigate the association with clinical behavior. Materials and methods: Biopsies of 78 patients with OLP were included. The clinical data were collected from patients' charts. The expression of CRT and CD47 was immunomorphometrically analyzed in the epithelial (CRTep, CD47ep) and inflammatory cells (CRTinf, CD47inf), and the results were correlated with the clinical presentation. Results: The epithelial and inflammatory cells expressed CRT (2.83 ± 6.62 and 5.13 ± 3.72) and CD47 (7.92 ± 4.6 and 10.7 ± 7.16). The expressions of CD47ep and CD47inf were associated (R = 0.64, P < 0.0005) with one another. The expressions of CRTinf and CD47ep were higher in atrophic erosive forms (A/ELP) than in the keratotic form of patients with OLP (6.46 ± 0.76 and 9.38 ± 0.87 vs 4.2 ± 0.61 and 6.84 ± 0.91, respectively, P = 0.002 and P = 0.021). The expression of CRTep was associated with more localized lesions (P < 0.009) and more abundant in males (P = 0.049), and the expression of CRTinf was associated with the presence of skin lesions and symptoms (P < 0.034 and P = 0.047, respectively). Only in A/ELP patients, the expression of CRTep was associated with high expression of CD47ep (R = 0.6, P = 0.004), where both CD47ep and CD47inf were associated with lower age of the patients (R = -0.48, P = 0.03 and R = -0.54, P = 0.01). Conclusions: The pattern of expression of CRT and CD47 in OLP suggests a general programmed cell removal response in OLP. Symptomatic patients may benefit from CRT/CD47 targeted therapy in the future.