EDITORIAL: HEPATITIS C VIRUS AND LICHEN PLANUS: THE REAL ASSOCIATION

L planus (LP) is a common T-cell-mediated chronic inflammatory disease of the stratified squamous epithelium, with unknown etiology. It can affect oral mucosa, the skin, genitalia, hair follicles, nails, esophagus, urinary tract, nasal mucosa, larynx and even the eyes (1). Local conditions such as poor oral hygiene and smoking may increase the chance of the immune trigger by increasing the exposure. Oral LP (OLP) affects women more than men (1,2) and occurs predominantly in adulthood, although young people and children might be affected (1). Clinically, the OLP has six variants: Papular, reticular, plaque-like, atrophic, erosive and bullous. These features may occur individually or in combination (2). There is ongoing concern that OLP may be premalignant (3). While skin lesions occur in 20% of patients with OLP, cutaneous lesions are associated with oral lesions in 70%–77% of cases (4). The oral mucosa in OLP is highly accessible for an accurate examination. Therefore, OLP is ideal for the study of human T-cell-mediated inflammation and autoimmunity (5-7). Oral lesions are characteristically raised multiform white lesions, accompanied by areas of erosions and pigmentation (1). Histological features of the LP are nonspecific and there are no well-accepted criteria for its diagnosis (8) which makes its definite diagnosis difficult. Hepatitis C virus (HCV) is a single-stranded RNA virus which is recognized as a global concern (9). Worldwide, more than 170 million people are infected with HCV (10). The virus has an extremely variable genome, six distinct genotypes and multiple subtypes (5). It is estimated that 0.16% of the Iranian general population are infected with the virus (11). Infection with HCV has been found to be a major cause of liver diseases. Although the incidence of HCV infection is significantly lower than that of hepatitis B virus (HBV) infection, the rate of chronically infected individuals is much higher (12). Morbidity associated with HCV infection is not only due to the sequelae of chronic liver disease, but is also due to a variety of extrahepatic manifestations (5). There is no efficient vaccine available and it seems too optimistic to predict one in the near future. More epidemiologic studies are needed to better assess the epidemiological characteristic of the disease (13). Correlation between HCV infection and some oral diseases such as OLP, Sjogren’s syndrome, and sialadenitis has been reported. Moreover, OLP was found associated with a number of viral infections including Epstein-Barr virus, cytomegalovirus, varicella zoster virus, human herpes virus , human papilloma virus, and human immunodeficiency virus (HIV). However, the most frequent evidence relates to HCV infection (14, 15).