Effect of Bifidobacterium Animalis Subsp. Lactis HN019 on Oral Lichen Planus

This is a randomized double-blind clinical trial with symptomatic patients presenting OLP, which will be randomly assigned to either topical Bifidobacterium animalis subsp lactis HN019 or clobetasol propionate 0.05%. The selected patients will receive capsules to be diluted in 15 ml of water containing 6 x 109 CFUs of Bifidobacterium subsp. lactis HN019 (experimental group) or 0.05% clobetasol propionate (control group) for mouth washing, twice a day for 4 weeks. Patients will be instructed to maintain normal brushing and not to use or consume another corticosteroid and /or probiotic during the study. Outcomes measures will be symptoms (VAS and Likert-like scale), quality of life (SF-36 form), and clinical changes (erythema, reticulation, erosion/ulcer based on clinical photographs), which will be performed at baseline, 15 days (only VAS, Likert-like scale and photographs) and and at one month of treatment. All patients will undergo biopsies for the diagnosis of OLP, and those who consent will be submitted to an optional biopsy at the end of the topical treatment for histopathological and immunopathological characterization.

Inclusion criteria

• Clinical inclusion

• Adults ≥ 18 years old, both genres, who consent to participate of the study;
• Presence of symptomatic reticular lesion and/or white-gray papules. In afro-descendent individuals, reticular lesions may be associated with hyperpigmented lesions;
• Additional clinical features such as ulcerative, erythematous, plaque and bullous lesions will be accepted in the presence of bilateral and symmetrical reticular lesions.
• Histopathological inclusion criteria

• Presence of subepithelial infiltrate predominantly lymphocytic, in band and confined to the subepithelial area.
• Liquefaction degeneration of the basal cells layer.

Exclusion criteria

• Clinical exclusion criteria

• Exclusion of contact lichenoid lesions: the pattern of reticular lesion and / or papules should not be present only in areas of physical contact with restorative materials;
• Exclusion of lichenoid reaction to the drug: difficult to differentiate from OLP, however it is necessary to report all drugs in use by the patient; the comparison between patients on medication, and those who do not use medication is important to establish subgroups of OLP;
• Exclusion of chronic graft versus host disease (GVHD): differentiation between OLP and GVHD is established in most cases by medical history;
• Exclusion of immunocompromised patients or patients with systemic diseases of high complexity.
• Exclusion of patients who have previously used probiotic bacteria in the last 4 weeks prior to the study.
• Histopathological criteria for exclusion • Presence of epithelial dysplasia, absence of the lymphocytic inflammatory infiltrate band and liquefaction degeneration.