Montelukast treatment (cysteinyl leukotriene receptor antagonist) in a model of food allergy: modifications in lymphatic cell population from rectal mucosa.

OBJECTIVE The aim is to determine immunopathological modifications in rectal mucosa from rabbits after local challenge in ovalbumin (OVA) sensitized animals previously treated with montelukast. MATERIAL AND METHODS EXPERIMENTAL DESIGN thirty two rabbits divided into four groups: G1: normal; G2: subcutaneously OVA sensitized; G3: sensitized, locally OVA challenged and sampled 4 hours after challenge; and G4: sensitized, locally OVA challenged and treated 4 hours before challenge with montelukast (0.15 mg/kg). Specific anti-OVA IgE levels were evaluated by passive cutaneous anaphylaxis test (PCA). In each group 200 high microscopical power fields (HPF) were counted. Results were expressed as arithmetic mean and SE. Anti -CD4, CD5, micro chain monoclonal antibodies were used. Avidin biotin horseradish peroxidase system was used. RESULTS CD 4: G1: 8.3 +/- 0.06; G2: 13.4 +/- 0.08, G3: 8.25 +/- 0.06, G4: 11.8 +/- 0.02. CD 5: G1: 7.3 +/- 0.05; G2: 9.4 +/- 0.05, G3: 11.3 +/- 0.06, G4: 8.1 +/- 0.06. mu chain: G1: 10.4 +/- 0.06; G2: 3.8 +/- 0.02, G3: 6.0 +/- 0.10, G4: 2.2 +/- 0.10. In all cases, experimental groups (G3 vs. G4) presented statistical significant differences (p < 0.05). CD4+, CD5+ cells and mu chain+ decrease in experimental group (G4), probably due to lymphocyte migration inhibition to challenged mucosa. mu chain+ cell decrease could be based on B cell activation and expression of different surface immunoglobulins. Cells expressing mu chain decreased in G2 and G3 likely due to activation of B cells and subsequent expression of other immunoglobulin chains in cell surface. CONCLUSIONS We conclude that obtained data are important to elucidate immunopathology of local anaphylactic reaction in rectal mucosa from systemic sensitized animals after treatment with montelukast.