Introduction: Chitinases are the enzymes that digest the chitin polymer. Plants use CHIT1 as an important innate defense mechanism against fungi. CHIT1 is the major chitinase in the human airways.Variation in the coding region, with 24-bp duplication allele results in a reduced CHIT1 activity. Recently, CHIT1 duplication was found in 6/6 patients with severe asthma and fungal sensitization Aspergillus often persists in the respiratory tract of patients with Cystic Fibrosis (CF) and may cause allergic broncho pulmonary aspergillosis (ABPA).