Duplication in CHIT1 Gene and the Risk for Aspergillus Lung Disease in CF Patients

Title: Duplication in Chitotriosidase (CHIT1) Gene and the Risk for Aspergillus Lung Disease in CF Patients.

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).

Aim: to evaluate the link between CHIT1 duplication in CF patients and the predisposition to ABPA or persistent Aspergillus infection.

Patients: 40 CF patients divided to three groups .Group 1: patients who have neither ABPA nor Aspergillus infection in the past (the control group).Group 2: patients with persistent Aspergillus infection, without ABPA. Group 3: patients with current or past ABPA.

Design: Observational, single visit. Methods: All patients will be assessed for pulmonary function tests (PFT), sputum cultures, and blood tests for: CHIT1 duplication, IgE and Eosinophils levels.

Patient's characteristics including demographics, CF mutations, pancreatic status and sweat test will be derived from the charts.

Patients with ABPA as well as Aspergillus infection had also radioallergosorbent test (RAST) for molds, as well as skin prick test for Aspergillus and blood Galactomannan.

The primary outcome measure is the difference in CHIT1 genotyping between the groups.

Inclusion criteria

• Confirmed diagnosis of Cystic Fibrosis.

Exclusion criteria

• Inability to produce sputum, or previous history of lung transplantation.