Background :

Cystic fibrosis (CF) patients are prone to recurrent pulmonary infection have different secreted mucin pattern from healthy subjects. Long chain polyunsaturated fatty acids have been shown to influence survival and MUC5B expression in mice model of chronic pulmonary infection.

Method :

To study the impact of LCPUFA n-3 on MUC5B expression (mRNA level by RT-PCR) collected in airway epithelial cells obtained by nasal brushing. The secondary aim is to assess : MUC1, MUC2, MUC4, MUC5AC, MUC7 expression (mRNA level) in airway epithelial cells obtained by nasal brushing; Lund-Kennedy score; TNK-alpha, IL-6, IL-8 in blood plasma. This study is a double parallel, controlled double blind, randomized clinical trial : LCPUFA n-3 (1 g/day) vs placebo for 6 weeks. 30 subjects will be included in this study. Primary and secondary study end point will be assessed two times: before randomization and after 60 days of treatment.

Statistical analysis :

Treatment group and placebo will be compared using U-Mann-Whitney, intention to treat and per protocol.

Primary Outcome Measure : Mucin MUC5B (mRNA level) in native airway epithelial cells obtained by nasal brushing

Secondary Outcome Measures : Mucin MUC1, MUC2, MUC4, MUC5AC, MUC7 (mRNA level) in native airway epithelial cells obtained by nasal brushing.

Lund-Kennedy score TNF-alpha, IL-6, IL-8 in plasma

Inclusion Criteria :

• Cystic fibrosis patient
• Aged 18 to 30 year
• No modification of long term therapy (Corticoids, antibiotics, pancreatic extract, antiacid) before 4 weeks before randomization

Exclusion Criteria:

• Awaiting transplantation
• Patients on anticoagulants
• Contraindication to supplementation with polyunsaturated fatty acids
• Taking antibiotics in progress ( less than 15 days)
• Taking anti- inflammatory ongoing (more than one week per month , steroids , or nonsteroidal )