**8. No smoking COPD and antitissular antibody**

To date, Birringer et al have perhaps been the only ones who have been systematically studied COPD in nonsmokers. Four hundred consecutive patients who visited for 2 years, Birringer found that 25% of them were smokers. Once discarded asthmatics, patients with bronchiectasis and a small subgroup with sputum eosinophilia, they were probably nonreversible asthma, a small percentage of 4% had common characteristics: they were preferably female, with age over 50 years, often with a history of Hashimoto's thyroiditis and / or antithyroid antibodies and / or antitissular antibodies or other features of autoimmune disease. Therefore, the measurement of antithyroid antibodies should be included in patients with features similar.

COPD: Differential Diagnosis 111

Fig. 2. A 36-year old woman was seen in pneumology clinic because of dyspnea. She had a 5-pack-year history of smoking but had stopped smoking 4 year earlier CT: thin-walled

cystic. Pulmonary function testing reveals an obstructive pattern. Lung biopsy:

Lymphangioleiomyomatosis.
