Characterizing Patients With Sarcoidosis With Obstructive Respiratory Physiology

Area of Science:

• Pulmonary Medicine
• Immunology
• Granulomatous Diseases

Background:

• Sarcoidosis frequently affects the lungs (>95% of cases).
• Current assessment tools lack PFT-based likelihood of lung involvement.
• Understanding PFT patterns in sarcoidosis is incomplete.

Purpose of the Study:

• Determine the frequency of obstructive (OP), restrictive (RP), and normal pulmonary function tests (PFTs) in sarcoidosis.
• Identify laboratory parameters associated with these PFT patterns.

Main Methods:

• Evaluated 253 sarcoidosis patients, categorizing them by PFT findings (OP, RP, normal).
• Correlated PFTs with demographic, clinical, and laboratory data.
• Analyzed select PFT abnormalities against Olink protein panels.

Main Results:

• 64% had normal PFTs, 20% OP, and 15% RP.
• Abnormal PFTs were more common in males.
• Lower lymphocyte percentage in OP vs RP; lower soluble IL-2 receptor in OP vs normal; lower C-reactive protein in OP and normal vs RP.
• RP associated with less splenic involvement.

Conclusions:

• Normal spirometry is most common in sarcoidosis.
• Obstructive lung disease is more frequent than restrictive lung disease when PFTs are abnormal.
• Potential differences in immune mechanisms exist between PFT groups.
• Serum protein analysis may yield biomarkers for physiological abnormalities and guide management.