Serum Surfactant Protein-D as Predictor of Disease Severity in Hospitalized COPD Patients

Chronic Obstructive Pulmonary Disease (COPD) is a chronic progressive inflammatory disease of the airways and lungs, mainly caused by cigarette smoking and environmental exposures .It is characterized by airflow limitation that is not fully reversible, with exacerbations and systemic manifestations.

In COPD, there is a significant immune dysregulation, involving both innate and adaptive immune responses.Surfactant Protein D (SP-D) is a lung-specific collectin, produced primarily by alveolar type II cells and Clara cells.SP-D plays a key role in the innate immune defense of the lungs, particularly in modulating inflammation, enhancing phagocytosis, and neutralizing pathogens.

In COPD, the epithelial barrier is compromised, leading to increased leakage of SP-D from the lungs into the bloodstream.As a result, serum levels of SP-D are elevated in COPD patients, and this elevation is positively associated with disease severity and exacerbation frequency.

.SP-D has been proposed as a non-invasive biomarker for COPD severity, progression, and response to therapy.Several studies support the use of SP-D as a marker of systemic inflammation and lung tissue damage in COPD.Measuring serum SP-D could provide a valuable tool for early detection, monitoring progression, and personalizing management of COPD patients.Surfactant protein D (SP D) as a prognostic biomarker needs further studies to validate its clinical applicability.

Inclusion criteria

• Adults ≥40 years diagnosed with COPD based on prior diagnosis or spirometry if available.
• Admission for acute exacerbation (AECOPD) in ward or Respiratory ICU.

Exclusion criteria

• Active pulmonary infection unrelated to COPD (e.g. tuberculosis, fungal infections)
• Other chronic lung diseases such as asthma, interstitial lung disease, or lung cancer
• Use of systemic corticosteroids for conditions other than COPD exacerbation