Immune deficiency and the lung

The lungs are particularly vulnerable to infection; respiratory infections are common presenting features of primary immune deficiency (PID). Warning signs include recurrent, severe or invasive infections and poor weight gain. Understanding immune defects helps target investigations and management. Particular patterns of infection point to particular PIDs. Congenital antibody deficiencies are most common and feature recurrent pneumonia and bronchiectasis. Fungal pneumonia is seen in chronic granulomatous disease, lung abscesses are seen in Hyper IgE syndrome, and interstitial pneumonia in SCID and Hyper IgM syndrome. Lymphocyte subset analysis and specific antibody responses to vaccinations are useful investigations in addition to immunological measurements. Early diagnosis and referral for treatment greatly improve outcome.