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Lymphoid Interstitial Pneumonia

(Lymphocytic Interstitial Pneumonitis)

ByJoyce Lee, MD, MAS, University of Colorado School of Medicine
Reviewed/Revised Jun 2025 | Modified Jul 2025
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Lymphoid interstitial pneumonia is an uncommon lung disease in which mature lymphocytes (a type of white blood cell) accumulate in the air sacs of the lungs (alveoli).

  • People usually cough and have difficulty breathing.

  • Diagnosis requires chest x-ray, computed tomography, pulmonary function tests, and often bronchoscopy, biopsy, or both.

  • Treatment involves steroids, other immunosuppressants, or both.

(See also Overview of Idiopathic Interstitial Pneumonias.)

Lymphoid interstitial pneumonia is a form of idiopathic interstitial pneumonia. It can occur in children, usually those who have human immunodeficiency virus (HIV) infection or other immunodeficiencies. Lymphoid interstitial pneumonia can also occur in adults, often those with autoimmune disorders such as plasma cell disorders, Sjögren syndrome, Hashimoto thyroiditis, rheumatoid arthritis, and systemic lupus erythematosus (lupus). Women and girls are more commonly affected. Average age of affected adults is 54 years.

Symptoms of Lymphoid Interstitial Pneumonia

Children develop cough and decreased ability to exercise, and they may not grow and gain weight. Adults develop difficulty breathing and cough over months or, in some cases, years. Less common symptoms include weight loss, fever, joint pain, and night sweats.

Diagnosis of Lymphoid Interstitial Pneumonia

  • Chest computed tomography

Diagnosis requires chest x-ray, computed tomography (CT), and pulmonary function testing. Pulmonary function tests usually show a decrease in the amount of air the lungs can hold. Doctors sometimes do bronchoscopy and wash segments of the lung with a salt-water solution and then collect the washings (bronchoalveolar lavage) for testing.

In affected people, blood tests may reveal abnormalities in the blood proteins that can help establish the diagnosis. If not, lung biopsy is usually necessary.

Treatment of Lymphoid Interstitial Pneumonia

  • Steroids or other immunosuppressant medications

The prognosis is difficult to predict. The disorder may resolve on its own or after treatment, or it may progress to lung fibrosis or lymphoma (a cancer).

Treatment is with steroids (sometimes called glucocorticoids or corticosteroids), immunosuppressant medications (such as azathioprine or cyclophosphamide), or both, but the effectiveness of these medications is unknown.Treatment is with steroids (sometimes called glucocorticoids or corticosteroids), immunosuppressant medications (such as azathioprine or cyclophosphamide), or both, but the effectiveness of these medications is unknown.

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