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).
Lymphoid interstitial pneumonia is a form of idiopathic interstitial pneumonia (see Overview of Idiopathic Interstitial Pneumonias). It can occur in children, usually those infected with the human immunodeficiency virus (HIV). Lymphoid interstitial pneumonia can also occur in adults, often those with autoimmune disorders such as plasma cell disorders, Sjögren syndrome (see 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.
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.
Doctors can sometimes hear crackles in the lungs using a stethoscope.
Diagnosis requires chest x-ray, computed tomography (CT), and pulmonary function tests (see Pulmonary Function Testing (PFT)) . Pulmonary function tests usually show a decrease in the amount of air the lungs can hold. Doctors often do bronchoscopy (see Bronchoscopy) and wash segments of the lung with a salt-water solution and then collect the washings (bronchoalveolar lavage) for testing. Children may have abnormalities in their blood proteins that can help establish the diagnosis. If not, and for all adults, lung biopsy is usually necessary.
Prognosis and Treatment
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). One half to two thirds of people are alive 5 years after diagnosis.
Treatment is with corticosteroids, cytotoxic drugs (such as azathioprine or cyclophosphamide), or both, but the effectiveness of these drugs is unknown.
Last full review/revision October 2013 by Harold R. Collard, MD