Interstitial pneumonitis Lymphocytic interstitial pneumonia Lymphocytic interstitial pneumonitis is a benign lymphoproliferative disorder of the lung that is characterized by the presence of a dense, predominantly lymphocytic interstitial infiltrate (lymphocytes, plasma cells, other elements of the lymphoreticular system) that expands the alveolar septa. Lymphoid interstitial pneumonia Lymphoid interstitial pneumonitis SNOMEDCT_US:44274007 HP:0006527 UMLS:C0264511 Lymphocytic interstitial pneumonitis is assumed to be a pathological immunologic response to different triggers and are particularly associated with autoimmune and infectious diseases as well as immunodeficiency. Associated clinical manifestations often include fever, cough, and shortness of breath. Lymphocytic interstitial pneumonitis Pulmonary interstitial lymphocyte infiltration