Current opinion in pulmonary medicine
-
Lymphoid interstitial pneumonitis (LIP) involves a clinicopathologic pattern of pulmonary disease characterized by diffuse interstitial reactive lymphoid infiltrates. In adults, it occurs most commonly in autoimmune diseases, such as Sjögren's syndrome (0.9% of these patients) and primary biliary cirrhosis, whereas in children it is usually seen in HIV infection. Dysproteinemias (hyper- and hypogammaglobulinemia) are found in more than 60% of patients. ⋯ These patterns may be difficult to differentiate from each other. It appears that LIP sometimes evolves to lymphoma; the frequency of this evolution is probably low but is difficult to assess because low-grade lymphomas may mimic LIP. A relatively high frequency of LIP patients have Epstein-Barr virus DNA in their lungs but not all patients with LIP show this finding, suggesting other possible etiologies.