A case of lymphoid interstitial pneumonia in a 3-month-old boy not associated with HIV infection: Immunohistochemistry of lung biopsy specimens and serum transforming growth factor-β1 assay

The case of a Smonthold boy with Iymphoid Interstitial pneumonia (LIP) is reported. He had cough and tachypnea, his weight gain was poor and a chest radiograph showed microgranular shadows in almost all lung areas. Histological Investigations revealed severe cellular Infiltration by a variety of Iymphoid and plasma cells with lymphoid follicle formation in the alveolar walls and also around the bronchioles. Foamy macrophages, a few lymphocytes and exudate filled the alveolar spaces. Epithellal cells lining the air spaces expressed human leukocyte antigen (HLA)-DR. Lymphocytes and macrophages In the alveolar spaces expressed transforming growth factor (TGF)-β strongly. Serum TGF-β1 concentrations were measured eight times during the course of his Illness. They exceeded the upper end of the normal range In four samples and were with in it in the others. These results suggested that dysfunction of the Immune system, especially abnormal expression of HLA-DR in non-immune cells and exaggerated production of TGF-β, played Important roles in the pathogenesis of LIP In this patient.