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-BETA-1 ASSAY

The case of a 3-month-old boy with lymphoid interstitial pneumonia (LI P) is reported. He had cough and tachypnea, his weight gain was poor a nd a chest radiograph showed microgranular shadows in almost all lung areas. Histological investigations revealed severe cellular infiltrati on by a variety of lymphoid and plasma cells with lymphoid follicle fo rmation in the alveolar walls and also around the bronchioles. Foamy m acrophages, a few lymphocytes and exudate filled the alveolar spaces. Epithelial cells lining the air spaces expressed human leukocyte antig en (HLA)-DR. Lymphocytes and macrophages in the alveolar spaces expres sed transforming growth factor (TGF)-beta strongly. Serum TGF-beta 1 c oncentrations were measured eight times during the course of his illne ss. They exceeded the upper end of the normal range in four samples an d were within it in the others. These results suggested that dysfuncti on of the immune system, especially abnormal expression of HLA-DR in n on-immune cells and exaggerated production of TGF-beta, played importa nt roles in the pathogenesis of LIP in this patient.