Granulomatous pneumonitis due to perforin defect – A case report

Abstract

A 6-year-old girl presented with dry cough and fatigue for 3 weeks, not associated with fever, elevation in inflammatory markers or evidence of a systemic disease. Chest X-rays showed consolidation of the lower lobes and fine reticular opacities in the upper lobes. Lung function was decreased and high inspiratory O 2 concentration was required. Lung biopsy showed extensive focal lymphoid infiltration with many granulomas, often small and loose. Necrosis and vasculitis were absent, and infective organisms were not found. An obvious immune defect was not identified. Due to a history of exposure to tea tree spray, hypersensitivity pneumonitis was suggested. Marked improvement followed steroids, but on reduction there was recurrence. Repeat biopsy showed considerably increase in the inflammatory infiltration. Familial lymphohistiocytosis (FLH) was considered even though clinical and laboratory features of haemophagocytic lymphohistiocytosis were absent. Immunofluorescence showed marked reduction in the intracellular perforin expression in the NK cells. K285del/A91 V mutation was found in the PERF1 gene. A bone marrow transplant was performed. The possibility of FLH should be considered in older children and adults when an obvious cause of granulomatous lesion in the lungs and other organs cannot be identified. Bone marrow transplant can sometimes be curative.