Pulmonary Histopathology Findings in Patients With STAT3 Gain of Function Syndrome

Introduction and Aim Multiorgan autoimmunity and interstitial lung disease (ILD) are reported in patients with STAT3 GOF syndrome. Results We present lung histopathology findings in 3 such children, two of whom underwent wedge biopsies with adequate diagnostic material. Wedge biopsies showed interstitial cellular expansion with linear and nodular aggregates of CD8 positive T lymphocytes, plasma cells, and histiocytes; consistent with lymphocytic interstitial pneumonia pattern (LIP). CD4+ T cells and CD20+ B cells were present but infrequent in the interstitium. FOXP3 cells ranged from 0-5%. Focal interstitial and intraalveolar histiocytes were also seen. Neutrophils and eosinophils were rare/absent. Non-occlusive peribronchial lymphoid aggregates showed equal T and B cells; likely reactive in nature. Pulmonary vessels appeared normal without vasculitis or hypertensive change. There was no interstitial or subepithelial fibrosis or organizing pneumonia. Interlobular septa and visceral pleura were unremarkable. Conclusion Children with multi-system autoimmune disorders with ILD should be investigated for STAT3 GOF syndrome. Lung wedge biopsies are more informative than transbronchial biopsies, if a tissue sampling is indicated. CD8 dominant T cell inflammation seems to be a key driver of ILD. Although interstitial fibrosis was not seen in our small sample, longer follow up is needed to understand the natural history.

Asymptomatic Lymphocytic Interstitial Pneumonia with Extensive HRCT Changes Preceding Sjogren’s Syndrome

Lymphocytic interstitial pneumonia (LIP) is a rare condition, commonly associated with Sjogren’s syndrome (SS). We report a 53-year-old woman with an incidental finding of an abnormal chest radiograph. LIP was diagnosed based on high-resolution computed tomography and lung biopsy, but treatment was not initiated. Six years later, she developed cough and dyspnoea, associated with dry eyes, dry mouth, and arthralgia. While being investigated for the respiratory symptoms, she developed cutaneous vasculitis and was treated with 1 mg/kg prednisolone, which resulted in the improvement of her respiratory symptoms. Physical examination revealed fine bibasal crepitations, active vasculitic skin lesions, and a positive Schirmer’s test. Investigations revealed a restrictive pattern in the pulmonary function test, stable LIP pattern in HRCT, and positive anti-Ro antibodies. She was treated with prednisolone and azathioprine for 18 months, and within this time, she was hospitalised for flare of LIP, as well as respiratory tract infection on three occasions. During the third flare, when she also developed cutaneous vasculitis, she agreed for prednisolone but refused other second-line agents. To date, she remained well with the maintenance of prednisolone 2.5 mg monotherapy for more than one year. The lessons from this case are (i) patients with LIP can be asymptomatic, (ii) LIP can precede symptoms of SS, and (iii) treatment decision for asymptomatic patients with abnormal imaging or patients with mild severity should be weighed between the risk of immunosuppression and risk of active disease.

Lymphocytic interstitial pneumonia: computed tomography findings in 36 patients

Objective: To analyze the computed tomography (CT) findings of lymphocytic interstitial pneumonia (LIP). Materials and Methods: We retrospectively reviewed the clinical and CT findings of 36 patients with LIP, including 25 women and 11 men, with a mean age of 52.5 years (age range, 22-78 years). Results: The main associated diseases with LIP were Sjögren syndrome (42%), human immunodeficiency virus infection (17%), amyloidosis (17%), Sjögren syndrome associated with secondary amyloidosis (11%), idiopathic (8%), and systemic lupus erythematosus (5%). The predominant CT abnormalities were multiple cystic airspaces (n = 35), small nodules (n = 15), ground-glass opacities (n = 13), bronchiectasis and/or bronchiolectasis (n = 8), and thickening of the bronchovascular bundles (n = 8). Other CT findings included reticular opacities (n = 7), calcified nodules (n = 4), airspace consolidation (n = 4), emphysema (n = 3), honeycombing (n = 3), lymph node enlargement (n = 2), mosaic attenuation pattern (n = 1), and cavitated nodules (n = 1). Conclusion: The main CT findings of LIP were multiple cysts, small nodules, and ground-glass opacities.