Abstract Introduction Granulomatous Lymphocytic Interstitial Lung Disease (GLILD) is a rare histopathologic lung manifestation associated with Common Variable Immunodeficiency Disease (CVID). GLILD has a low prevalence, even among individuals with CVID, and its exact pathophysiology remains poorly understood. We present an atypical case of GLILD in the setting of isolated IgG hypogammaglobulinemia and monoclonal B-cell lymphocytosis in a patient who does not meet criteria for a CVID diagnosis. Case A 63-year-old woman with a history of Graves’ disease, chronic urticaria, low IgG (519), recurrent respiratory infections, poor response to pneumococcal vaccinations, and monoclonal B-cell lymphocytosis was found to have incidental ground-glass pulmonary micronodules with mid-to-upper zone predominance, which have been progressing on imaging over the course of one year. Though largely asymptomatic with normal PFTs, biopsy revealed multifocal interstitial lymphoid aggregates with T-cells, monoclonal B-cells, and poorly formed non-necrotizing granulomas. This is most consistent with GLILD, but with a tissue manifestation of her monoclonal B-cell lymphocytosis. Specialist consensus across different institutions, initially hesitant due to a lack of CVID diagnosis, favored a diagnosis of GLILD. Her presentation was also notable for a pneumothorax due to an apical bleb, which was thought to be unrelated. Discussion GLILD pathophysiology is thought to be driven by systemic immune dysregulation, predominantly mediated by B-cell hyperplasia and granuloma formation, and is associated with autoimmune and lymphoproliferative disorders. Imaging may show solid or ground glass nodules of varying sizes, however, features are often nonspecific. Our patient has histopathology and history highly suggestive of GLILD, despite not fully meeting the criteria for CVID. She has an isolated IgG deficiency with normal IgA and IgM, and a past medical history consistent with immune dysregulation. GLILD has been described in immunodeficiencies other than CVID a handful of times, such as selective IgA deficiency and 22q11DS. Furthermore, it mimics a range of diseases on imaging, including sarcoidosis, hypersensitivity pneumonitis, and autoimmune ILD, making diagnosis challenging. If left untreated, GLILD can lead to significant disease progression, highlighting the importance of serial PFTs and HRCT with a low treatment initiation threshold in suggestive cases. Conclusion This case underscores the importance of considering GLILD in patients with immune dysregulation who do not meet the diagnostic criteria for CVID. Further studies are needed to elucidate the underlying pathophysiology of GLILD and its relationship to broader immune system dysregulation as timely recognition and multidisciplinary evaluation are crucial for management and control of disease progression. This abstract is funded by: None
Nasser et al. (Fri,) studied this question.