Evidence Hub

Isolated IgG4-related lung disease: a case report

Jia-Yuan Pu, Pan-Pan Gou, Wan-Chun Qiu, Fabing Tang, Cai-Yun Wang

AME Case Reports, 2026

Abstract

Background: IgG4-related disease (IgG4-RD) represents a chronic, immune-driven fibroinflammatory condition capable of affecting diverse organ systems; within this spectrum, pulmonary involvement (IgG4-RLD) remains comparatively uncommon. This case report outlines the clinical, imaging and pathological features of a patient with IgG4-related lung disease.

Case description: We report a 60-year-old male patient with recurrent fever, chest pain, and cough with hemoptysis. Chest computed tomography (CT) initially showed right upper lobe lesions suggestive of pneumonia, but the patient failed to respond to multiple courses of antibiotics including levofloxacin, nemonoxacin malate, ceftizoxime, and amoxicillin. Further investigations revealed significantly elevated serum IgG4 level (266 mg/dL). Endobronchial ultrasound-guided transbronchial lung cryobiopsy (EBUS-GS-TBLC) confirmed dense lymphoplasmacytic infiltration in the lung tissue, with IgG4-positive plasma cells >50 per high powered field (HPF) and IgG4-positive/IgG-positive cell ratio >50%, consistent with the diagnosis of IgG4-related interstitial lung disease. The patient was treated with oral cyclosporine and mycophenolate mofetil, resulting in significant clinical and radiological improvement.

Conclusions: IgG4-RLD should be considered in the differential diagnosis of patients with pulmonary lesions unresponsive to antibiotic therapy. Comprehensive evaluation including serum IgG4 measurement and targeted pathological…

How strong is the evidence?

Evidence Hub reads this as a case report, done in people. Its evidence level is 5 of 5 (Very low · case / narrative / animal / in vitro / in silico). Case reports, narrative reviews, and animal, cell or computer-model studies give the weakest evidence for human health.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free