Clinical characteristics of immunoglobulin G4-positive interstitial pneumonia

Immunoglobulin G 4 -related disease is a systemic disease characterised by tumefactive lesions with abundant IgG 4 -positive plasma cells and elevated serum IgG 4 concentrations [1–4]. We previously assessed IgG 4 -related respiratory disease (IgG 4 -RRD) with extrathoracic manifestations [5]. IgG 4 -RRD develops through the lymphatic routes in the lungs and responds well to corticosteroid therapy with a benign prognosis [5–7]. However, whether interstitial pneumonia (IP) with IgG 4 -positive plasma cell infiltration in the lungs without the extrathoracic lesions of IgG 4 -related disease could be considered a type of IgG 4 -RRD is controversial. This study suggests that IgG 4 + IP with abundant IgG 4 + cells and elevated serum IgG 4 levels could be treated differently from IgG 4 -related respiratory disease due to potential differences in disease behaviour and response to corticosteroid therapy https://bit.ly/3dUo2cu