Common and uncommon CT findings in CVID related GL-ILD: correlations with clinical parameters, therapeutic decisions and potential implications in the differential diagnosis

Abstract

Purpose To investigate common and uncommon CT findings in GL-ILD that may be also helpful in differential diagnosis, i.e. with sarcoidosis. To compare CT features with functional and immunological parameters. To look for radiological and non-radiological elements that may be predictive of GL-ILD therapy. Methods We retrospectively described CT features of 38 GL-ILD patients before any specific therapy. Correlations with functional and immunological features were computed. A logistic regression was performed to find a model associated with subsequent GL-ILD therapeutic decisions. Results Most common CT alterations were: bronchiectasis, non-perilymphatic nodules, consolidations, GGO, bands and enlarged mediastinal lymphnodes without calcification. GL-ILD was usually predominant in lower fields. Fibrotic ILD, GGO, reticulations and bronchiectasis were associated with decreased lung performance (p<0.05). Fibrosis, GGO and bronchiectasis were associated with low IgA levels at diagnosis, whereas high CD4+ T cells percentage was related to GGO (p<0.05). 20/38 patients underwent GL-ILD therapy after CT. A multivariate model combining MZ B cells percentage, IgA at diagnosis, CT evidence of lower field consolidations and mediastinal lymphnodes enlargement showed a good discriminatory capacity with regards to GL-ILD treatment (AUC=0.91). Conclusions Most common CT findings in GL-ILD before treatment were small nodules with a non-perilymphatic distribution, consolidations, GGO, bands and bronchiectasis. GL-ILD was usually prevalent in lower fields. A lower fields involvement with non-perylimphatic nodules and a non-traction bronchiectasis pattern could suggest GL-ILD instead of sarcoidosis. MZ B cells percentage, IgA at diagnosis, lower field consolidations and mediastinal lymphnodes enlargement were predictive of a specific GL-ILD therapy.