Published online Nov 28, 2018. doi: 10.4329/wjr.v10.i11.172
Peer-review started: July 17, 2018
First decision: August 8, 2018
Revised: September 22, 2018
Accepted: October 7, 2018
Article in press: October 7, 2018
Published online: November 28, 2018
Common variable immunodeficiency disorders (CVID) are the most clinically significant group of humoral primary immunodeficiency diseases (hPIDs), manifesting with recurrent respiratory tract infections and increased susceptibility to autoimmune diseases and malignancy. Other hPIDs are often termed “CVID-like” conditions, and include selective IgA deficiency and isolated IgG subclass deficiency. The initial evaluation of patients newly diagnosed with hPIDs should include high-resolution computed tomography (HRCT) and pulmonary function tests (PFTs).
To the best of our knowledge no previous studies assessed whether HRCT findings differ in terms of prevalence among the two subtypes of hPIDs in adult patients. Demonstrating a difference between CVID and CVID-like patients may influence the time intervals between HRCT examinations during follow-up in these 2 subgroups of hPIDs. Moreover, previous studies assessing a possible correlation between HRCT findings and PFTs results demonstrated contradictory results.
The purpose of this study was twofold: (1) to compare HRCT pulmonary findings in adult patients with different subgroups of hPIDs (i.e., CVID vs CVID-like); and (2) to assess whether HRCT findings predict PFTs results.
We included 52 adult patients (38 CVID and 14 CVID-like) who received a definite diagnosis of hPIDs and underwent HRCT and PFTs within one month from the time of diagnosis. One pulmonary radiologist, blinded to patient history and lung function: (1) reviewed the HRCT examinations; (2) recorded two classes of abnormalities, namely airway abnormalities and/or parenchymal-interstitial abnormalities; and (3) scored all abnormalities according to their extension and conspicuity. We calculated the per-patient prevalence of each HRCT abnormality in the overall population and in both subgroups of hPIDs patients, (CVID and CVID-like groups). We performed a logistic regression analysis to assess whether HRCT findings were predictive of a relevant obstructive or restrictive defect at PFTs on the overall study population.
Of the 52 hPIDs patients, 37 were females and 15 were males, with a mean age of 53.9 ± 12.7 years. We found a high prevalence of HRCT findings (90.4% patients had one or more abnormalities). The prevalence of each of the airway abnormalities considered was not significantly different between the CVID and CVID-like group. Regarding HRCT-detected parenchymal-interstitial abnormalities, the only relevant result was the finding of linear and/or irregular opacities, showing a prevalence of 31.6% in the CVID group and 0 in the CVID-like group, with borderline significance. The presence of tree-in-bud abnormalities was an independent predictor of obstructive defects at PFTs (Odds Ratio, OR, of 18.75, P < 0.05), while the presence of linear and/or irregular opacities was an independent predictor of restrictive defects at PFTs (OR = 13.00; P < 0.05).
No previous research compared the prevalence of HRCT findings in different subtypes of hPIDs adult patients. After dividing hPIDs patients in CVID vs CVID-like groups, we observed no significant difference in the prevalence of most of airways and parenchymal-interstitial findings between the two groups. This observation supports the hypothesis that these two groups represent comparable hPIDs subtypes, and are candidate to similar management. Tree-in-bud and linear and/or irregular opacities were found to be independent predictors of, respectively, obstructive and restrictive defects on PFTs.
Our results suggest that morphological assessment with HRCT might be delayed as much as possible to maximize cost-effectiveness and reduce radiation exposure. A possible exception to this might be the case of patients showing tree-in-bud or linear and/or irregular opacities: Scheduling HRCTs at shorter intervals for these patients might provide a reliable morphological counterpart of pulmonary function. Further prospective studies with a proper design are needed to confirm this hypothesis in the follow-up period.