Radiographic airway abnormalities in untreated early rheumatoid arthritis are associated with peripheral neutrophil activation

BACKGROUND

The role of the lung for the initiation and progression of rheumatoid arthritis (RA) is still unclear. Up to 10% of RA patients develop interstitial lung disease which remains a clinical challenge. Understanding early disease mechanisms is of great importance. The objective of this study was to determine whether there is an association between peripheral neutrophil phenotypes and presence of pulmonary abnormalities (PA) on chest high-resolution computed tomography (HRCT) in untreated early RA (ueRA).

METHODS

Clinical data and blood were collected, and HRCT performed at diagnosis on 30 consecutive anti-citrullinated protein antibody (ACPA) and/or rheumatoid factor (RF) positive ueRA patients. HRCTs were evaluated for the presence of RA-associated parenchymal, airway and/or pleural abnormalities. Expression of phenotype markers on neutrophils were determined by flow cytometry. Levels of calprotectin, ACPA and RF were measured using immunoassays.

RESULTS

The frequency of having any PA was 60%. Airway abnormalities were present in 50%, parenchymal nodules in 43% and interstitial lung abnormalities (ILA) in 10%. Unsupervised multivariate data analysis showed clustering of any PA with neutrophil activation, parameters of inflammation and RF titres. In univariate analysis, the patients with PA displayed significantly increased CD11b and decreased CD62L expression on neutrophils (1.2-fold, p = 0.014; 0.8-fold, p = 0.012) indicating activation and significantly increased RF IgM titre and CRP (5.7-fold, p = 0.0025; 2.3-fold, p = 0.0035) as compared to no PA. Titres of RF, but not ACPA, correlated with expression of the neutrophil activation marker CD11b. A stratified analysis demonstrated that airway involvement was the PA subtype with the strongest association with neutrophil activation.

CONCLUSION

We report a strong association between radiographic airway findings and activation of circulating neutrophils in early RA supporting a role of innate immunity and the lung at disease onset. Our results also indicate different contributions of RF and ACPA in the RA pathogenesis.

Changing patterns of pulmonary abnormalities in rheumatoid arthritis

BACKGROUND

As a first step in identifying the developmental pathways of pulmonary abnormalities in rheumatoid arthritis (RA), we sought to determine the existing and changing patterns of pulmonary abnormalities.

METHODS

We conducted a retrospective cohort study of consecutive patients with RA who underwent high-resolution computed tomography before and during biologic therapy. The presence of 20 pulmonary abnormalities and the changes in those abnormalities were recorded. Patterns of pre-existing and changing abnormalities were examined via cluster analysis, and their relationship was also assessed using the Kaplan-Meier method and log-rank test.

RESULTS

A total of 208 subjects were included. Pulmonary abnormalities were observed in 70% of patients: 39% had interstitial lung disease, and 55% had airway disease (AD). Several different pulmonary abnormalities were commonly found to co-exist in several patterns in the same patient. In most patients with pulmonary abnormalities, AD was present alone or in combination with other abnormalities. During the observation period (mean 3.2 years), 172 pulmonary abnormalities had changed in 91 patients: 115 pulmonary abnormalities newly emerged, whereas 42 worsened and 25 demonstrated improvement. Pulmonary abnormalities changed in several patterns. Correlations were observed between pre-existing and new/worsening abnormalities at individual and regional levels, such as new ground-glass opacity (GGO) and pre-existing AD, small nodular patterns, and honeycombing. AD was a possible initial abnormality.

CONCLUSIONS

Pulmonary abnormalities occurred and changed in several patterns, which suggests the existence of developmental pathways of pulmonary abnormalities. AD may play an important role in the development of these abnormalities, including GGO.

Edge map analysis in chest X-rays for automatic pulmonary abnormality screening

PURPOSE

Our particular motivator is the need for screening HIV+ populations in resource-constrained regions for the evidence of tuberculosis, using posteroanterior chest radiographs (CXRs).

METHOD

The proposed method is motivated by the observation that abnormal CXRs tend to exhibit corrupted and/or deformed thoracic edge maps. We study histograms of thoracic edges for all possible orientations of gradients in the range [Formula: see text] at different numbers of bins and different pyramid levels, using five different regions-of-interest selection.

RESULTS

We have used two CXR benchmark collections made available by the U.S. National Library of Medicine and have achieved a maximum abnormality detection accuracy (ACC) of 86.36 % and area under the ROC curve (AUC) of 0.93 at 1 s per image, on average.

CONCLUSION

We have presented an automatic method for screening pulmonary abnormalities using thoracic edge map in CXR images. The proposed method outperforms previously reported state-of-the-art results.