Background: Lung involvement is the most common organ involvement in inflammatory rheumatic disease (IRD). The current state of the art is to perform a high-resolution computed tomography (HRCT) for evaluation and diagnosis. The main pattern in HRCT in IRD included pure ground glass opacity (GGO) as primary inflammatory pattern and non-specific interstitial pneumonia (NSIP) as well as usual interstitial pneumonia (UIP) representing fibrotic pattern.

Objectives: The aim of this study was to characterise HRCT pattern by different immune cells at the time of IRD diagnosis with lung involvement.

Methods: 74 patients with newly diagnosed IRD (connective tissue disease n = 46, myositis n =12, vasculitis n = 10 and rheumatoid arthritis n = 6) as well as newly diagnosed lung involvement in the context of interstitial lung disease (ILD) in HRCT were included in the study. In HRCT, the patients presented pure GGO, NSIP or UIP pattern. The study cohort was divided in a GGO (n = 29) and NSIP/UIP group (n = 45). For the quantification of immune cells an immunological bronchoalveolar lavage was performed, with subsequent implementation of a differential cell image and flow cytometry. Additionally, all patients were naïve for immunosuppressive therapy, received no glucocorticoids and were non-smokers.

Results: In the GGO group, macrophages (relatively +15.3 %) and B-lymphocytes (relatively +95.2 %) were significant higher compared to NSIP/UIP group. Neutrophils were significant lower (relatively -56.6%) in GGO group. No significant difference was observed between the groups for lymphocytes and T-cells (CD3+). Further, intraephithelial lymphocytes (CD4+CD103+) were significant increased (relatively +35.1%) and T-regular cells (CD4+CD25+CD103+) were significant reduced (relatively -26.3 %) in the GGO group. Regarding, T helper cells (CD3+CD4+) and cytotoxic T cells (CD3+CD8+) no significant difference between the GGO versus NSIP/UIP group was detected.

Conclusion: The study present that at the onset of IRD with lLD is associat with an increase of B-lymphocytes and decrease of T-regular cells in GGO HRCT pattern. The reduction of T- regular cells in the immunological BAL is possibly associat with the IRD-ILD. Further studies should be initiated to verify these initial results.

Funding: This study is a part of the Investigator Initiated study “Diagnostic procedures for detection of pulmonary manifestations at the onset of inflammatory rheumatic diseases (IRD)” which is supported by Boehringer Ingelheim Pharma GmbH & Co. KG, Binger Str. 173, 55216 Ingelheim, Germany.

REFERENCES: NIL.

Acknowledgements: NIL.

Disclosure of Interests: None declared.