Abstract Introduction Pulmonary PASC shows significant overlap with autoimmune lung diseases. The risk profile, clinical symptoms, and, in some cases, underlying disease mechanisms are similar to those of CTD-ILD and SARD-ILD. Although the diseases typically manifest with reduced lung function parameters and fatigue, the exact disease mechanisms are not identical and require different therapeutic approaches. The aim of this study is to identify similarities between PASC and autoimmune lung diseases and to systematically investigate the role of immunosuppressive and anti-inflammatory therapeutic approaches in patients with PASC. Methodology The study includes 151 patients, 75 women and 76 men. At the beginning, extensive data was collected, including collagenosis screening, lung function testing with spiroergometry, chest CT, and bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB). Depending on the findings, patients received individually tailored therapy. In the further course of treatment, laboratory chemical parameters and lung function parameters, including spiroergometry, were recorded in order to assess performance development and possible changes in the initial pathological findings. Results The alveolitis-dominant phenotype was the most frequently diagnosed, at 50% (n = 61). Closely followed by the bronchiolitis phenotype in 47 patients (38.5%), we found an asthmatic constellation in 11 patients (9.0%). Only in 3 cases (2.5%) was it not possible to make a clear classification. Depending on the phenotype, a 3-month course of therapy with OCS, azithromycin, and asthma step therapy was administered. After completion of therapy, significant improvements were demonstrated in the overall collective (under the respective individual therapeutic approach). There was a significant reduction in RV/TLC (p = 0.0475), indicating a decrease in pulmonary hyperinflation. Post-therapeutic increased airway patency was demonstrated by the highly significant increase in FEV1 (p = 0.0046). Similarly, a significant improvement was demonstrated for both FVC (p = 0.0074) and DLCO (p = 0,0074). Other variables examined, such as KCO (p = 0.0701), did not reach statistical significance but also indicated a positive development. Conclusion This study demonstrates the value of precise phenotyping of post-COVID patients, as significant improvements in pulmonary performance can be achieved quickly by creating an individualized treatment plan, as has long been practiced in rheumatology for CTD-ILD. Although the multi-layered phenotyping concept presented here represents a complex diagnostic approach, it offers the possibility of providing therapy, in particular to patients who continue to suffer from PASC despite having had the infection a long time ago and who are striving to return to normal everyday life. This abstract is funded by: n/a
Baudrexl et al. (Fri,) studied this question.