Purpose: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory coronavirus 2 (SARS-CoV-2) has spread around the world. Differentiation between pure viral COVID-19 pneumonia and secondary infection can be challenging. In patients with elevated C-reactive protein (CRP) on admission physicians often decide to prescribe antibiotic therapy. However, overuse of anti-infective therapy in the pandemic should be avoided to prevent increasing antimicrobial resistance. Procalcitonin (PCT) and CRP have proven useful in other lower respiratory tract infections and might help to differentiate between pure viral or secondary infection. Methods: We performed a retrospective study of patients admitted with COVID-19 between 6th March and 30th October 2020. Patient background, clinical course, laboratory findings with focus on PCT and CRP levels and microbiology results were evaluated. Patients with and without secondary bacterial infection in relation to PCT and CRP were compared. Using receiver operating characteristic (ROC) analysis, the best discriminating cut-off value of PCT and CRP with the corresponding sensitivity and specificity was calculated. Results: Out of 99 inpatients (52 ICU, 47 Non-ICU) with COVID-19, 32 (32%) presented with secondary bacterial infection during hospitalization. Patients with secondary bacterial infection had higher PCT (0.4 versus 0.1 ng/mL; p = 0.016) and CRP (131 versus 73 mg/L; p = 0.001) levels at admission and during the hospital stay (2.9 versus 0.1 ng/mL; p < 0.001 resp. 293 versus 94 mg/L; p < 0.001). The majority of patients on general ward had no secondary bacterial infection (93%). More than half of patients admitted to the ICU developed secondary bacterial infection (56%). ROC analysis of highest PCT resp. CRP and secondary infection yielded AUCs of 0.88 (p < 0.001) resp. 0.86 (p < 0.001) for the entire cohort. With a PCT cut-off value at 0.55 ng/mL, the sensitivity was 91% with a specificity of 81%; a CRP cut-off value at 172 mg/L yielded a sensitivity of 81% with a specificity of 76%. Conclusion: PCT and CRP measurement on admission and during the course of the disease in patients with COVID-19 may be helpful in identifying secondary bacterial infections and guiding the use of antibiotic therapy.

Interleukin-5 (IL-5) antibodies represent a promising therapeutic option for patients with severe eosinophilic asthma. To date, no official treatment response criteria exist. In this study, simple criteria for treatment response applicable to all asthma patients were used to evaluate clinical efficacy and predictors for treatment response in a real-life setting. Data from 42 patients with severe eosinophilic asthma treated with mepolizumab for at least six months were analysed. Simple criteria to assess treatment response in clinical practice were used: increase of FEV1 ≥ 12% or ≥ 200 ml, reduction of blood eosinophils (< 150/μl or < 80% from baseline) and improvement of subjective condition (patient-judged subjective improvement or worsening following therapy). Patients were considered treatment responders if two criteria were fulfilled. Thirty-two out of 42 patients (76% [61–87%]) were classified as responders. Within the groups (responder vs non-responder), treatment with mepolizumab led to significant increase in FEV1 (+ 600 ml vs -100 ml, p = 0.003), oxygenation (+ 8 mmHg vs -3 mmHg, p = 0.001), quality of life (visual analogue scale; + 28% vs − 5%, p = 0.004) and Asthma Control Test (+ 8 vs + 1 points, p = 0.002). In the responder group a significant decrease in the exacerbation rate over 12 months (1.45 vs 0.45, p = 0.002) was observed. Baseline characteristics (sex, BMI, smoking history, allergies, baseline level of eosinophils) did not predict treatment response. Using improvement of lung function, decrease of eosinophils and improvement of subjective condition as response criteria, 76% of treated patients could be classified as treatment responders, demonstrating the efficacy of anti-IL-5 therapy in clinical practice.

Patients after lung transplantation are at risk for life-threatening infections. Recently, several publications on COVID-19 outcomes in this patient population appeared, but knowledge on optimal treatment, mortality, outcomes, and appropriate risk predictors is limited. A retrospective analysis was performed in a German high-volume lung transplant center between 19^th March 2020 and 18^th May 2021. Impact of COVID-19 on physical and psychological health, clinical outcomes, and mortality were analyzed including follow-up visits up to 12 weeks after infection in survivors. Predictive parameters on survival were assessed using univariate and multivariate proportional hazards regression models. Out of 1,046 patients in follow-up, 31 acquired COVID-19 during the pandemic. 12 of 31 (39%) died and 26 (84%) were hospitalized. In survivors a significant decline in exercise capacity (p = 0.034), TLC (p = 0.02), and DLCO (p = 0.007) was observed at follow-up after 3 months. Anxiety, depression, and self-assessed quality of life remained stable. Charlson comorbidity index predicted mortality (HR 1.5, 1.1–2.2; p = 0.023). In recipients with pre-existing CLAD, mortality and clinical outcomes were inferior. However, pre-existing CLAD did not predict mortality. COVID-19 remains a life-threatening disease for lung transplant recipients, particularly in case comorbidities. Further studies on long term outcomes and impact on pre-existing CLAD are needed.

Background: Anti-IL-5 antibodies represent an established therapy for severe eosinophilic asthma (SEA), but some patients show inadequate response. The objective of this study was to assess the effects of a switch to anti-IL-5Rα therapy in patients with inadequate response to anti-IL-5 therapy. Methods: In this retrospective multi-centre, real-life study, we analysed all SEA patients switched from anti-IL-5 to anti-IL-5Rα therapy due to inadequate response or intolerability. Pulmonary function tests, blood gas analyses, asthma control tests (ACT) and oral corticosteroid (OCS) usage were analysed and compared at three timepoints: baseline (BL, before anti-IL-5 therapy), timepoint 1 (T1, under anti-IL-5 therapy) and timepoint 2 (T2, under anti-IL-5Rα therapy). Results: Of 665 patients treated with anti-IL-5 antibodies, 70 were switched to anti-IL-5Rα and 60 were included in the analysis. Median treatment duration was 8 months [IQR 5; 15] for anti-IL-5 and 5 months [IQR 4; 6] for anti-IL-5Rα therapy. FEV₁ was 61% of predicted at BL [IQR 41; 74], 61% [IQR 43; 79] at T1 and 68% [IQR 49; 87] at T2 (p_T1-T2=0.011). ACT score was 10 [IQR 8; 13], 16 [IQR 10; 19] and 19 [IQR 14; 22], respectively (both p< 0.001). The number of patients requiring OCS was reduced from 41 (BL) to 32 (T1) and 19 (T2) (both p< 0.001). Ten patients discontinued anti-IL-5Rα therapy due to insufficient efficacy (n=7) and adverse events (n=3). Conclusion: Switching from anti-IL-5 to anti-IL-5Rα therapy in patients with inadequate response was associated with significantly improved FEV₁, asthma control and OCS reduction.

Alterations in specific signalling pathways within the bone morphogenetic protein/transforming growth factor-β (BMP/TGF-β) family, involving several precisely regulated activator or inhibitor ligands, have been identified as pathogenic drivers of pulmonary arterial hypertension (PAH). These alterations, particularly affecting BMPRII and activin-dependent pathways, have led to innovative therapies, notably the development of sotatercept [1, 2]. Sotatercept, a fusion protein of the extracellular domain of human ACTRIIA and the Fc domain of human IgG1, has shown promising results in improving key clinical, functional, and haemodynamic parameters in PAH patients, as evidenced by positive results in the phase 2 PULSAR and phase 3 STELLAR trials [3, 4]. This progress was partly based on preclinical studies showing that reducing activin-induced Smad2/3 phosphorylation levels, by suppressing activin production in mice [5] or using soluble receptors in rats [6, 7], can attenuate pulmonary vascular remodelling. Despite these advancements, the precise mechanisms of action of these approaches in humans and rodents need to be better understood to enhance these valuable tools. Sotatercept raises several critical questions regarding its mechanism of action, and a deeper understanding could reveal the pathophysiological mechanisms of PAH, leading to more effective therapeutic approaches.