Immune-inflammatory Proteome of Elite Ice Hockey Players Before and After SARS-CoV-2 Infection


Regular moderate-to-vigorous exercise has been associated with a strong and timely immune response against infections, reducing susceptibility to acute respiratory illness, and protecting from severe COVID-19 outcomes (1,2). Frequent high intensity training has been proposed to enhance vaccine- induced cellular and humoral immunity (1). However, long-term high-intensity physical activity and stressors associated with elite sports might cause hyperinflammation in some individuals and increase the risk of respiratory illness, and ice hockey (IH) players are among those winter sport athletes with the highest incidence thereof (2,3). Proteomic profiling of COVID-19 patients has proven valuable in the discovery of novel biomarkers associated with disease susceptibility, course, complications and severity (4), but so far there are no reports of COVID-19 proteomic studies in athletes.



Approval was obtained from the Cantonal Ethics Committee of Zurich for the execution of questionnaires, formation of cohorts, in-vitro-experiments and biobank, declaration of consent, incorporation of lab material & results and protection of personal data.


The collection of data and biological material from athletes of different ages and disciplines signifies the establishment of the first Swiss Registry and biobank of sportsmen and women. The currently existing SIAF biobank with full capacity and biobanking SOPs will be used without any additional costs except individual material costs.


The immune-inflammatory proteome of 24 elite IH players before and after a team-wide COVID-19 outbreak with the omicron BA.1 variant was examined. Blood samples and questionnaire data were obtained 3 months prior to COVID-19 and within 1-2 weeks after nasal swab PCR-confirmed SARS- CoV-2 infection. 20 controls (non-IH players) were also assessed after recent recovery from COVID-19. Proximity extension assay (PEA) technology by OLINK was used for targeted proteomic serum analyses of 180 proteins (immune response and inflammation panels).


Controls reported a higher prevalence of symptoms, especially respiratory symptoms. Proteomic analyses identified 28 differentially expressed immune response and inflammation proteins in IH players with a distinct representation of biological process networks. Similar process networks were present both pre- and post-COVID-19 (e.g., lymphocyte proliferation and inflammatory response). The post-COVID-19 profile of IH players was marked by an increase in proteins involved in immune response to viral infection, neutrophil activation, IL-12/- 15/-18 and IFNγ-signaling. Comparison of IH players with post- COVID-19 control samples revealed similar proteomic patterns, with only CCL11 showing a significantly higher expression in controls.


Immune-inflammatory proteomic profiles of elite IH players differ pre- and post-COVID-19. The cause for this might be multi-factorial, e.g., direct impact of the recent SARS-CoV-2 infection, seasonal changes, or training-related influences on sampling timepoints. Proteomic profiles did not differ between athletes and controls post-COVID-19, but the higher incidence of symptomatic disease in controls warrants follow-up studies to examine the potential impact of athletic workloads on disease susceptibility, course and vaccination response, and to identify associated biomarkers.


1. Nieman DC. Exercise Is Medicine for Immune Function: Implication for COVID-19. Curr Sports Med Rep. 2021;20(8):395-401. 

2. Maurer DJ, Liu C et al. Physical activity in asthma control and its immune modulatory effect in asthmatic preschoolers. Allergy. 2022;77(4):1216-1230. 

3. Orysiak et al. Mucosal immunity and upper respiratory tract infections during a 24-week competitive season in young ice hockey players. J 5. Sports Sci. 2017;35(13):1255-1263. 4. Suhre K, et al. Identification of Robust Protein Associations With COVID-19 Disease Based on Five Clinical Studies. Front Immunol. 2021;12:781100.

Published in Allergy, June 2022