Public Defence: William Ward Siljan William Ward Siljan at Institute of Clinical Medicine will be defending the thesis “Immunodeficiencies, immune responses and biomarkers in community-acquired pneumonia” for the degree of PhD (Philosophiae Doctor).

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Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Senior Consultant Adamantia Liapikou, Sotiria Chest Diseases Hospital, Athens, Greece
  • Second opponent: Senior Consultant Torgun Wæhre, Department of Infectious Diseases, Oslo University Hospital
  • Third member and chair of the evaluation committee: Associate Professor Truls Michael Leegaard, Faculty of Medicine, University of Oslo

Chair of the Defence

Head of Department Dag Kvale, Faculty of Medicine, University of Oslo

Principal Supervisor

MD, PhD, Lars Heggelund, Vestre Viken Hospital Trust


Community-acquired pneumonia (CAP) is a common infectious condition, responsible for considerable short- and long-term morbidity and mortality worldwide. Despite advances in diagnosis and care of pneumonia, deaths due to this disease have only slightly decreased over recent decades. Better understanding of the immunological mechanisms underlying CAP could help identify patients at risk of poor outcomes, lead to a reduction in antimicrobial overuse and even reveal new therapeutic targets.

Over a three-year period 267 patients admitted with CAP to Drammen Hospital were included in this study and followed for 5 years after hospital discharge. Patients were assessed at three time points with extensive clinical, laboratory and microbiological testing.

The study aimed to shed light on host immune responses and potential immunodeficiencies in CAP and examine whether these factors were associated with different microbial patterns, disease severity, and outcomes. Further, we aimed to identify new diagnostic and prognostic biomarkers that could help important clinical decisions in CAP.

For most of the immune mediators examined, including complement factors, immunoglobulins, and cytokines, only minor non-significant variations were seen for different microbial patterns, disease severity and outcomes. Additionally, the presence of low levels of mannose-binding lectin, a complement factor deficient in 10-15% of the Nordic population, or low immunoglobulins, a cornerstone of host immunity against invading pathogens, were not associated with differences in endpoints.

However, circulating cell-free DNA, pentraxin 3 and presepsin were markers of short-term prognosis, while calprotectin was both a marker of bacterial CAP, but also of 5-year mortality in this cohort.

Overall, in this CAP study, we did not find major differences in host immune responses compared by microbial patterns, disease severity or outcomes, but several new markers with potential clinical utility were identified and should be investigated in future CAP cohorts.

Additional information

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Published Mar. 15, 2019 10:26 AM - Last modified Mar. 15, 2019 2:34 PM