Send to

Choose Destination
Open Forum Infect Dis. 2018 Jan 5;5(2):ofy002. doi: 10.1093/ofid/ofy002. eCollection 2018 Feb.

Low Levels of Immunoglobulins and Mannose-Binding Lectin Are Not Associated With Etiology, Severity, or Outcome in Community-Acquired Pneumonia.

Siljan WW1,2,3, Holter JC1,2,3, Nymo SH2,3, Husebye E1,3, Ueland T2,3,4,5, Skattum L6,7, Bosnes V8, Garred P9,10, Frøland SS2,3,11, Mollnes TE4,5,12,13,14, Aukrust P2,3,11,13, Heggelund L1,3.

Author information

Department of Internal Medicine, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway.
Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway.
Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
Research Laboratory, Nordland Hospital, Bodø, Norway.
Faculty of Health Sciences, K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway.
Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden.
Clinical Immunology and Transfusion Medicine, Region Skåne, Lund, Sweden.
Department of Immunology, Section of Medical Immunology, Oslo University Hospital Ullevaal, Oslo, Norway.
Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Copenhagen, Denmark.
Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway.
Department of Immunology, Faculty of Medicine, University of Oslo, Oslo, Norway.
K.G. Jebsen Inflammatory Research Center, University of Oslo, Oslo, Norway.
Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway.



Disease severity and outcome in community-acquired pneumonia (CAP) depend on the host and on the challenge of the causal microorganism(s). We measured levels of immunoglobulins (Igs) and complement in 257 hospitalized adults with CAP and examined the association of low levels of Igs or complement to microbial etiology, disease severity, and short-term and long-term outcome.


Serum Igs were analyzed in blood samples obtained at admission and at 6 weeks postdischarge if admission levels were low. Serum complement deficiencies were screened with a total complement activity enzyme-linked immunosorbent assay (ELISA), with further analyzes performed if justified. Disease severity was assessed by the CURB-65 severity score. Short-term outcome was defined as a composite end point of intensive care unit (ICU) admission and 30-day mortality, and long-term outcome as 5-year all-cause mortality.


At admission, 87 (34%) patients had low levels of at least 1 Ig, with low IgG2 as the most prevalent finding (55/21%). IgG levels were lower in bacterial than viral CAP (8.48 vs 9.97 g/L, P = .023), but low Igs were not associated with microbial etiology. Fifty-five (21%) patients had low lectin pathway activity, of which 33 (13%) were mannose-binding lectin (MBL) deficient. Low admission levels of any Ig or MBL were not associated with disease severity, short-term outcome, or long-term outcome. Excluding patients defined as immunocompromised from analysis did not substantially affect these results.


In hospitalized adults with CAP, low admission levels of Igs or complement were in general not associated with microbial etiology, disease severity, short-term outcome, or long-term outcome.


complement; etiology; immunoglobulin; mannose-binding lectin; mannose-binding protein-associated serine proteases; mortality; pneumonia

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central Icon for Norwegian BIBSYS system
Loading ...
Support Center