Low and high serum IgG associates with respiratory infections in a young and working age population

• Main Authors: Holma, P. (Pia), Pesonen, P. (Paula), Karjalainen, M. K. (Minna K.), Järvelin, M.-R. (Marjo-Riitta), Väyrynen, S. (Sara), Sliz, E. (Eeva), Heikkilä, A. (Anni), Seppänen, M. R. (Mikko R. J.), Kettunen, J. (Johannes), Auvinen, J. (Juha), Hautala, T. (Timo)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2023
• Subjects: Adaptive immunity; Birth cohort; Immunoglobulins; Pneumonia; Respiratory tract infections; Smoking; Northern Finland
• Online Access: http://urn.fi/urn:nbn:fi-fe20230929137799

Abstract Background: We investigated health consequences and genetic properties associated with serum IgG concentration in a young and working age general population. Methods: Northern Finland Birth Cohort 1966 (NFBC1966, n = 12,231) health data have been collected from birth to 52 years of age. Relationships between life-long health events, medications, chronic conditions, lifestyle, and serum IgG concentration measured at age 46 years (n = 5430) were analysed. Regulatory mechanisms of serum IgG concentration were considered. Findings: Smoking and genetic variation (FCGR2B and TNFRSF13B) were the most important determinants of serum IgG concentration. Laboratory findings suggestive of common variable immunodeficiency (CVID) were 10-fold higher compared to previous reports (73.7 per 100,000 vs 0.6–6.9 per 100,000). Low IgG was associated with antibiotic use (relative risk 1.285, 95% CI 1.001–1.648; p = 0.049) and sinus surgery (relative risk 2.257, 95% CI 1.163–4.379; p = 0.016). High serum IgG was associated with at least one pneumonia episode (relative risk 1.737, 95% CI 1.032–2.922; p = 0.038) and with total number of pneumonia episodes (relative risk 2.167, 95% CI 1.443–3.254; p < 0.001). Interpretation: CVID-like laboratory findings are surprisingly common in our unselected study population. Any deviation of serum IgG from normal values can be harmful; both low and high serum IgG may indicate immunological insufficiency. Critical evaluation of clinical presentation must accompany immunological laboratory parameters. Funding: Oulu University Hospital VTR, CSL Behring, Foundation for Pediatric Research.