Does the frequency of respiratory tract infections help to identify humoral immunodeficiencies in a primary health-care cohort?

Abstract

Background: Primary immune deficiency (PID) due to humoral defects is associated with recurrent respiratory tract infections (RTIs). Reliable clinical warning signs of PID would facilitate early diagnosis and thereby reduce long-term complications. The aim of the present study was to evaluate the accuracy of the warning sign, ‘four or more antibiotic-treated RTIs annually for 3 or more consecutive years,’ for detecting PID among adults in a primary health-care setting. Methods: Fifty-three cases with ‘four or more antibiotic-treated RTIs annually for 3 or more consecutive years’ were selected from a Swedish primary health-care registry of RTIs. In addition, 66 age- and sex-matched controls were selected having a maximum of one antibiotic-treated RTI during the period covered by the study. Levels of immunoglobulin (Ig) IgG, IgA, IgM, IgG subclasses, and IgG antibodies against Haemophilus influenzae and Streptococcus pneumoniae as well as the inflammatory markers, C-reactive protein, interleukin (IL)-6 and IL-8 were determined. Results: IgG subclass deficiencies (IgGsd) were found in 5/53 (9.4%) of the cases and in 7/66 (10.6%) controls. The most frequent deficiency was IgG3sd and this was found in three participants in the case group and seven in the control group. The mean level of IgG3 was lower in the control group (p = 0.02). The mean level of IL-8 was lower in the case group (p = 0.02). Conclusion: The results show that physicians working in primary health care cannot solely rely on the frequency of antibiotic-treated RTIs as a warning sign for the detection of common humoral immune deficiencies.

Keywords::

• Clinical warning sign
• respiratory tract infections
• immunoglobulin deficiency
• primary health care

Acknowledgments

We wish to thank Jan Ernerudh for valuable advice on immunologic aspects and Mats Nilsson for statistical support and feedback. The study has been funded by grants from FORSS and Futurum, both institutions promoting research in the county of Jönköping.

Declaration of interest: Per Wågström MD, Åsa Nilsdotter MDPhD, and Prof. Janne Björkander are members of the Swedish National Guideline Committee, which is sponsored by Baxter. Prof. Janne Björkander is also a frequent lecturer in educational courses sponsored by Baxter and Octapharma. No other conflicts of interest.