Background: Whole saliva is increasingly used as a diagnostic tool for various conditions. The
collection is noninvasive and therefore especially attractive in epidemiological studies
of children. We reviewed published evidence of the use of diagnostic salivary biomarkers
for systemic inflammatory and allergic conditions among children and adolescents to
evaluate their diagnostic potential in studies of children. Methods: We performed a systematic search of relevant publications in the MEDLINE database
using a combination of key words (such as „atopy“, „allergy“, „infection“, „inflammation“,
„saliva“ and „analysis“). We also checked the reference lists of the retrieved articles.
We included every study that fulfilled these criteria: an allergic or inflammatory
target condition; a sample size greater than 20 participants; an age range of 4 to
20 years; and a gold standard test or a reference diagnosis. Results: Twenty four studies met our inclusion criteria, eight of which had target allergic
conditions (asthma, allergic rhinitis, eczema) and sixteen had target inflammatory
conditions such as specific infections. Nine were case control studies, twelve were
population based cross sectional studies, and three were cohort studies. The participant
numbers ranged from n=20 to 995. Salivary IgG or IgM to viral and bacterial antigens
(e.g. rubella, measles, dengue, Helicobacter pylori, Bordetella pertussis) exhibited
a fairly good validity compared to serum antibodies or other reference tests. The
test performances did not vary with age but were slightly affected by salivary collection
and analysis methods. Nevertheless, validity for the investigated atopy markers like
salivary IgA was not consistent, although children with allergic conditions tended
to have lower secretory IgA levels than healthy ones. Conclusions: Saliva in children can be used as a diagnostic tool for acute and past exposure to
specific infections and to determine immunity, but the existing literature shows no
evidence for potentially valid biomarkers for atopy.
