Biomarkers in diagnosis of allergic rhinitis
With deeper insights into mechanisms of AR, novel biomarkers have
recently been identified in its diagnosis. Furthermore, several immune
cells and mediators, genes and metabolites have been studied to explore
their potential utilization in diagnosis of AR.
Immune cells andmediators
Several potential immune cells (granulocytes, lymphocytes, etc.) and
mediators might serve as diagnostic biomarkers of
AR.14,76 Izuhara and colleagues have reported that
induction and increased expression of periostin reflect type 2
inflammation and remodelling, and could be regarded as an emerging
biomarker for allergic diseases.77 One study has
demonstrated that allergen-induced surface CD203c expression on
basophils exhibits a time-of-day-dependent variation, and
allergen-specific basophil reactivity shows daily variations depending
on circadian clock activity in basophils, which could partly be
responsible for temporal symptomatic variations in
AR.78 One recent study has suggested that circulating
group 2 innate lymphoid cells (ILC2s) may play an important role in the
pathology of AR, particularly as increased levels of ILC2scorrelated
with symptom scores and IL-13 levels in house dust mite (HDM)-sensitized
AR patients,79 and these cells produce large amounts
of proinflammatory mediators in response to Th2
cytokines.80,81 Indeed, a more recent study by Tojima
and colleagues found that prostaglandin D2 (PGD2) and cysteinyl
leukotriene (cysLTs) might induce ILC2s to produce Th2 cytokines such as
IL-5 and IL-13.82 Similarly, ST2-expressing
pathogenic memory T helper (Th) 2
cells, producing substantial amounts of IL-33-induced IL-5 and IL-13,
have been shown to be linked to sensitization and the onset and
progression of AR (Figure 3).83