Longitudinal profiles of serum specific IgE and IgG4 to Dermatophagoides pteronyssinus allergen and its major components during allergen immunotherapy in a cohort of southern Chinese children

• Allergy immunotherapy (AIT) is the only treatment that offers disease-modifying effects.
• Der p 1 sIgE/sIgG4 ratio is useful to monitor HDM atopy during AIT.
• Younger children may have greater increase in protective sIgG4.
• AIT given earlier may result in better therapeutic outcomes than later.

Longitudinal data on serum specific sIgE and sIgG4 to allergen component of Dermatophagoides pteronyssinus (Der p) during allergen immunotherapy (AIT) are limited in Chinese populations. We serially followed up serum sIgE and sIgG4 to Der p and its components (Der p 1 and 2) in 51 Der p-sensitized children receiving guideline-based medications alone and additional 36-month AIT. The the Der p 1 and Der p 2 sIgE levels were elevated at 6 months and progressively declined from 12 months; the sIgG4 levels for Der p, Der p 1 and Der p 2 were increasing during the first year and reached a plateau thereafter; the sIgE/sIgG4 ratios for Der p 1 and Der p 2 decreased continuously from 6 through 24 months of AIT. Subgroup analysis showed that younger children (≤8 years) experienced a greater increase in sIgG4 levels for Der p, Der p 1 and Der p 2 during AIT compared with older children (9–16 years). In summary, sIgE and sIgG4 to Der p 1 and Der p 2 may be more useful than those to Der p in reflecting the change in immunological reactivity during AIT. Earlier delivery of AIT may yield greater increase in sIgG4 after 36-month treatment than given later in life.