The changes of serum Blomia tropicalis antibody levels in patients with Dermatophagoides pteronyssinus immunotherapy: the effect of synergistic therapyAbstractBackground: Dermatophagoides pteronyssinus (Der p) allergen-specific immunotherapy (AIT) may affect the expression of Blomia tropicalis (Blo t) sIgE in patients’ serum. This study was aim to analyze the changes and relationships between Der p and Blo t sIgE, Der p and Blo t sIgG4 in asthma patients with rhinitis (AS+AR) during the Der p AIT, and to explore the expression of Blo t antibody and the synergistic therapeutic effect in Der p AIT.Method: 34 patients with Der p sensitized AS+AR were tested Der p and Blo t sIgE, sIgG4 on four time points: AIT before treatment (0Y), treatment for half a year (0.5Y), 1 year (1Y), 2 years (2Y) and 3 years (3Y) , respectively.Result: After 3Y Der p AIT, 61.8% patients tIgE concentrations increased, 64.7% Blo t sIgE increased, and 87.9% Blo t sIgG4 increased. In 0.5Y, serum Der p and Blo t sIgE levels were significantly increased and maintained, and tIgE levels also increased significantly in 0.5Y and 1Y, but decreased in 2Y. With the AIT time increased, Der p and Blo t sIgG4 gradually increased. In addition, Blo t and Der p sIgE were significantly associated with Blo t and Der p sIgG4 during the three-year treatment. The optimal scale analysis showed that with the AIT time increased, Blo t sIgG4 and sIgE was more strongly associated with Der p sIgG4 and sIgE.Conclusion: The levels of serum Der p and Blo t sIgE, and sIgG4 increased during Der p AIT. Der p may induce the production of Blo t sIgG4, and Der p sIgG4 may antagonize Blo t sIgE. Thus, Der p AIT may also effective against Blo t allergic reactions.Key words: Asthma, Blo t, sIgE, sIgG4, AIT