Characterizing Systemic Reactions During Subcutaneous Immunotherapy for House Dust Mite Allergies in China: Insights...

Subcutaneous immunotherapy (SCIT) can trigger systemic reactions (SRs) that pose potential life-threatening risks. To date, no cluster analysis has been conducted to delineate sub-phenotypes of SRs. This study aims to identify and characterize diverse SR phenotypes during SCIT for house dust mite (HDM) allergies in China.

This large retrospective real-world study enrolled patients diagnosed with HDM-sensitized allergic rhinitis (AR) and/or asthma who underwent SCIT (Alutard SQ; ALK) between February 2013 and July 2024 at five allergy centers in China. Data on demographic profiles and SRs were collected, followed by a cluster analysis among SR patients.

A total of 3,126 patients received 107,588 injections, with SRs observed in 354 patients (11.32%) and 1,056 injections (0.98%). A higher incidence of SRs was noted in younger patients (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.88-0.92; P < 0.001), those with asthma (OR, 2.12; 95% CI, 1.69-2.66; P < 0.001), those with longer disease duration (OR, 1.08; 95% CI, 1.04-1.12; P < 0.001), those with high sensitization (OR, 3.84; 95% CI, 1.66-8.88; P = 0.002), and those with polysensitization (OR, 1.69; 95% CI, 1.30-2.20; P < 0.001). Four distinct clusters of SRs were identified: Cluster 1 (16.5%) primarily comprised relatively older females with lower specific immunoglobulin E (sIgE) levels, predominantly cutaneous involvement, fewer SRs overall but with grade 4 SR; Cluster 2 (29.9%) mainly included AR patients without asthma, mostly exhibiting grade 1 SR; Cluster 3 (34.0%) predominantly consisted of asthma patients with monosensitization, higher injection doses, and mostly grade 2 SR; Cluster 4 (19.6%) mainly featured younger males with higher sIgE levels, polysensitization, lower injection doses, the highest number of SRs, and more grade 3 SR.

Asthma, disease duration, high sensitization, and polysensitization emerge as independent risk factors for SRs. Our cluster analysis delineates distinct clinical phenotypes of SRs, offering tailored interventions for the personalized management of patients experiencing SRs.