D2.293 - Assessment of the Efficacy of Specific Immunotherapy After a Long Break in Asthmatic Patients

Specific immunotherapy (SIT) has been established for over a century. Today, SIT is primarily performed using allergoids as therapeutic allergens. The recommended duration of SIT is typically three years. However, during the COVID-19 pandemic, SIT was paused in many cases. This study analyzes the efficacy of resuming SIT after a pause of at least one year. Specifically, we analyzed the time required to achieve the maintenance dose

: Asthmatic patients who had previously undergone SIT for Dermatophagoides at least one year prior to the break were analyzed. Before resuming SIT, all subjects underwent PRICK tests, as well as measurements of total IgE and specific IgE for Dermatophagoides pteronyssinus. SIT was considered effective if a wheal of at least 5 mm was observed.

The efficacy of SIT for Dermatophagoides pteronyssinus was assessed in 45 asthmatic patients after a one-year break, including 31 females and 14 males. The average age was 38.4 (±16) years. PRICK tests were performed for all patients before resuming SIT. Total IgE and specific IgE against Dermatophagoides were also measured. SIT was continued until a satisfactory wheal response was obtained. The average total IgE before restarting SIT was 346 (±56) IU/ml, and the average specific IgE was 23 (±55) IU. The average time to achieve a satisfactory wheal was 2.9 (±0.4) weeks. The time to reach the maintenance dose was shorter for patients with stronger PRICK test reactions. A shorter time to achieve a satisfactory SIT wheal correlated more strongly with the intensity of the PRICK test response than with the concentration of total or specific IgE. ARQL improved more quickly after restarting SIT compared to the initial SIT course. The average time for ARQL improvement after resuming SIT was 6.3 (±0.7) weeks, compared to 7.7 (±1.1) weeks during the first course.

Resuming SIT after a long break was successful, with a shorter time to achieve improvement in ARQL and the maintenance dose.