Here are some research papers you can share:
Long-lasting effects of sublingual immunotherapy according to its duration: a 15-year prospective study https://pubmed.ncbi.nlm.nih.gov/20934206/
Efficacy and Safety of Subcutaneous and Sublingual Immunotherapy for Allergic Rhinoconjunctivitis and Asthma https://pubmed.ncbi.nlm.nih.gov/28964530/
Clinical improvement after escalation for sublingual immunotherapy (SLIT) https://pubmed.ncbi.nlm.nih.gov/21938688/