Serum IL-4 as a marker of immunological response to sublingual immunotherapy.

Allergic rhinitis (AR) is characterized by a Th2 polarized immune response. Specific Immunotherapy modifies this bias restoring a physiologic Th1 profile. Sublingual immunotherapy (SLIT) is widely prescribed, but there is no early, simple marker of response. This study was undertaken in order to determine whether serum IL-4 might be a possible marker of SLIT immunological response in order to quickly and easily detect responder patients. Thirty-nine AR patients with a pollen allergy assumed preseasonal SLIT for 3 months. VAS for symptoms and medication efficacy were evaluated. Serum IL-4 was assessed before and 3 and 6 months after SLIT initiation. Eighty-two percent of patients (32/39) showed a clinical response to SLIT. Serum IL-4 significantly decreased at 6 months post-therapy in responders, whereas it increased in non-responders. In conclusion, these results may be considered clinically relevant proof that SLIT treatment induces a quick reduction in Th2 polarization. Serum IL-4 appears to be an early marker of immunological response to SLIT.