096 IL23-induced STAT3 nuclear translocation in MAIT cells at baseline is a candidate biomarker of response to biologics targeting the IL23/IL17 axis

The role of the interleukin (IL)23/IL17 axis in psoriasis is well-established and has led to development biologics targeting IL23 IL17A. Ustekinumab, targets IL12/23p40 shared subunit blocks IL23-receptor interactions, restricting activation Signal Transducer Activator Transcription 3 (STAT3) T cells, IL17A production. Secukinumab binding its receptor, preventing keratinocyte activation. Although both are effective, clinical response varies, highlighting need identify biomarkers predictive response. To IL23/IL17 axis, we first measured IL23-induced STAT3 translocation peripheral blood mononuclear cells (PBMCs) patients (n=20) before (week (W)0) during (W1, W4 W12) ustekinumab therapy. Clinical was assessed by 75% reduction Psoriasis Area Severity Index (PASI75) at W12. mucosal associated invariant (MAIT) PASI75 non-responders significantly lower (p<0.05, FDR<0.05) than responders W0 highly outcome Receiver Operating Characteristic (ROC) curve analysis. Next, prior therapy with anti-TNF adalimumab (n=10) or secukinumab (n=10). We observed no difference between responders. However, (p<0.05) MAIT compared W0. Ongoing work aimed refining this signal deep-immunophenotyping IL23-responsive undergoing biologic treatment. Taken together, have identified as a candidate biomarker axis.