Cytometry by time of flight and type 1 interferon gene analysis revealed unique fingerprints that are indicative of a broad immune landscape shift following CD38 targeting.<h4>Conclusions</h4>Mezagitamab had a favourable safety profile in patients with moderate to severe SLE and elicited a pharmacodynamic effect consistent with CD38+ cell depletion. The gene discussed is CD38; the disease is systemic lupus erythematosus.