Indeed, while supernatants from CD3 and CD3+CD46‐activated (after 36 h) HC T cells contained ∼2 and ∼8 ng/mL sCD46, respectively, SLE T cells ‘produced’ ∼50 ng/mL sCD46 with CD3 activation and up to ∼300 ng/mL after CD3+CD46 stimulation (Fig. 4C). Here, CD46 is linked to systemic lupus erythematosus.