However, we found bimodal expression of the surface SIGLEC-1 among SLE patients, with 10 subjects (10/34, 29%; Fig. 2b) presenting low levels of protein expression, similar to the ranges observed in healthy donors, and the rest presenting much higher levels, rarely observed in healthy volunteers (Fig. 2a, b). Here, SIGLEC1 is linked to systemic lupus erythematosus.