TRIM21 and systemic lupus erythematosus: Two mouse monoclonals and 1 rabbit polyclonal antibody to Ro52, in which the target epitopes are not disclosed (Figure 1, D–F), reproduced identical patterns of Ro52 detected in neutrophils and PBMCs by SLE serum (Figure 1C), including some additional bands of approximately 27–33 kDa found in neutrophils.