TRIM21 and systemic lupus erythematosus: Anti-Ro/SSA antibodies (anti-Ro/SSA) consist of two fundamental subtypes, i.e., anti-Ro/SSA-52kD and anti-Ro/SSA-60kD, whose detection is frequent in CTDs, particularly Sjögren’s syndrome (30–95%) and SLE (30–50%), but also in 0.5–2.7% of the apparently healthy population (114).