CALR and systemic lupus erythematosus: Among serologic factors, the presence of anti-Ro has been associated with lower bone mass because anti-Ro positive SLE patients are usually advised against sun exposure, while presence of anti-Sm has been associated with higher BMD of the hip; the presence of antibodies against citrullinated protein (ACPA) or anti-carbamylated protein antibodies (antiCarP) in a small subgroup of SLE patients with erosive arthritis has been associated with significant bone loss, as it occurs in patients with rheumatoid arthritis [16,21].