C3 and systemic lupus erythematosus: Several reports mention those anti-nucleosome antibodies as a disease activity marker in patients with SLE (52) and even correlate better than other conventional biomarkers (C3/C4 or anti-dsDNA) with SLE disease activity over time (53), making of the measurement of salivary IgA anti-nucleosome an attractive possibility for the routine monitoring of SLE patients in clinical practice due to the easy access and availability of the type of sample contingent on the validation of these observations in larger/multicenter cohorts and the development of specific antibody tests for this purpose.