C3 and systemic lupus erythematosus: High antibody titers against double-stranded DNA (anti-dsDNA) coupled with low levels of C3 and C4 advocate activity of SLE, although thrombocytopenia itself has not been found to be associated with anti-dsDNA.11 On the other hand low levels of C3 or CH50 has been associated with thrombocytopenia.12