CAMP and systemic lupus erythematosus: LL37 and citrullinated LL37 (cit-LL37) are present in SLE skin/kidney, and SLE T-cells proliferate to both native-LL37 and cit-LL37 in up to 45% of SLE patients, with cit-LL37 being a more efficient T-cell antigen than native-LL37.