We have not measured C3 and IgG on MPs derived from the NHDs and SLE patients included in this study, but we have in our unit previously examined the composition of MPs from healthy donors and SLE patients using the same MP purification technique: We found that MPs from SLE patients had increased amounts of C3 fragments and IgG on the surface [19, 23], and increased deposition of complement on MPs has been associated with disease activity [33]. Here, C3 is linked to systemic lupus erythematosus.