Box-and-whisker plots of autoantibodies binding to cardiolipin (CL) and its derivatives. Median, quartiles, range, and possibly extreme values are shown. NHS indicates healthy donors. (a) anticardiolipin reactivity; (b) antimonolysocardiolipin reactivity; (c) antidilysocardiolipin reactivity; (d) antihydrocardiolipin reactivity. The average immunoreactivities to CL and monolysocardiolipin were significantly higher than those for dilysocardiolipin and hydrocardiolipin, both in antiphospholipid syndrome (APS) (P < 0.0001) and systemic lupus erythematosus (SLE) patients (P < 0.001) (a, b). aCL, anticardiolipin antibody; aDCL, antidilysocardiolipin antibody; aHCL, antihydrocardiolipin antibody; aMCL, antimonolysocardiolipin antibody; OD, optical density.