Ames PRJ, Batuca JR, Ciampa A, Iannaccone L, Delgado Alves J. Clinical relevance of nitric oxide metabolites and nitrative stress in thrombotic primary antiphospholipid syndrome. J Rheumatol 2010;37:2523-30. Table 2, under the heading “Predictors”: “Arterial” should be “Arterial thrombosis”. We regret the error.