Anticardiolipin and anti-β2glycoprotein-I antibodies in patients with systemic lupus erythematosus: Comparison between Colombians and Spaniards

We studied the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-β2glycoprotein I (anti-β2) antibodies in two populations of patients with systemic lupus erythematosus (SLE), 160 Colombians and 160 Spaniards. All sera were tested in our laboratory by enzyme-linked immunosorbent assay (ELISA) for IgG, IgM, and IgA aCL, as well as IgG and IgM anti-β2GPI. Positive results for at least 1 of the 3 aCL isotypes were found in 40 Colombians (25%) and 55 Spaniards (34%). IgG aCL was the predominant isotype in both populations. Positive results for at least 1 of the anti-β2GPI isotypes were found in 34 Colombians (21%) and 29 Spaniards (18%). IgG anti-β2GPI was the dominant isotype in Colombians, while IgM was predominant in Spaniards. Positivity for anti-β2GPI in aCL-positive patients was present in 77% in the Colombian group and 50% in the Spaniard group. Among Colombians, IgG aCL and anti-β2GPI correlated with thrombosis, fetal loss, and thrombocytopenia. Among Spaniar...