Anticardiolipin and anti-beta(2)glycoprotein-I antibodies in patients withsystemic lupus erythematosus: Comparison between Colombians and Spaniards

We studied the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-beta(2)glycoprotein I (anti-beta(2)GPI) a ntibodies in two populations of patients with systemic lupus erythematosus (SLE), 160 Colombians and 160 Spaniards. All sera were tested in our labora tory by enzyme-linked immunosorbent assay (ELISA) for IgG, IgM, and IgA aCL , as well as IgG and IgM anti-beta(2)GPI. Positive results for at least 1 o f the 3 aCL isotypes were found in 40 Colombians (25%) and 55 Spaniards (34 %). IgG aCL was the predominant isotype in both populations. Positive resul ts for at least 1 of the anti-beta(2)GPI isotypes were found in 34 Colombia ns (21%) and 29 Spaniards (18%). IgG anti-beta(2)GPI was the dominant isoty pe in Colombians, while IgM was predominant in Spaniards. Positivity for an ti-beta(2)GPI in aCL-positive patients was present in 77% in the Colombian group and 50% in the Spaniard group. Among Colombians, IgG aCL and anti-bet a(2)GPI correlated with thrombosis, fetal loss, and thrombocytopenia. Among Spaniards, IgG aCL and IgG anti-beta(2)GPI correlated with thrombosis, fet al loss, and livedo reticularis. For detecting thrombosis and fetal loss, a CL ELISA was more sensitive than anti-beta(2)GPI in Spaniards, and anli-bet a(2)GPI ELISA was more specific than aCL in both populations.