Anti-cardiolipin, anti-cardiolipin plus bovine, or human β2glycoprotein-I and anti-human β2glycoprotein-I antibodies in a healthy infant population

Background. Pathogenic antiphospholipid antibodies studies are usually conducted on populations of adults. Studies involving normal children are scant. Methods. Antibody reactivity against CL alone (true aCL), CL-complexed to bovine beta(2)GP-1 (aCL-bovine beta(2)GP-I), or human (aCL-human beta(2)GP-I) beta(2)GP-I, or to phospholipidfree human (beta(2)GP-I (anti-human beta(2)GP-I) was determined by ELISA in serum samples from 360 Mexican children ranging from 1 month through 8 years of age. Results. Statistical analysis of variance and rankings of Kruskal-Wallis demonstrated no significant difference in all tested antibody activities between ages and genders of the study population. Values are presented as a percentile distribution included between 5 and 99, corresponding to the percentages of the studied population. Normal arbitrary units (AU) for IgG, IgA, and IBM true aCL that correspond to the 95 and 99 percentiles are as follows: 2.15 and 3.5: 2.35 and 5.0, and 3.15 and 4.5, respectively. IgG. IgA, and IgM aCL-bovine ( beta(2)GP-I activities are 2.6 and 5.0, 3.0 and 5.0, and 2.7 and 6.0 AU, respectively, while IgG activities of aCL-bovine and human beta(2)GP-I are 1.45 and 1.80, respectively. Normal values for IgG anti-human beta(2)GP-I are 1.85 AU. Conclusions. While elevated serum levels of antibodies to CL and/or [beta(2)GP-I have been associated with thrombotic and hematologic manifestations. the majority of reports deal with adult populations. We report the cut-off values (in AU, international PL units, and international units for beta(2)GP-I) of the specific serologic response of true aCL, aCL-bovine beta(2)GP-I, aCL-human beta(2)GP-I, and anti-human beta(2)GP-I in healthy Mexican children. (C) 2002 IMSS. Published by Elsevier Science Inc.