LEVELS OF SPECIFIC IGG AND IGE AGAINST BOS D 5 (BOVINE BETA-LACTOGLOBULIN) IN ROUTINE ANALYSES OF ASYMPTOMATIC BRAZILIAN CHILDREN

Background: Specific IgG against Bos d 5 (bovine beta-lactoglobulin - BLG) has been related to immune conditions such as insulin-dependent diabetes mellitus or non-IgE-mediated cow’s milk hypersensitivity. We analyzed the presence of specific-IgG (s-IgG) and specific-IgE (s-IgE) against BLG in routine laboratory exams on a non-selected children population.Methods: The laboratory results of 402 children were retrospectively evaluated, regardless of their diagnosis, during routine laboratory exams to s-IgG and s-IgE against BLG. Two groups were separated according to the occurrence of undetectable (< 0.35 kU/L) s-IgE to BLG (363 children – 90.3%) or detectable s-IgE to BLG (39 children – 9.7%).Results: In the undetectable s-IgE to BLG group, 54% of the children (196/363) had detectable (> 2.0 kU/L) s-IgG to BLG (mean 11.4 kU/L; SD 19.9 kU/L). In the group with detectable s-IgE to BLG (mean 4,2 kU/L; SD 10.1 kU/L), 89% of the children (35/39) had detectable s-IgG against BLG (mean 23.1 kU/L; SD 27.6 kU/L). Excluding the undetectable s-IgG results from the analyses, the non-parametric difference between the median values of s-IgG between the detectable and undetectable s-IgE groups was significant with p = 0.00012 as analyzed by the Mann-Whitney test.Conclusion: The presence of detectable s-IgG against BLG is a common finding in the pediatric population (about 57.2% of all children tested). However, it is more common (89.7%), and the levels are higher in patients with detectable s-IgE against BLG. The isolated research of s-IgG against BLG is not a useful immunoassay to diagnose cow’s milk allergy.