Immunophenotypic analysis of lymphocyte subsets in newborns with biotinidase deficiency

Background/Aim Biotin is a vital micronutrient that plays a role in metabolic homeostasis and the regulation of innate and adaptive immune system functions. Biotinidase deficiency (BTD) leads to impairment in biotin‐dependent immune functions. This study focused on immunophenotypic analysis of lymphocyte subsets in newborns with BTD. Patients and Methods A total of 181 (95 female and 86 male; 114 had BTD and 67 were healthy) newborns underwent biotinidase enzyme activity, molecular and lymphocyte immunophenotyping analyses. BTD is classified into four biochemical phenotypes: profound, partial, heterozygous and normal. The following lymphocyte subsets were studied in all participants: total B lymphocyte (CD19), total T lymphocyte (CD3), helper T lymphocyte (CD3/CD4), cytotoxic T lymphocyte (CTL) (CD3/CD8), natural killer T lymphocyte (CD16/56) and a T‐lymphocyte activation marker (HLA‐DR). Results The percentages of lymphocyte subsets were similar in newborns with and without BTD. In all newborns with BTD, the mean CD3/CD4 levels were higher in females, while the CD3/CD8 levels were higher in males (P