title: Certain immune markers are not good indicators of mild to moderate biotin deficiency in rats.
abstract: To assess the effects of marginal biotin deficiency on immune function and thereby evaluate immune function as a potential marker for impaired biotin status, we investigated immune function in a rat model during progression from sufficiency to moderate biotin deficiency. As immune function indicators, we assessed the IgG response to a vaccine and the cytokine responses and relative proportions of lymphocyte subpopulations in the immunocytes in blood, spleen and thymus. Neither phenotype nor organ redistribution of lymphocytes differed between biotin-deficient and biotin-sufficient rats. Assessment of immune function by mitogen T cell proliferation, mitogen-induced interferon-gamma and interleukin-4 levels, IgG antibody responses and natural killer cell activity were not significantly different in mild to moderately biotin-deficient rats compared with biotin-sufficient controls. The absence of effects on immune function was not attributable to failure to induce biotin deficiency; the rats exhibited unequivocal evidence of biotin deficiency, including reduced hepatic biotin and impaired leucine metabolism resulting from deficiency of the biotin-dependent enzyme methylcrotonyl-CoA carboxylase. We conclude that the immune markers examined are not promising candidates as indicators of mild to moderate deficiency in humans.
authors.affiliation: Arkansas Children's Hospital Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Helm
authors.forename: N I
authors.initials: NI
authors.lastname: Mock
authors.forename: P
authors.initials: P
authors.lastname: Simpson
authors.forename: D M
authors.initials: DM
authors.lastname: Mock
mesh_terms: D000818:Animals; D015415:Biomarkers; D001710:Biotin / Q000032:analysis / Q000172:deficiency*; D019735:Carbon-Carbon Ligases / Q000378:metabolism; D002455:Cell Division; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D018073:Haemophilus Vaccines / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000032:analysis; D015847:Interleukin-4 / Q000032:analysis; D007694:Killer Cells, Natural / Q000276:immunology; D007963:Leukocytes, Mononuclear; D008099:Liver / Q000737:chemistry; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000166:cytology; D013950:Thymus Gland / Q000166:cytology; D014631:Valerates / Q000652:urine
chemical_list: D015415:Biomarkers; D016207:Cytokines; D018073:Haemophilus Vaccines; D007074:Immunoglobulin G; D014631:Valerates; D015847:Interleukin-4; C004961:beta-hydroxyisovaleric acid; D001710:Biotin; D007371:Interferon-gamma; D019735:Carbon-Carbon Ligases; C021573:methylcrotonoyl-CoA carboxylase