T lymphopaenia in relation to body mass index and TNF-alpha in human obesity: adequate weight reduction can be corrective

• Published in: Clinical endocrinology (Oxford) Vol. 54; no. 3; pp. 347 - 354
• Main Authors: Tanaka, S.-I., Isoda, F., Ishihara, Y., Kimura, M., Yamakawa, T.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01.03.2001
• Subjects: Adult; Aged; Biological and medical sciences; Case-Control Studies; CD4-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - immunology; Etanercept; Female; Humans; Immunoglobulin G - blood; Lymphocyte Count; Lymphopenia - immunology; Male; Medical sciences; Metabolic diseases; Middle Aged; Obesity; Obesity - immunology; Obesity - therapy; Receptors, Antigen, T-Cell, alpha-beta; Receptors, Tumor Necrosis Factor - blood; Regression Analysis; T-Lymphocytes - immunology; Tumor Necrosis Factor-alpha - analysis; Tumor Necrosis Factor-alpha - biosynthesis; Weight Loss; Human; Obesity; Leukopenia; Treatment efficiency; Cytokine; Nutrition disorder; Weight loss; Hemopathy; Very low calorie diet; Blood plasma; Infection; Body mass index; T-Lymphocyte; Adult; Complication; Elderly; Nutritional status; Tumor necrosis factor α; Lymphocytopenia
• ISSN: 0300-0664; 1365-2265
• DOI: 10.1046/j.1365-2265.2001.1139/cn2155.x

Although individuals with obesity are susceptible to infection, the underlying causes have not been fully identified. To investigate whether obesity affects immunity, we studied subjects with isolated obesity. Thirty-four obese persons from our outpatient obesity clinic and 50 nonobese healthy control subjects were studied. The effects of weight reduction were evaluated in obese subjects on a very-low-energy diet. We examined blastogenic response, lymphocyte subsets, circulatory TNF-alpha, soluble TNF-alpha receptor 1, soluble TNF-alpha receptor 2, and in vitro TNF-alpha production in obesity. Lymphocyte subsets were analysed with flowcytometry. TNF-alpha and soluble TNF receptors levels were assayed using commercially available enzyme-linked immunosorbent assay kits. Blastogenic responses to phytohemagglutinin or concanavalin A of T cells, CD3(+), CD4(+), CD8(+), CD4(+)CD45RO(+), and TCR alpha beta T cells were significantly diminished in obese subjects. Strong negative correlations were observed between TCR alpha beta and body weight and BMI in obese subjects. Circulatory levels of TNF-alpha, soluble TNF-alpha receptors, and in vitro TNF-alpha production were significantly increased compared to nonobese subjects. In obese subjects, there were significant positive correlations between serum levels of TNF-alpha and waist-hip ratio, serum levels of soluble TNF-alpha receptor 1 and body weight, soluble TNF-alpha receptor 2 and BMI, and soluble TNF-alpha receptor 2 and waist-hip ratio. The T cell responses and previously reduced non-CD8 T cell subsets were increased significantly following weight reduction. Our results suggest that subsets of T cell populations and their function may be reduced in human obesity, and that this may be related, at least in part, to the elevated TNF-alpha production. Furthermore, this T cell dysfunction can be recovered by adequate weight reduction.