title: Relationship of aging and nutritional status to innate immunity in tube-fed bedridden patients.
abstract: OBJECTIVE
  Aging and malnutrition are known to influence immune functions. The aim of this study was to investigate the relationship of aging and malnutrition to innate immune functions in tube-fed bedridden patients.
  
  
  METHODS
  A cross-sectional survey was performed in 71 tube-fed bedridden patients aged 50-95 years (mean age±SD, 80.2±8.5 years) with serum albumin concentrations between 2.5 and 3.5 g/dL. We evaluated associations of age and nutritional variables with natural-killer cell activity, neutrophilphagocytic activity, and neutrophil-sterilizing activity. Nutritional variables included body mass index, weightadjusted energy intake, total lymphocyte count, and serum concentrations of albumin, transferrin, prealbumin, total cholesterol, C-reactive protein, and zinc.
  
  
  RESULTS
  Natural-killer cell activity, neutrophil-phagocytic activity, and neutrophil-sterilizing activity were normal or increased in 67 (94%), 63 (89%), and 69 (97%) patients, respectively. Multiple linear regression analysis with a backward elimination method showed that natural-killer cell activity correlated negatively with aging and lymphocyte counts (p<0.01 for both) but positively with body mass index and transferrin (p<0.01 for both). Neutrophil-phagocytic and neutrophil-sterilizing activities were not associated with any variables.
  
  
  CONCLUSIONS
  In tube-fed bedridden patients with hypo-albuminemia, natural-killer cell activity may be associated with aging, body mass index, transferrin, and lymphocyte counts.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan. Email: yoshtake@med.showa-u.ac.jp.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Takeuchi
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan.
authors.forename: Tomoe
authors.initials: T
authors.lastname: Tashiro
authors.affiliation: Department of Gastroenterological Surgery, Sangenjaya Dai-ichi Hospital, Setagaya-ku, Tokyo, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamamura
authors.affiliation: Department of Internal Medicine, Fuji-Yoshida Municipal Hospital, Fuji-Yoshida, Yamanashi, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Gastroenterology, Ohta-Atami Hospital, Koriyama, Fukushima, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Katayose
authors.affiliation: Department of Internal Medicine, Kohga Hospital, Yaidu, Shizuoka, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Kohga
authors.affiliation: Nutritional Science Institute, Morinaga Milk Industry Co., Ltd, Zama, Kanagawa, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Takase
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Imawari
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D002149:Energy Intake; D004750:Enteral Nutrition; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000276:immunology; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology; D009752:Nutritional Status / Q000276:immunology*; D010586:Phagocytes / Q000276:immunology; D012709:Serum Albumin / Q000032:analysis; D014168:Transferrin / Q000032:analysis
chemical_list: D012709:Serum Albumin; D014168:Transferrin