title: Relation of serum retinol to acute phase proteins and malarial morbidity in Papua New Guinea children.
abstract: BACKGROUND
  Acute phase proteins (APPs) are associated with malaria-induced hyporetinemia (serum retinol <0.70 micromol/L); however, the degree of the association is not well documented.
  
  
  OBJECTIVE
  The association between malaria-induced hyporetinemia and APPs was assessed.
  
  
  METHODS
  In a cross-sectional study, 90 children with serum retinol concentrations from <0.35 to >1.05 micromol/L were selected from children in a clinical trial of vitamin A supplementation. Serum was collected before treatment allocation. Retinol binding protein (RBP) concentrations were determined by radioimmunoassays, and transthyretin, alpha(1)-acid glycoprotein (AGP), alpha(1)-antichymotrypsin, C-reactive protein (CRP), haptoglobin, and albumin concentrations by radial immunodiffusion assays.
  
  
  RESULTS
  Children in the subsample had high rates of splenomegaly and Plasmodium-positive blood-smear slides (P < 0.01); AGP (Pearson's r = -0.40, P < 0.001) and CRP (r = -0.21, P = 0.04) were inversely correlated with retinol. The negative APPs RBP, transthyretin, and albumin were positively and significantly associated with retinol. All APPs, except alpha(1)-antichymotrypsin, were significantly correlated with splenomegaly. Of the positive APPs, AGP correlated with CRP (r = 0.37, P < 0.001), indicating chronic inflammation. In a stepwise regression analysis, 73% of retinol's variability was explained by RBP and transthyretin. The model predicted that a 1-SD increase in RBP or transthyretin increases retinol by approximately 0.38 or 0.47 micromol/L, respectively, whereas an equivalent increase in AGP decreases retinol by 0.12 micromol/L.
  
  
  CONCLUSIONS
  The RBP-transthyretin transport complex of retinol is not altered by inflammation. Positive APPs are useful markers of type and severity of inflammation; however, except for AGP, it is unlikely that they can correct for malaria-induced hyporetinemia.
authors.affiliation: Nutrition and Veterinary Science Departments, The Pennsylvania State University, University Park, PA 16802, USA. fxr5@psu.edu
authors.forename: F J
authors.initials: FJ
authors.lastname: Rosales
authors.forename: J D
authors.initials: JD
authors.lastname: Topping
authors.forename: J E
authors.initials: JE
authors.lastname: Smith
authors.forename: A H
authors.initials: AH
authors.lastname: Shankar
authors.forename: A C
authors.initials: AC
authors.lastname: Ross
mesh_terms: D000209:Acute-Phase Proteins / Q000032:analysis*; D000818:Animals; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D008297:Male; D009017:Morbidity; D010219:Papua New Guinea / Q000453:epidemiology; D010963:Plasmodium falciparum / Q000302:isolation & purification; D011228:Prealbumin / Q000032:analysis; D012177:Retinol-Binding Proteins / Q000032:analysis; D013163:Splenomegaly; D014801:Vitamin A / Q000097:blood*; D014802:Vitamin A Deficiency / Q000209:etiology
chemical_list: D000209:Acute-Phase Proteins; D011228:Prealbumin; D012177:Retinol-Binding Proteins; D014801:Vitamin A