BACKGROUND: Recent studies have found that insulin-like growth factors (IGFs) and insulin-like growth factor binding protein-3 (IGFBP-3) have stronger neurotrophic and neuroprotective effects. But whether their levels in cerebrospinal fluid could be used as an auxiliary indicator in differentially diagnosing tuberculous meningitis and viral encephalitis is not yet clear. OBJECTIVE: To explore the changes of insulin-like growth factor-Ⅱ (IGF-Ⅱ) and IGFBP-3 in cerebrospinal fluid (CSF) of children with tuberculous meningitis and the significance of the changes. DESIGN: A non-randomized concurrent controlled study. SETTING: Department of Pediatric Internal Medicine, the First Affiliated Hospital of Xinxiang Medical College. PARTICIPANTS: Thirty children with tuberculous meningitis (14 males and 16 females) were selected from the Department of Pediatric Internal Medicine, the First Affiliated Hospital of Xinxiang Medical College from January 2005 to December 2006. Tuberculous meningitis was diagnosed according to their clinical manifestations, the history of close contact with tuberculosis, typical cerebrospinal fluid changes of tuberculous meningitis, positive tuberculosis antibody and effective antituberculosis treatment. There were 30 children (13 males and 17 females) with viral encephalitis, and viral encephalitis was diagnosed according to epidemiological history, clinical manifestations, conventional and biochemical changes of cerebrospinal fluid, and negative bacteriology judgment. Meanwhile, 30 children (13 males and 17 females) without infectious and central nervous system disease were selected as the control group. Informed consent was obtained from the parents of all the enrolled children. METHODS: ① The lumbar puncture operation was implemented immediately to obtain cerebrospinal fluid (3 mL). The contents of IGF-Ⅱ and IGFBP-3 were detected with immunoradiometric assay. The concentrations of glucose and protein in cerebrospinal fluid were determined with a dry-chemical method. The number of white blood cells was counted by Fushi Method. ② The Pearson correlation analysis was used to analyze the correlation of the contents of IGF-Ⅱ and IGFBP-3 in cerebrospinal fluid with the leucocyte counting and the concentrations of glucose and protein in cerebrospinal fluid. MAIN OUTCOME MEASURES: The contents of IGF-Ⅱ and IGFBP-3 in cerebrospinal fluid, and their correlation with the leucocyte counting and the concentrations of glucose and protein in cerebrospinal fluid. RESULTS: ① Contents of IGF-Ⅱ and IGFBP-3 in cerebrospinal fluid: The contents of IGF-Ⅱ and IGFBP-3 in cerebrospinal fluid in the tuberculous meningitis group were significantly higher than those in the encephalitis virus group and control group (P < 0.05). There was no significant difference in the contents of IGF-Ⅱ and IGFBP-3 in cerebrospinal fluid between the viral encephalitis group and control group (P > 0.05). ② Correlation: The IGF-Ⅱ and IGFBP-3 contents in cerebrospinal fluid were positively correlated with the protein concentration in cerebrospinal fluid (r =0.821, 0.855, P < 0.01), but negatively with the glucose (r =0.742, -0.605, P < 0.01). CONCLUSION: ① IGFs and IGFBPs are involved in the pathophysiological process of tuberculous meningitis, as well as the glucose and protein metabolism in cerebrospinal fluid. ② The IGF-Ⅱ and IGFBP-3 contents in cerebrospinal fluid can be used as the auxiliary indicators to differentially diagnose tuberculous meningitis and viral encephalitis. BACKGROUND: Recent studies have found that insulin-like growth factors (IGFs) and insulin-like growth factor binding protein-3 (IGFBP-3) have stronger neurotrophic and neuroprotective effects. But whether their levels in cerebrospinal fluid could be used as an auxiliary OBJECTIVE: To explore the changes of insulin-like growth factor-II (IGF-II) and IGFBP-3 in cerebrospinal fluid (CSF) of children with tuberculous meningitis and the Significance: the changes. DESIGN: A non-randomized concurrent controlled study. SETTING: Department of Pediatric Internal Medicine, the First Affiliated Hospital of Xinxiang Medical College. PARTICIPANTS: Thirty children with tuberculous meningitis (14 males and 16 females) were selected from the Department of Pediatric Internal Medicine, the First Affiliated Hospital of Xinxiang Medical College from January 2005 to December 2006. Tuberculous meningiti s was diagnosed according to their clinical manifestations, the history of close contact with tuberculosis, typical cerebrospinal fluid changes of tuberculous meningitis, positive tuberculosis antibody and effective antituberculosis treatment. There were 30 children (13 males and 17 females) with viral encephalitis, and viral encephalitis was diagnosed according to epidemiological history, clinical manifestations, conventional and biochemical changes of cerebrospinal fluid, and negative bacteriology judgment. Meanwhile, 30 children (13 males and 17 females) without infectious and central nervous system disease were selected as the control group. METHODS was ① taken from the parents of all the enrolled children. METHODS: ① The lumbar puncture operation was implemented immediately to obtain cerebrospinal fluid (3 mL). The concentrations of IGF-Ⅱ and IGFBP-3 were detected with immunoradiometric assay. The concentrations of glucose and protein in cerebrospinal fluid were determined with adry-chemical method. The number of white blood cells was counted by Fushi Method. ② The Pearson correlation analysis was used to analyze the correlation of the contents of IGF-II and IGFBP-3 in cerebrospinal fluid with the leucocyte counting and the concentrations of glucose and protein in cerebrospinal fluid. MAIN OUTCOME MEASURES: The contents of IGF-II and IGFBP-3 in cerebrospinal fluid, and their correlation with the leucocyte counting and the concentrations of glucose and protein in cerebrospinal fluid. Ⅱ and IGFBP-3 in cerebrospinal fluid: The contents of IGF-Ⅱ and IGFBP-3 in cerebrospinal fluid in the tuberculous meningitis group were significantly higher than those in the encephalitis virus group and control group (P <0.05). There was no significant difference in the contents of IGF-II and IGFBP-3 in cerebrospinal fluid between the viral encephalitis group and control group (P> 0.05) .② Correlation: The IGF-II and IGFBP-3 contents in c erebrospinal fluid were positively correlated with the protein concentration in cerebrospinal fluid (r = 0.821, 0.855, P <0.01), but negatively with the glucose (r = 0.742, -0.605, in the pathophysiological process of tuberculous meningitis, as well as the glucose and protein metabolism in cerebrospinal fluid. ② The IGF-II and IGFBP-3 contents in cerebrospinal fluid can be used as the auxiliary indicators to differentially diagnose tuberculous meningitis and viral encephalitis.