[Relationship between variation of coxsackievirus B3 VP1 sequence from cerebrospinal fluid of children and severity of damage to central nervous system].

OBJECTIVE:To investigate the possible relationship between variation of coxsackievirus B3 (CoxB3) VP1 sequence from cerebrospinal fluid of children with severe and mild central nervous system (CNS) infection and damage to CNS in children from Shandong province. METHODS:The enteroviruses were detected using VP1 typing and sequencing primer for enteroviruses from 73 enterovirus-infected cases confirmed by detection of cerebrospinal fluid by enteroviruses common primer. VP1 sequences (450 nucleotides) were determined and analyzed for 21 CoxB3 enteroviruses strains isolated in Qingdao and Binzhou, and were compared with that of BLAST search procedures from GeneBank in NCBI. The variation of VP1 gene and amino acids sequence of CoxB3 enteroviruses was analyzed for severe and mild CNS infection. RESULTS:The nucleotide homogeneity of these CoxB3 appeared to be 97% - 99%, however, the homogeneity among different genotypes were 83% - 76%. Replacement of glutamine by histidine at amino acid locus 856 of VP1 CoxB3 was found in 4 cases with severe encephalitis. There were different variation in VP1 nucleotide sequence of CoxB3 in 3 cases with mild encephalitis and 14 cases with meningitis, but amino acids sequences had no regular variation. The modified Glasgow's coma score was below 7 in all the 4 cases with severe encephalitis. Of these 4 cases, 3 had consciousness disturbance for less than 3 days. Lethargy, restlessness and psychiatric symptoms were major manifestations, of whom 3 also had dysphagia, 1 had encephalatrophy obviously, Glasgow's coma score was 3, deep coma lasted for 9 days, and had concomitant fatal epileptic attacks. Of these 4 cases, 2 completely recovered, 1 had high muscle tone, 1 remained under anti-epileptic drug treatment at follow-up 6 months later. CONCLUSION:There were a small epidemic of CoxB3 CNS infection in children in 2005 in this area. The amino acid variation of CoxB3 VP1 possibly caused increased viral virulence and caused damage to CNS.