RESUMO
A novel avian influenza A (H7N9) virus recently emerged in the Yangtze River delta and caused diseases, often severe, in over 130 people. This H7N9 virus appeared to infect humans with greater ease than previous avian inlfuenza virus subtypes such as H5N1 and H9N2. While there are other potential explanations for this large number of human infections with an avian influenza virus, we investigated whether a lack of conserved T-cell epitopes between endemic H1N1 and H3N2 inlfuenza viruses and the novel H7N9 virus contributes to this observation. Here we demonstrate that a number of T cell epitopes are conserved between endemic H1N1 and H3N2 viruses and H7N9 virus. Most of these conserved epitopes are from viral internal proteins. The extent of conservation between endemic human seasonal inlfuenza and avian inlfuenza H7N9 was comparable to that with the highly pathogenic avian inlfuenza H5N1. Thus, the ease of inter-species transmission of H7N9 viruses (compared with avian H5N1 viruses) cannot be attributed to the lack of conservation of such T cell epitopes. On the contrary, our ifndings predict signiifcant T-cell based cross-reactions in the human population to the novel H7N9 virus. Our findings also have implications for H7N9 virus vaccine design.
RESUMO
<p><b>OBJECTIVE</b>The Wiskott-Aldrich syndrome (WAS) is a rare X-linked primary immunodeficiency caused by mutations in the WAS protein (WASP) gene. The disease is characterized by recurrent infections, eczema, and thrombocytopenia with small platelets, and it is known to be associated with extensive clinical variability, and mutation studies indicated that genotypes are also highly variant among WAS patients. The present study was conducted to identify the mutation types of Wiskott-Aldrich syndrome protein (WASP) gene in 3 boys suffering from Wiskott-Aldrich syndrome.</p><p><b>METHODS</b>Based on the typical clinical manifestations of Wiskott-Aldrich syndrome including thrombocytopenia, eczema, and recurrent infections and scanning electron micrographs, 3 patients were suspected of having WAS. The WASP gene of the 3 patients and their mothers were detected by PCR-direct sequencing analysis.</p><p><b>RESULTS</b>By sequence analysis using sense and antisense primer separately, the authors found two novel WASP gene mutations. For the twin brothers, a C deletion at nucleotide 984 was detected in exon 10 of WASP gene (984delC). The consequence of the C deletion involved frameshift mutation after H317 and premature stop at 444 (H317fsX444). Their mother was a carrier of the mutated WASP gene. For another WAS patient, a nonsense mutation with nucleotide substitution of G to T at position 1388 (1388G-->T) in exon 11 of WASP gene, led to premature translational termination at amino acid position 452 (E452X). His mother had not been found to have WASP gene mutation.</p><p><b>CONCLUSION</b>Genetic analysis is useful in definite diagnosis of Wiskott-Aldrich syndrome patients and in carrier detection and prenatal diagnosis, especially of atypical or sporadic WAS patients.</p>