Clinical And Immunological Characterization Of ISG Mutation In A Chinese Family And Immunological Study Of C?TA Mutated MHC? Deficiency Disease

PART ? CLINICAL AND IMMUNOLOGICAL CHARACTERIZATION OF ISG MUTATION IN A CHINESE FAMILYObject: To investigate the clinical and immunological characterization of 2 cases with a homozygous novel mutation in ISG15 gene from a consanguineous Chinese family.Methods: We investigated the clinical and immunological features of the two patients,analyzed genetic variation of ISG15 gene by whole exome sequencing and Sanger sequencing,detected ISG15 protein expression in neutrophils by flow cytometry and immunofluorescence,measured lymphocyte subsets and their proliferation by flow cytometry,tested productions of NADPH-oxidase-mediated reactive oxygen species(ROS)in neutrophils by Luminol-amplified chemiluminescence.Results: Patient One,a nearly 2-years-old male,presented with recurrent respiratory infection.Patient Two,a 3-months-old female,showed recurrent systemic skin suppurative infection.The lymphocyte subsets frequency,absolute number,TCR repertoire and proliferation function were normal.IFN-?-IL12 axis function was normal.Homozygous mutations c.420C>A(p.Y140X)on Exon 2 from their heterozygous parents result in absence of ISG15 protein expression in neutrophils.Productions of extracellular NADPH-oxidase-mediated reactive oxygen species(ROS)induced by PMA,fMLP and WKYMVM in neutrophils were significantly impaired.While the productions of intracellular NADPH-oxidase-mediated ROS in neutrophil was normal.Conclusion: We firstly describe two patients from the same family with novel ISG15 mutation causing ubiquitin-like domain truncation The patients manifest new clinical phenotype of recurrent pulmonary and cutaneous bacterial infection,which indicates the clinical heterogeneity of ISG15 defect.Truncated ubiquitin-like motif of ISG15 may be related to the disturbance of extracellular NADPH-oxidase-mediated ROS produced by neutrophils resulting in recurrent bacterial infection.PART ? IMMUNOLOGICAL STUDY OF C?TA MUTATED MHC? DEFICIENCY DISEASEObject: To investigate the clinical and molecular characterization of a case of C?TA mutated MHC? deficiency disease.Methods: we investigated the clinical features,genetic variation of C?TA gene and the HLA-DR expression in a 2 years-old male patient with recurrent diarrhea,respiratory infection,persistent CMV infection,BCG disease and severe malnutrition.Results: Immunological analysis revealed the reduced frequency of CD4+ T cells in the periphery with inverted CD4/CD8 ratio and hypogammaglobulinemia.Compound heterozygous mutations in C ? TA were detected by Sanger sequencing showing a paternal mutation c.3223C>T and a novel maternal mutation c.1240 del C resulting in absence of HLA-DR expression in CD19+ B cells and CD14+ monocytes.And the functions of T cells were leaky impaired.Conclusion: A Chinese patient with novel maternal mutation in C?TA was diagnosed by analysis of clinical and Immunological features,gene sequencing and protein analysis.Hematopoietic stem cell transplantation is still the only radical method but with a lower success rate comparing with other combine immunodeficiency.