The Prenatal Diagnosis Of Different Types Of Rare Severe Combined Immunodeficiency Diseases And The Immunological Study Of ZAP70 Deficiency Disease

PART I THE PRENATAL DIAGNOSIS OF DIFFERENT TYPES OF RARE SEVERE COMBINED IMMUNODEFICIENCY DISEASESObjective: To investigate the prenatal diagnostic methods and analyze the results in different types of rare severe combined immunodeficiency diseases(SCID).Methods: Five high-risk fetus were from four unrelated families,which had finished prenatal diagnosis in Children's Hospital of Chongqing Medical University at 2016-2017,as the research subjects.We made a retrospective analysis of amniotic fluid exfoliative cells,umbilical cord blood cells and the newborn' gene validation,and did immunological function assessment after birth,including lymphocyte count,TCRV? spectratyping,TREC quantitative PCR test and T lymphocytes' proliferation.Results:(1)The four families had IL-2RG mutations(family 1: c.562C>T,p.Q188X;family 2: c.725G>A,p.W237X),RAG1 mutations(family 3: c.2168C>T,p.A723V;c.2275C>T,p.R759C;c.3020A>G,p.N1007S)and IL-7R? mutations(family 4: IVS4+1G>A;c.638C>T,p.R206X),one or both parents were carriers;(2)After amniotic fluid cytology gene detection,three cases of five high-risk fetus were normal genotypes,one was carrier,and the other was mutated patient;(3)three cases of high-risk infants who had the normal genotypes were healthy after birth by now,one case with maternal mutation did the umbilical cord blood for further examination and postnatal gene validation and immunological function assessment,showed normal results which are consistent with the gene of amniotic fluid exfoliative cells.Conclusions: The gene detection of amniotic fluid exfoliated cells is a relatively accurate method in prenatal diagnosis of SCID,but when a family with the compound heterozygous mutations,an umbilical cord blood cell test should be carried out,to except the maternal tissue contamination in amniotic fluid.While X-linked disease,gennder identification is of assistance for warrantee disease free baby.All high-risk fetus should be validated with gene rechecking and immunological function after birth,so as to ensure the accuracy of the prenatal diagnosis.PART II CLINICAL AND IMMUNOLOGICAL CHARACTERIZATION OF ZAP70 DEFICIENCY DISEASEObjective: We describe in detail the first case from China with novel compound heterozygous mutations in ZAP70 to extend the phenotype spectrum of ZAP70 deficiency.Methods: The patient was a seven-month-old boy with recurrent infection admitted to Children's Hospital of Chongqing Medical University in June 2016.Peripheral blood mononuclear cells(PBMCs)were collected and lymphocyte subsets were analysed.Function analysis of T cells was also conducted.Results: The patient suffered from early-onset and recurrent infections,but showed normal growth and development without sign of failure to thrive,presented as leaky SCID.The patient also had clinical manifestations of autoimmunity,such as eczematous skin lesion,inflammatory bowel disease(IBD),and intractable diarrhea,suggesting compromised T cell tolerogenic functions.Immunologic analysis showed selective absence of CD8+ T cells in the periphery and the presence of CD4+ T cells that failed to respond to PHA.B cells from the patient also did not proliferate in response to PWM stimulation.CD4+ T cells subset analysis showed the frequency of Tfhs and Tregs in the patient was lower compared to the normal reference.Residual ZAP70 expression and novel compound heterozygous mutations(c.598-599 del CT,p.L200 fs X28;c.847C>T,p.R283X)in ZAP70 were identified in the patient.Conclusions: The article presents clinical and immunological features of the first case from China with novel compound heterozygous mutations in ZAP70.Infants with selected CD8 deficiency and severe autoimmune disorders or exaggerated inflammation should be screened for ZAP70 deficiency.