Direct genetic correction as a new method for diagnosis and molecular characterization of MHC class II deficiency.
Major histocompatibility complex class II (MHCII) deficiency is a primary immunodeficiency resulting from defects in one of four different MHCII-specific transcription factors-CIITA, RFX5, RFXAP, and RFXANK. Despite this genetic heterogeneity, the phenotypical manifestations are homogeneous. It is frequently difficult to establish a definitive diagnosis of the disease on the basis of clinical and immunological criteria. Moreover, the phenotypical homogeneity precludes unambiguous identification of the regulatory gene that is affected. Identification of the four genes mutated in the disease has now allowed us to develop a rapid and straightforward diagnostic test for new MHCII-deficiency patients. This test is based on direct correction of the genetic defect by transduction of cells from patients with lentiviral vectors encoding CIITA, RFXANK, RFX5, or RFXAP. We have validated this approach by defining the molecular defects in two new patients. The RFXANK vector restored MHCII expression in a T cell line from one patient. The RFXAP vector corrected primary cells (PBL) from a second patient. Molecular analysis confirmed the presence of homozygous mutations in the RFXANK and RFXAP genes, respectively. Direct genetic correction represents a valuable tool for the diagnosis and classification of new MHCII-deficiency patients.
Matheux
Franck
F
Department of Genetics and Microbiology, University of Geneva Medical School, Geneva, Switzerland.
Ikinciogullari
Aydan
A
Zapata
David A
DA
Barras
Emmanuèle
E
Zufferey
Madeleine
M
Dogu
Figen
F
Regueiro
José R
JR
Reith
Walter
W
Villard
Jean
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005816:Genetic Complementation Test; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000145:classification / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D016086:Lentivirus / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D000071701:Regulatory Factor X Transcription Factors; D015203:Reproducibility of Results; D013601:T-Lymphocytes / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014161:Transduction, Genetic
D004268:DNA-Binding Proteins; D000949:Histocompatibility Antigens Class II; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; C093524:RFX5 protein, human; C117892:RFXANK protein, human; C413004:RFXAP protein, human; D000071701:Regulatory Factor X Transcription Factors; D015534:Trans-Activators; D014157:Transcription Factors