A controlled study of adenoviral-vector-mediated gene transfer in the nasal epithelium of patients with cystic fibrosis.
BACKGROUND
Cystic fibrosis is a monogenic disease that deranges multiple systems of ion transport in the airways, culminating in chronic infection and destruction of the lung. The introduction of a normal copy of the cystic fibrosis transmembrane conductance regulator (CFTR) gene into the airway epithelium through gene transfer is an attractive approach to correcting the underlying defects in patients with cystic fibrosis. We tested the feasibility of gene therapy using adenoviral vectors in the nasal epithelium of such patients.


METHODS
An adenoviral vector containing the normal CFTR complementary DNA in four logarithmically increasing doses (estimated multiplicity of infection, 1, 10, 100, and 1000), or vehicle alone, was administered in a randomized, blinded fashion to the nasal epithelium of 12 patients with cystic fibrosis. Gene transfer was quantitated by molecular techniques that detected the expression of CFTR messenger RNA and by functional measurements of transepithelial potential differences (PDs) to assess abnormalities of ion transport specific to cystic fibrosis. The safety of this treatment was monitored by nasal lavage and biopsy to assess inflammation and vector replication.


RESULTS
The adenoviral vector was detected in nasal-lavage fluid by culture, the polymerase chain reaction (PCR), or both in a dose-dependent fashion for up to eight days after vector administration. There was molecular evidence of gene transfer by reverse-transcriptase PCR assays or in situ hybridization in five of six patients treated at the two highest doses. However, the percentage of epithelial cells transfected by the vector was very low (< 1 percent), and measurement of PD across the epithelium revealed no significant restoration of chloride transport or normalization of sodium transport. At the lower doses of vector, there were no toxic effects. However, at the highest dose there was mucosal inflammation in two of three patients.


CONCLUSIONS
In patients with cystic fibrosis, adenoviral-vector-mediated transfer of the CFTR gene did not correct functional defects in nasal epithelium, and local inflammatory responses limited the dose of adenovirus that could be administered to overcome the inefficiency of gene transfer.
Knowles
M R
MR
Department of Medicine, School of Public Health, University of North Carolina at Chapel Hill 27599-7020, USA.
Hohneker
K W
KW
Zhou
Z
Z
Olsen
J C
JC
Noah
T L
TL
Hu
P C
PC
Leigh
M W
MW
Engelhardt
J F
JF
Edwards
L J
LJ
Jones
K R
KR
D000260:Adenoviruses, Human / Q000235:genetics; D000328:Adult; D002712:Chlorides / Q000378:metabolism; D003550:Cystic Fibrosis / Q000378:metabolism / Q000628:therapy*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003673:Defective Viruses; D004311:Double-Blind Method; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D005260:Female; D018014:Gene Transfer Techniques / Q000009:adverse effects; D015316:Genetic Therapy / Q000009:adverse effects / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D017136:Ion Transport; D008297:Male; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000235:genetics*; D009297:Nasal Mucosa / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis
C505032:CFTR protein, human; D002712:Chlorides; D008565:Membrane Proteins; D012333:RNA, Messenger; D019005:Cystic Fibrosis Transmembrane Conductance Regulator