Evaluation of the anti-East Asian CagA-specific antibody for CagA phenotyping.
The determination of the cagA genotype is generally based on sequencing the variable 3' region of the cagA gene. In a previous study, we successfully generated an anti-East Asian CagA-specific antibody (anti-EAS Ab) immunoreactive only with the East Asian CagA and not with the Western CagA. In a small number of Japanese patients, anti-EAS Ab appeared to be a useful tool for phenotyping CagA immunohistochemically. The present study was conducted to validate the anti-EAS Ab immunohistochemistry method in a larger number of patients from Vietnam and Thailand. A total of 385 Vietnamese and Thais were recruited. Helicobacter pylori status was determined by a combination of three methods, including culture, histology, and immunohistochemistry with anti-H. pylori antibody. The sensitivity, specificity, and accuracy of the anti-EAS Ab immunohistochemistry method for the diagnosis of CagA phenotype were calculated based on the results of the cagA sequencing as the gold standard. The sensitivity, specificity, and accuracy of our immunohistochemistry method were 96.7%, 97.9%, and 97.1%, respectively. Moreover, anti-EAS Ab was not cross-reactive with noninfected gastric mucosa. In conclusion, immunohistochemistry with anti-EAS Ab appears to be a good method for determination of CagA phenotype.
Department of Molecular Pathology, Faculty of Medicine, Oita University, Yufu-city, Oita, Japan.
Lam Tung
LT
Nguyen
Tomohisa
T
Uchida
Akiko
A
Kuroda
Yoshiyuki
Y
Tsukamoto
Tuan Dung
TD
Trinh
Long
L
Ta
Hong Bang
HB
Mai
Dang Quy Dung
DQ
Ho
Hoa Hai
HH
Hoang
Ratha-Korn
RK
Vilaichone
Varocha
V
Mahachai
Takeshi
T
Matsuhisa
Yoko
Y
Kudo
Tadayoshi
T
Okimoto
Masaaki
M
Kodama
Kazunari
K
Murakami
Toshio
T
Fujioka
Yoshio
Y
Yamaoka
Masatsugu
M
Moriyama
D000328:Adult; D000818:Animals; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial / Q000032:analysis* / Q000276:immunology; D001426:Bacterial Proteins / Q000032:analysis* / Q000276:immunology; D003429:Cross Reactions; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology; D016480:Helicobacter pylori / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D013785:Thailand; D014744:Vietnam; D037521:Virulence Factors / Q000032:analysis* / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori