Loop-mediated isothermal amplification method for detection of human papillomavirus type 6, 11, 16, and 18

A new method was developed for detection of human papillomavirus (HPV) by loop-mediated isothermal amplification (LAMP), which was compared with the polymerase chain reaction (PCR), and real-time PCR for specificity and sensitivity. All initial validation studies with the control DNA proved to be type-specific. In order to evaluate the reliability of HPV type-specific LAMP detecting HPV DNA from clinical samples, tissue specimens were obtained from 27 patients with external genital polypoid lesions. The histologic diagnoses included condyloma acuminatum (n=21), bowenoid papulosis (n=2), seborrheic keratosis (n=2), epidermolytic acanthoma (n=1), and hairy nymphae (n=1). HPV-6 DNA and HPV-11 DNA were detected in 18 and 3 of 21 condylomata acuminata, respectively, and there was no simultaneous infection. HPV-16 DNA was detected in one of two bowenoid papuloses. HPV DNA was not detected in the seborrheic keratoses, epidermolytic acanthoma, and hairy nymphae. These results correlated perfectly with those from real-time PCR analysis. Most positive samples contained high copy numbers of HPV DNA. HPV-11 DNA was detected in one case that could not be detected by PCR. The average reaction time was about 59 min. There was a linear correlation between the genome quantity and reaction time to reach the threshold. The LAMP method has an additional advantage as a quantitative method, and is superior in terms of sensitivity, specificity, rapidity, and simplicity, and can potentially be a valuable tool for the detection of HPV DNA.