Laboratory Diagnosis of Human Papillomavirus Virus Infection in Female Genital Tract
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Resident’s Page Laboratory diagnosis of human papillomavirus virus infection in female genital tract Rahul Dixit, Chintan Bhavsar, Y. S. Marfatia Department of Skin VD,Government Medical College and SSG Hospital,Vadodara, Gujarat, India Address for correspondence: Dr. YS. Marfatia, Department of Skin VD, Government Medical College and SSG Hospital, Vadodara, Gujarat, India. E-mail: [email protected] INTRODUCTION spreading the virus. Asymptomatic HPV/DNA shedding from perianal region seems to be very common, 78.9% A human papillomavirus (HPV), a member of the in AIDS patients with advanced disease stage.[4] papillomavirus, is a double-stranded DNA virus and produces cytopathic effect in epithelium. Genital There was no consistent evidence that condom use mucosal infection is persistent and multifocal and reduces the risk of becoming HPV DNA – positive can be subclinical. (subclinical HPV infection). On the other hand, the risk for genital warts, CIN 2-3 and invasive cervical cancer More than 30 to 40 types of HPV are typically were reduced by condom use.[5] transmitted through sexual contact and infect the [1] anogenital region. Some sexually transmitted HPV LAB DIAGNOSIS types may cause genital warts. Persistent infection with "high-risk" HPV types different from the ones The traditional methods of viral diagnosis such that cause skin warts, may progress to precancerous as electron microscopy, cell culture, and certain lesions and invasive cancer.[2] HPV infection is a immunological methods are not suitable for HPV cause of nearly all cases of cervical cancer;[3] however, detection. HPV cannot be cultured in cell cultures. most infections with these types do not cause disease. The important methods to diagnose HPV infection are: All HPV infections involve the transmission from one • Colposcopy and acetic acid test infected individual to another through direct skin-to • Biopsy skin-contact. This may occur through skin-to-skin • DNA test (PCR, Southern Blot Hybridization, In transmission via the epidermis due to direct contact of a plantar wart virus with broken skin, sexually during intercourse, or orally during sexual activity or kissing. Symptomatic HPV infection is only the tip of the iceberg [Figure 1]. Asymptomatic shedding is much more common in women with HIV/AIDS and asymptomatic shedders carry high potential for Access this article online Quick Response Code: Website: www.ijstd.org DOI: 10.4103/0253-7184.81257 Figure 1: HPV- Subclinical, multifocal and persistent How to cite this article: Dixit R, Bhavsar C, Marfatia YS. Laboratory diagnosis of human papillomavirus virus infection in female genital tract. Indian J Sex Transm Dis 2011;32:50-2. 50 Indian Journal of Sexually Transmitted Diseases and AIDS 2011; Vol. 32, No. 1 Dixit, et al.: Lab diagnosis of genital hpv in females Situ Hybridization) as mild dyskaryosis. • Pap smear • Women must be referred for colposcopy after one test reported as moderate dyskaryosis or severe Colposcopy and acetic acid test dyskaryosis, at least 90% of women with such Colposcopy is a procedure performed by test results should be seen in a colposcopy clinic specially trained clinicians as an outpatient within four weeks of referral. Women must be procedure using a low-powered microscope, the referred for colposcopy after one test reported colposcope.[6] Colposcopy is the examination of the as possible invasion or reported as glandular cervix, vagina, and in some instances the vulva neoplasia, and 90% should be seen urgently after the application ofacetic acid solution; coupled within two weeks of referral with obtaining colposcopically directed biopsies of all lesions suspected of representing neoplasia.[7] Biopsy Colposcopic findings are graded according to degree Colposcopy allows tissue sampling (biopsy) that is of acetowhite lesion, surface contour, mosaic pattern, targeted to the abnormal areas. In fact, the biopsy and punctuation. Greater abnormalities of these of abnormal areas is a critical part of colposcopy parameters are related to severity of the lesions. because treatment will depend on how severe the abnormality is on the biopsy sample. If the biopsy Acetic acid test results show pre-cancer (dysplasia) or cancer, then • Soaking acetic acid into suspicious lesions can treatment is recommended. The dysplasia may be enhance the degree of suspicion in lesions mild, moderate, or severe. without classic features. • The method involves applying a 3−5% acetic Excisional biopsy is recommended when colposcopic acid–moistened gauze pad for 5-10 minutes on appearances indicate high grade abnormality, when suspected lesions of the penis, cervix, labia, or low grade colposcopic change is associated with perianal area. severe dyskaryosis or worse, or when a lesion • Inconspicuous, flat, genital lesions that might be extends into the canal. difficult to assess become visible. Genital warts, dysplastic, and neoplastic tissues turn white In genital warts, the most characteristic feature is the (acetowhite). presence of koilocytes, which are mature squamous • False-positive results are common and can result cells with clear perinuclear zone. The nuclei of from anything that causes parakeratosis (e.g., koilocytes may be enlarged and hyper chromatic, candidiasis, psoriasis, lichen planus, healing double nuclei are seen often as well. epithelium, sebaceous glands). • The acetic acid test should not be used for DNA techniques routine screening. Initial methods of HPV detection used were • It can be used for visualizing subclinical genital direct probe hybridization such as dot blot and HPV-associated lesions, identifying lesions for Southern blot. Besides being labor-intensive and target biopsy, and for demarcating lesions during time consuming, they had low sensitivity, required surgical therapy.[8] large amounts of DNA in clinical samples, and have largely been superseded by amplification technology, The use of colposcopy screening is only to be which has allowed detection of low-level virus copy recommended for numbers in clinical samples. The established routine • Immunosuppressed transplant recipients. method for viral detection is the hybridization of • Human immunodeficiency virus (HIV) positive viral nucleic acids. The two main techniques are: women. • Women with three consecutive inadequate Hybrid capture HPV DNA Test 2 (hc2) samples; after three tests in a series reported as HC2 in conjunction with the Pap test is now borderline nuclear change in squamous cells; and approved by the FDA.[9]Since the FDA-approved be referred for colposcopy after one test reported Hybrid Capture 2 test can detect as little as 1 pg as borderline nuclear change in endocervical of HPV DNA/ml; its sensitivity and specificity cells. are almost comparable with PCR-based detection • Positive cervical cytology for malignant cells or methods. The advantages of the Hybrid Capture 2 suspicious cells but clinically normal looking test are the relatively simple handling and good cervix. reproducibility of results, which make this test the • Women must be referred after two tests reported best standardized HPV detection method. While the Indian Journal of Sexually Transmitted Diseases and AIDS 2011; Vol. 32, No. 1 51 Dixit, et al.: Lab diagnosis of genital hpv in females exact HPV type cannot be identified, "low-risk" (6, diethylstilbestrol (DES) in utero, and have been 11, 42, 43, 44) and “high-risk" (16, 18, 31, 33, 35, treated for cervical intraepithelial neoplasia (CIN) 39, 45, 51, 52, 56, 58, 59, 68) HPV genotype groups 2, CIN 3, or cervical cancer. (HR HPV and LR HPV) are detected. HPV/HIV CO – INFECTION Polymerase chain reaction Intraepithelial neoplasia (IEN) is common in HPV PCR is a selective target amplification assay capable infected patients with HIV/AIDS. There are no of exponential and reproducible increase in the clinical markers that can diagnose early IEN, so HPV sequences present in biological specimens. The it is necessary to biopsy and genotype all HIV amplification process can theoretically produce one positive patients with condylomata accuminata billion copies from a single double stranded DNA before treatment. molecule after 30 cycles of amplification.[10] REFERENCES Indications • Primary Screening in Conjunction with the 1. Genital HPV Infection - Fact Sheet. Centers for Disease Control and Prevention (CDC).[Last updated on 2009 Nov 24].Available from: Papanicolaou (Pap) http://www.cdc.gov/std/HPV/STDFact-HPV.htm.[Last accessed on • Test or as a Stand-Alone Test for women over 30 2011 Mar 15]. years of age 2. Human Papilloma Virus.[Last updated on 2011 Mar 9].Available from:http://en.wikipedia.org/wiki/Human_papillomavirus.Last accessed on 2011 Mar 13]. Pap smear or Pap test 3. Walboomers JM, Jacobs MV, Manos MM. Human papillomavirus • It is a screening test first describe by is a necessary cause of invasive cervical cancer worldwide. J Papanicolaou and Traut. Pathol 1999;189:12-9. • Apart from premalignant and malignant changes, 4. New Colposcopy Guidelines - what are the implications for the viral infections like HPV infection and Herpes cytology services? [Last updated on 2005] Available from:http:// can also be detected. www.curran.pwp.blueyonder.co.uk/Colpo.htm. [Lastaccessed on 2011 Mar 13]. • Positive test requires further confirmatory tests 5. Sweet RL, Gibbs RS. Human papilloma virus. Infectious Diseases like coloscopy, cervical biopsy, and DNA tests of the Female Genital Tract. Chapter6. Available from:http://books. like PCR. google.co.in/books?id=wuR_ngItU5oCandpg=PA88andlpg=PA8