Role of persistant HPV infection in development of precancerous lesions is essential and multiple HPV infection correlation with E6/E7 RNA expression is shown in some studies (Anderson 2012). There are no studies in Latvia on HR HPV profile and E6/E7 RNA expression in patients with cervical intraepithelial neoplasia.
49 women aged 18-65 with abnormal cytology referred for colposcopy during their first visit to Reference Colposcopy Centre in Riga East Clinical University Hospital in July 2016-February 2017 were included in the study. Results of vaginal pH , native microscopy of frontal vaginal fornix, material from cervix for presence of high risk (HR) HPV DNA types 16/18, 31, 33, 45, 58, HR- HPV E6/E7 common RNA and histology after punch biopsy taken under colposcopy control were analyzed for each patient. Vaginal pH was measured using Machery Nagel pH strips. Microscopic examination of wet mounts was interpreted according to Donder’s modification of Schröder’s classification. HPV types and HPV RNA were identified by real time PCR test.
14 patients with low grade squamous intraepithelial lesions (LSIL), 32 with high grade SIL (HSIL), 2 patient with atypical squamous cells of undetermined significance (ASCUS) and 1 patient with atypical glandular cells of undetermined significance (AGUS) were included in the study. HR- HPV DNA was detected in 26 cases (HPV positive group), 23/26 was multiple HPV infection. The most common HPV type was HPV 58, which was isolated from 23 women, HPV16/18 was found in 16 patients, HPV 31 in 13 cases and 33 in 11 patients, HPV 45 in 11 patients. Elevated pH >4.4 was detected in 12/26 patients from HPV positive group and in 5/23 cases from HPV negative group (p=0,02). Lactobacillary grade III prevalence in both groups did not differentiate significantly in our study, 7 cases in HPV positive group and 8 cases in HPV negative group. HPV E6/E7 RNA expression was found in 26/26 cases of HR-HPV DNA positive group and in 13 cases of HPV negative group (p<0,01) . Multiple HPV types were found in 19/34 patients with CIN 2+ histology. CIN2+ in histology reports was more likely correlate with HPV E6/E7 RNA expression in both groups: 21 /26 patients in HPV positive group and 13 /13 cases from HPV DNA negative group (p=0,05).
Our findings suggest a possible association between multiple HPV DNA, E6/E7 RNA expression and high grade cervical precancerous lesions, but we analyzed only 6 HR-HPV types and E6/E7 RNA prevalence in HPV negative group may be associated with other HR –HPV types. More detailed study will be required in future.