Quantitative analysis of IL-10 and IFN-gamma mRNA levels in normal cervix and human papillomavirus type 16 associated cervical precancer

Human papillomavirus type 16 is a major factor in cervical carcinogenesis. Inappropriate cytokine synthesis may direct the local immune response away from a type-1 (cellular) pattern and may subsequently contribute to the dev elopment and progression of precancer. Quantitative reverse transcription-p olymerase chain reaction (RT-PCR) using a competitive mimic was carried out to determine type-1 (interferon gamma (IFN-gamma)) and type-2 (interieukin -10 (IL-10)) cytokine mRNA levels in whole cervical specimens (without micr odissection) from seven normal and nine HPV-16 positive CIN formalin-fixed paraffin-embedded tissues. Microdissection was used to measure separately t he epithelial and sub-epithelial levels of IFN-gamma and IL-10 MRNAs in 11 specimens of normal cervix and 25 HPV-16 positive CIN (nine CIN 1, seven CI N 2 and nine CIN 3). IFN-gamma mRNA was lower in CIN than normal (p = 0.04) . IL-10 mRNA level in CIN was significantly higher (p = 0.005) than in norm al cervix (before microdissection). Epithelial IFN-gamma mRNA showed a sign ificant decrease in all grades of CIN (median = 3.58) compared with normal (7.74) (p < 0.05), but there was no significant difference between the grad es. A significant decrease in sub-epithelial IFN-gamma mRNA was found in CI N 1(9.81), CIN 2 (3.82) and CIN 3 (4.62) compared with normal cervix (27.35 ) (p < 0.05). Also, sub-epithelial IFN-gamma mRNA was significantly lower i n CIN 2 and CIN 3 than in CIN I (p = 0.005 and 0.0005, respectively). IL-10 was detected in the epithelium of only one of 11 normal and one of 25 CIN, but sub-epithelial IL-10 was significantly higher in CIN 2 (0.08) and CIN 3 (0.26) than in normal (0.00) (p = 0.036 and 0.0032, respectively). There was no significant difference in the sub-epithelial level of IL-10 between normal and CIN 1 (0.00) (p = 0.96). Our results suggest that reduced epithe lial and sub-epithelial IFN-gamma, as well as increased sub-epithelial IL-1 0 synthesis may play a role in the development and progression of HPV-16 as sociated cervical precancer. Copyright (C) 2001 John Wiley & Sons, 1 Ltd.