Performance and pre-analytical stability of self-collected samples versus clinician cervical samples for the detection of HPV16, HPV18 and a pool of 12 other HPV types on the Roche Cobas 8800 System.

This study aimed to validate the agreement between human papillomavirus (HPV) tests self-collected samples versus clinician cervical specimens, and the pre-analytical stability of self-sampling. One hundred and fifty-seven women aged between 25 and 65 years who presented to the gynaecological department of the "CLEMENTVILLE" clinic in Montpellier voluntarily participated in HPV screening by self-sampling. Polymerase chain reaction was used to detect the presence of HPV16, HPV18 and a pool of 12 other HPV types on the Roche Cobas 8800 System. Median age was 40 years (range 20-73 and IQR 31-49 years). The overall HPV prevalence on the population studied was 27%. The agreement between clinician cervical samples and self-collected vaginal presented good agreement (Kappa =0.90) and high sensitivity (0.91) and specificity (0.98). For swabs stored for 7 days at room temperature, the HPV results presented substantial agreement (Kappa =0.89) and high sensitivity (0.97) and specificity (0.93). Our data showed that the HPV assay performed in the self-collected vaginal samples have high consistency of results with the clinician cervical samples. The use of self-collected cervical sample could be a simple and inexpensive approach in cervical cancer screening programs due to their high pre-analytical stability.

Detection of memory B lymphocytes specific to hepatitis B virus (HBV) surface antigen (HBsAg) from HBsAg-vaccinated or HBV-immunized subjects by ELISPOT assay.

To improve the investigation of the role of human memory B lymphocytes following hepatitis B virus (HBV) infection or vaccination, we developed a method to characterize circulating memory B cells specific to hepatitis B surface antigen (HBsAg). Our approach combined: (1) purification of CD19+ cells, (2) CD40-CD40L polyclonal stimulation, and (3) enumeration of memory B cells differentiated into anti-HBs antibody (Ab)-secreting cells (HBs-SCs) by a HBs-ELISPOT assay. In this way, HBs-SCs were detected in 17 HBsAg-vaccinated and nine HBV-immunized subjects including four individuals with serum anti-HBs Ab levels < 10 mIU/ml, but not in six controls. IgG+, IgA+ plus IgM+ HBs-SCs, representing 5-1736 cells/10(6) circulating B cells and 0.02-0.58% of total immunoglobulin-SCs generated by the B cell polyclonal stimulation, were counted by an Ig two-colour ELISPOT assay. In addition, anti-HBs Abs were found in 8/15 supernatants recovered from B cell cultures which contained HBs-SCs, suggesting that the HBs-ELISPOT assay is more reliable in tracking HBsAg-specific memory B cells than ELISA measurement of anti-HBs Abs secreted in supernatants. This new approach could be useful to explore the presence and the longevity of HBsAg-specific memory B cells in vaccinated and immunized subjects, in chronic HBV infection and after liver transplantation for HBV-related disease.