Human papillomavirus-specific antibody status in oral fluids modestly reflects serum status in human immunodeficiency virus-positive individuals

Abstract

Serological assays are valuable tools for studies of the epidemiology of human papillomaviruses (HPVs). The efficacy of a less invasive oral-fluid assay for detection of HPV antibodies was examined. Matched serum, saliva, and oral mucosal transudate (OMT) specimens collected from 150 human immunodeficiency virus-seropositive patients were tested for immunoglobulin G antibodies against HPV-6 and HPV-11 combined (HPV-6/11) and HPV-16 capsids. Antibodies to HPV were detected in both types of oral specimens. Seroprevalence rates were 55% for HPV-6/11 and 37% for HPV-16, whereas oral prevalence rates were significantly lower (for HPV-6/11 in saliva, 31%, and in OMT, 19%; for HPV-16 in saliva, 19%, and in OMT, 17%). HPV antibody detection in OMT more accurately reflected the presence of antibodies in serum than did HPV antibody detection in saliva. More stringent saliva assay cutpoints yielded stronger associations between oropositivity and seropositivity; less stringent OMT cutpoints yielded stronger associations between oropositivity and seropositivity. Although HPV antibodies were detected in oral fluids, further optimization of the assay is necessary before oral-fluid testing can be implemented as a reliable alternative to serum testing for HPV.

Figures

FIG. 1.

Correlations between oral-specimen adj OD values and serum adj OD values for the first cohort. Adj OD values were treated as continuous variables, and paired samples were compared by using the Pearson correlation coefficient (r statistic). (A) HPV-6/11, saliva versus serum; (B) HPV-6/11, OMT versus serum; (C) HPV-16, saliva versus serum; (D) HPV-16, OMT versus serum.

FIG. 2.

Correlations between oral-specimen adj OD values and serum adj OD values for the second cohort. (A) HPV-6/11, saliva versus serum; (B) HPV-6/11, OMT versus serum; (C) HPV-16, saliva versus serum; (D) HPV-16, OMT versus serum.

FIG. 3.

Prevalence of HPV-6/11- and HPV-16-specific IgG in serum and oral specimens. (A) Prevalence of HPV antibodies in samples from the first cohort (unstimulated OMT, n = 100); (B) prevalence of HPV antibodies in samples from the second cohort (stimulated OMT, n = 50). Seropositivity was defined by a negative control population. Oropositivity was defined by the arbitrarily selected cutpoint of 0.100.

FIG. 4.

Prevalence of HPV IgG in specimens when negative control cutpoints were used. Both seropositivity and oropositivity were determined by using cutpoints derived from samples collected from children under the age of 10 years. Only the samples in the second cohort (n = 50) are represented.

FIG. 5.

Correlations between serum HPV IgG titers and oral-specimen adj OD values. Seropositive samples from both cohorts were diluted twofold and tested for HPV antibody titers, and the Pearson r statistic was used to examine correlations between serum antibody titers and oral-specimen OD values. (A) HPV-6/11, saliva adj OD versus serum antibody titer, shown as the area under the curve (AUC); (B) HPV-6/11, OMT adj OD versus serum antibody titer; (C) HPV-16, saliva adj OD versus serum antibody titer; (D) HPV-16, OMT adj OD versus serum antibody titer.