Effect of Nadir CD4+ T Cell Count on Clinical Measures of Periodontal Disease in HIV+ Adults before and during Immune Reconstitution on HAART

<div><p>Background</p><p>The contribution of HIV-infection to periodontal disease (PD) is poorly understood.  We proposed that immunological markers would be associated with improved clinical measures of PD.</p> <p>Methods</p><p>We performed a longitudinal cohort study of HIV-infected adults who had started highly active antiretroviral therapy (HAART) <2 years. PD was characterized clinically as the percent of teeth with ≥1 site with periodontal probing depth (PPD) ≥5.0mm, recession (REC) >0mm, clinical attachment level (CAL) ≥4.0mm, and bleeding on probing (BOP) at ≥4 sites/tooth and microbiologically as specific periodontopathogen concentration. Linear mixed-effects models were used to assess the associations between immune function and PD.</p> <p>Results</p><p>Forty (40) subjects with median 2.7 months on HAART and median nadir CD4+ T-cell count of 212 cells/μl completed a median 3 visits. Over 24 months, CD4+ T-cell count increased by a mean 173 cells/µl (p<0.001) and HIV RNA decreased by 0.5 log₁₀ copies/ml (p<0.001); concurrently, PPD, CAL and BOP decreased by a mean 11.7%, 12.1%, and 14.7% respectively (all p<0.001). Lower nadir CD4+ T-cell count was associated with worse baseline REC (-6.72%; p=0.04) and CAL (9.06%; p<0.001). Further, lower nadir CD4+ T-cell count was associated with a greater relative longitudinal improvement in PPD in subjects with higher baseline levels of <i>Porphyromonas gingivalis</i> (p=0.027), and BOP in subjects with higher baseline levels of <i>Porphyromonas gingivalis</i> or <i>Treponema denticola</i> (p=0.001 and p=0.006 respectively). Longitudinal changes from baseline in CD4+ T-cell count and level of HIV RNA were not independently associated with longitudinal changes in any clinical markers of PD.</p> <p>Conclusion</p><p>Degree of immunosuppression was associated with baseline gingival recession. After HAART initiation, measures of active PD improved most in those with lower nadir CD4+ T-cell counts and higher baseline levels of specific periodontopathogens. Nadir CD4+ T-cell count differentially influences periodontal disease both before and after HAART in HIV-infected adults.</p> </div

Associations of <i>Toll-Like Receptor</i> and <i>β-Defensin</i> Polymorphisms with Measures of Periodontal Disease (PD) in HIV+ North American Adults: An Exploratory Study

<div><p>Polymorphisms in toll-like receptor (<i>TLR</i>) and β-defensin (<i>DEFB</i>) genes have been recognized as potential genetic factors that can influence susceptibility to and severity of periodontal diseases (PD). However, data regarding associations between these polymorphisms and PD are still scarce in North American populations, and are not available in HIV+ North American populations. In this exploratory study, we analyzed samples from HIV+ adults (n = 115), who received primary HIV care at 3 local outpatient HIV clinics and were monitored for PD status. We genotyped a total of 41 single nucleotide polymorphisms (SNPs) in 8 <i>TLR</i> genes and copy number variation (CNV) in <i>DEFB4</i>/<i>103A</i>. We performed regression analyses for levels of 3 periodontopathogens in subgingival dental plaques (<i>Porphyromonas gingivalis</i> [<i>Pg</i>], <i>Treponema denticola</i> [<i>Td</i>], and <i>Tannerella forsythia</i> [<i>Tf</i>]) and 3 clinical measures of PD (periodontal probing depth [PPD], gingival recession [REC], and bleeding on probing [BOP]). In all subjects combined, 2 SNPs in <i>TLR1</i> were significantly associated with <i>Td</i>, and one SNP in <i>TLR2</i> was significantly associated with BOP. One of the 2 SNPs in <i>TLR1</i> was significantly associated with <i>Td</i> in Caucasians. In addition, another SNP in <i>TLR1</i> and a SNP in <i>TLR6</i> were also significantly associated with <i>Td</i> and <i>Pg</i>, respectively, in Caucasians. All 3 periodontopathogen levels were significantly associated with PPD and BOP, but none was associated with REC. Instrumental variable analysis showed that 8 SNPs in 6 <i>TLR</i> genes were significantly associated with the 3 periodontopathogen levels. However, associations between the 3 periodontopathogen levels and PPD or BOP were not driven by associations with these identified SNPs. No association was found between <i>DEFB4</i>/<i>103A</i> CNV and any periodontopathogen level or clinical measure in all samples, Caucasians, or African Americans. Our exploratory study suggests a role of <i>TLR</i> polymorphisms, particularly <i>TLR1</i> and <i>TLR6</i> polymorphisms, in PD in HIV+ North Americans.</p></div

Association Between Periodontopathogen Levels and <i>TLR</i> SNPs^*.

<p>Association Between Periodontopathogen Levels and <i>TLR</i> SNPs^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164075#t002fn001" target="_blank">*</a>}.</p

Diagrammatic Representation of Instrumental Variable Analysis.

<p>Instrumental variable models use associations C and A to estimate the relationship between an exposure/risk factor and an outcome (B). Note that the instrument is not supposed to have a direct effect on the outcome, hence this line (C) is dashed. Abbreviations: <i>Pg</i>, <i>Porphyromonas gingivalis</i>; <i>Td</i>, <i>Treponema denticola</i>; <i>Tf</i>, <i>Tannerella forsythia</i>; PPD, periodontal probing depth; BOP, bleeding on probing.</p

Association Between Clinical Measures of PD and <i>TLR</i> SNPs^*.

<p>Association Between Clinical Measures of PD and <i>TLR</i> SNPs^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164075#t003fn001" target="_blank">*</a>}.</p

Characteristics of the Study Cohort^*.

<p>Characteristics of the Study Cohort^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164075#t001fn001" target="_blank">*</a>}.</p