Inflammatory biomarkers and soft tissue changes among patients commencing second-line antiretroviral therapy after first-line virological failure.INTRODUCTION
 We explored associations of inflammatory and immune activation biomarkers at baseline and percentage gain in peripheral and trunk fat and lean mass over 96 weeks in patients with confirmed virological failure initiating lopinavir-anchored second-line antiretroviral therapy (ART) regimens.


 We measured baseline plasma concentration of interleukin (IL)-6, tumour necrosis factor (TNF), neopterin, IL-6, high-sensitivity C-reactive protein (hs-CRP), D-dimer, soluble cluster of differentiation 14 (sCD14), and soluble CD163 in 123 participants of the SECOND-LINE body composition substudy.  Linear regression assessed the association between biomarkers and percentage gain in limb/trunk fat and lean mass, adjusting for age, nucleoside or nucleotide reverse transcriptase inhibitor (N(t)RTI) use, body mass index, ethnicity, smoking, viral load, CD4+ T-cell counts, smoking, duration of ART use, and cholesterol.


 Mean (standard deviation) age was 38 (7.3) years, CD4+ T-cell count was 252 (185.9) cells/μl, human immunodeficiency virus viral load was 4.2 (0.9) log10 copies/ml, 47% (58/123) were in the N(t)RTI arm (vs. raltegravir [RAL] arm in 53%); 56.1% (69/123) were females.  In adjusted analyses, for every log10 increase in baseline levels of IL-6, neopterin, and D-dimer, the percentage gain in peripheral fat over 96 weeks was 11.8% (95% confidence interval [CI]: 0.9-22.6, P = 0.033); neopterin, 11.2% (95% CI: 3.2-19.2, P = 0.007); D-dimer 9.6% (95% CI: 3.1-15.9, P = 0.004), respectively.  The associations remained significant when analysis was stratified by N(t)RTI vs. RAL and included only patients with viral suppression at week 48.  A significant gradient in lean mass gain was seen across quartiles of IL-6, TNF, neopterin, hsCRP, D-dimer, and sCD14.


 CONCLUSION
 Inflammatory biomarkers provide important mechanistic insights into the pathogenesis of limb fat and lean mass changes independently of ART.
C