Hair as a Biomarker

Monica Gandhi MD, MPH; Professor of Medicine, Division of HIV, Infectious Diseases, and Global Medicine, UCSF

As it grows, human hair incorporates compounds--including antiretroviral medications (ARVs)--that have circulated in the body. Concentrations of these compounds reflect the quantity of drugs taken over the course of weeks to months. Research conducted by the UCSF Hair Analytical Lab (HAL) shows that ARV levels in hair are more reliable predictors of treatment outcomes than self-reported adherence14 or single-assay measurements of plasma ARV concentrations.5,6

UCSF HAL pioneered the use of small hair samples to monitor exposure and adherence to ARVs for people living with HIV/AIDS.1-5,7-27 Lab members developed methods to extract and analyze commonly prescribed ARVs from hair,8,9 and demonstrated that hair concentrations of ARVs are the strongest independent predictor of virologic success in HIV-infected patients.1-5,10

Reliability and ease of use

Successful virologic suppression of HIV depends on how reliably patients are taking their medications over the course of time.28 The use of hair measurements can circumvent many limitations of common tools for monitoring adherence to medication regimens. Hair analysis can help clinicians make reliable estimates of long-term medication exposure.29,30

Moreover, hair sample collection is noninvasive and does not require specific skills, sterile equipment, or specialized storage. Samples can be stored at room temperature for long periods prior to analysis and shipped without taking the precautions associated with biohazardous materials.

In comparison, other techniques have a variety of barriers. Single-assay measurements of plasma ARV concentrations reflect whether a patient took a prescribed drug in the days prior to the test, but cannot detect whether doses were frequently missed over the weeks or months leading up to the clinic visit.31,32 As a result, plasma levels are susceptible to "white coat effects," whereby adherence improves transiently prior to clinic visits.33,34 Drug levels in peripheral blood mononuclear cells (PBMCs) relay information on exposure over longer periods (7-14 days), but processing, isolating, and counting PBMCs are costly and technically challenging. Dried blood spots (DBS) are easier to collect and process than PBMCs,35 and drug levels in red blood cells (RBCs) from DBS samples represent longer-term exposure,36 but DBS assays require phlebotomy, a cold chain, standardization against hemoglobin concentrations, and adequate sample volume for interpretation.37

A powerful research tool

The longitudinal exposure data provided by hair samples are effective for studying dosing, benefits, and adverse effects of drugs.

UCSF HAL is able to analyze multiple ARVs in hair, including nevirapine, efavirenz, atazanavir, lopinavir, ritonavir, raltegravir, darunavir, dolutegravir, tenofovir, and emtricitabine. This lab is also able to assess adherence with isoniazid19-21 during latent and active TB infection treatment. Most HAL assays have been peer reviewed and approved by the NIH DAIDS-supported Clinical Pharmacology and Quality Assurance (CPQA) program.38

Notable findings

UCSF HAL research has shown:

  • A strong correlation between tenofovir (TFV) dosage and concentrations of TFV in hair in HIV-negative individuals22
  • A strong correlation between hair levels of TFV and DBS concentrations of TFV-diphosphate, paving the way for the use of hair measures in the setting of preexposure prophylaxis (PrEP)23,24
  • Hair levels of tenofovir are associated with PrEP-related toxicities in an open-label study, specifically declines in renal function27
  • The relationship between hair concentrations of ARVs and other pharmacologic and traditional adherence measures in the context of PrEP 23,24

In the prevention of mother-to-child transmission:

  • Hair levels of ARVs in an infant can reflect exposure to maternal ARVs administered during pregnancy and breastfeeding11,14
  • Hair levels of ARVs are strong predictors of virologic suppression during the critical periods of pregnancy and breastfeeding3

UCSF HAL research also has shown increases in hair ARV levels in various populations before and after adherence interventions.17,18

Feasibility and cost

UCSF HAL research reveals high rates of acceptability and feasibility (>95%) of collecting hair samples for hair ARV monitoring in African and Asian settings.5,12,23 Gathering samples with scissors instead of phlebotomy needles may be particularly desirable in assessing drug treatment adherence among children.11,13,39

A high-throughput hair analysis laboratory such as UCSF HAL can assay hair samples economically. The HAL staff recently developed a low-cost assay for measuring nevirapine concentrations in hair that can be performed by local laboratories in resource-limited settings,16 and the team is working to develop lower-cost measures for other drugs.

References:

  1. Gandhi M, Ameli N, Bacchetti P, Gange SJ, Anastos K, Levine A, Hyman CL, Cohen M, Young M, Huang Y, Greenblatt RM. Protease inhibitor levels in hair strongly predict virologic response to treatment. AIDS. 2009 Feb 20;23(4):471-8. PMID: 19165084; PMCID: PMC2654235.
  2. Gandhi M, Ameli N, Bacchetti P, Anastos K, Gange SJ, Minkoff H, Young M, Milam J, Cohen MH, Sharp GB, Huang Y, Greenblatt RM. Atazanavir concentration in hair is the strongest predictor of outcomes on antiretroviral therapy. Clin Infect Dis. 2011 May;52(10):1267-75. PMID: 21507924; PMCID: PMC3079399.
  3. Koss C, Natureeba P, Mwesigwa J, Cohan D, Nzarubara B, Bacchetti P, Horng H, Clark TD, Plenty A, Ruel TD, Achan J, Charlebois ED, Kamya MR, Havlir DV, Gandhi M. Hair concentrations of antiretrovirals predict viral suppression in HIV-infected pregnant and breastfeeding Ugandan women. AIDS. 2015 Nov;29(7):825-30. PMID: 25985404; PMCID: PMC4438773.
  4. Baxi SM, Greenblatt RM, Bacchetti P, Jin C, French AL, Keller MJ, Augenbraun MH, Gange SJ, Liu C, Mack WJ, Gandhi M; Women’s Interagency HIV Study (WIHS). Nevirapine concentration in hair samples is a strong predictor of virologic suppression in a prospective cohort of HIV-infected patients. PLoS One. 2015 Jun 8;10(6):e0129100. PMID: 26053176; PMCID: PMC4460031.
  5. Prasitsuebsai W, Kerr SJ, Truong KH, Ananworanich J, Do VC, Nguyen LV, Kurniati N, Kosalaraksa P, Sudjaritruk T, Chokephaibulkit K, Thammajaruk N, Singtoroj T, Teeraananchai S, Horng H, Bacchetti P, Gandhi M, Sohn AH. Using lopinavir concentrations in hair samples to assess treatment outcomes on second-line regimens among Asian children. AIDS Res Hum Retroviruses. 2015 Oct;31(10):1009-14. PMID: 26200586; PMCID: PMC4576945.
  6. Gandhi M, Ameli N, Gange SJ, Anastos K, Bacchetti P, Cohen M, Young M, Minkoff HL, Huang Y, Greenblatt RM. Concentrations of efavirenz in hair correlate strongly with 24-hour intensive PK measurements and with virologic outcomes. In: Program and abstracts of the 17th Conference on Retroviruses and Opportunistic Infections; February 16-19, 2010; San Francisco. Poster N-154.
  7. Gandhi M, Greenblatt RM. Hair it is: the long and short of monitoring antiretroviral treatment. Ann Intern Med. 2002 Oct 15;137(8):696-7. PMID: 12379072.
  8. Huang Y, Gandhi M, Greenblatt RM, Gee W, Lin ET, Messenkoff N. Sensitive analysis of anti-HIV drugs, efavirenz, lopinavir and ritonavir, in human hair by liquid chromatography coupled with tandem mass spectrometry. Rapid Commun Mass Spectrom. 2008 Nov;22(21):3401-9. PMID: 18837069; PMCID: PMC2669487.
  9. Huang Y, Yang Q, Yoon K, Lei Y, Shi R, Gee W, Lin ET, Greenblatt RM, Gandhi M. Microanalysis of the antiretroviral nevirapine in human hair from HIV-infected patients by liquid chromatography-tandem mass spectrometry. Anal Bioanal Chem. 2011 Oct;401(6):1923-33. PMID: 21847531; PMCID: PMC3477620.
  10. van Zyl GU, van Mens TE, McIlleron H, Zeier M, Nachega JB, Decloedt E, Malavazzi C, Smith P, Huang Y, van der Merwe L, Gandhi M, Maartens G. Low lopinavir plasma or hair concentrations explain second line protease inhibitor failures in a resource-limited setting. J Acquir Immune Defic Syndr. 2011 Apr;56(4):333-9. PMID: 21239995; PMCID: PMC3073814.
  11. Gandhi M, Mwesigwa J, Aweeka F, Plenty A, Charlebois E, Ruel TD, Huang Y, Clark T, Ades V, Natureeba P, Luwedde FA, Achan J, Kamya MR, Havlir DV, Cohan D; Prevention of Malaria and HIV Disease in Tororo (PROMOTE) Study. Hair and plasma data show that lopinavir, ritonavir, and efavirenz all transfer from mother to infant in utero, but only efavirenz transfers via breastfeeding. J Acquir Immune Defic Syndr. 2013 Aug 15;63(5):578-84. PMID: 24135775; PMCID: PMC3800282.
  12. Hickey MD, Salmen CR, Tessler RA, Omollo D, Bacchetti P, Magerenge R, Mattah B, Salmen MR, Zoughbie D, Fiorella KJ, Geng E, Njoroge B, Jin C, Huang Y, Bukusi EA, Cohen CR, Gandhi M. Antiretroviral concentrations in small hair samples as a feasible marker of adherence in rural Kenya. J Acquir Immune Defic Syndr. 2014 Jul 1;66(3):311-5. PMID: 24694932; PMCID: PMC4146734.
  13. Olds PK, Kiwanuka JP, Nansera D, Huang Y, Bacchetti P, Jin C, Gandhi M, Haberer JE. Assessment of HIV antiretroviral therapy adherence by measuring drug concentrations in hair among children in rural Uganda. AIDS Care. 2015;27(3):327-32. PMID: 25483955; PMCID: PMC4305465.
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  17. Gwadz M, Cleland CM, Applegate E, Belkin M, Gandhi M, Salomon N, Banfield A, Leonard N, Riedel M, Wolfe H, Pickens I, Bolger K, Bowens D, Perlman D, Mildvan D; Heart to Heart Collaborative Research Team. Behavioral intervention improves treatment outcomes among HIV-infected individuals who have delayed, declined, or discontinued antiretroviral therapy: a randomized controlled trial of a novel intervention. AIDS Behav. 2015 Oct;19(10):1801-17. PMID: 25835462; PMCID: PMC4567451.
  18. Hickey MD, Salmen CR, Omollo D, Mattah B, Fiorella KJ, Geng EH, Bacchetti P, Blat C, Ouma GB, Zoughbie D, Tessler RA, Salmen MR, Campbell H, Gandhi M, Shade S, Njoroge B, Bukusi EA, Cohen CR. Pulling the network together: quasi-experimental trial of a patient-defined support network intervention for promoting engagement in HIV care and medication adherence on Mfangano Island, Kenya. J Acquir Immune Defic Syndr. 2015 Aug 1;66(3):311-5. PMID: 25984711; PMCID: PMC4485532.
  19. Gerona R, Wen A, Chin AT, Koss CA, Bacchetti P, Metcalfe J, Gandhi M. Quantifying isoniazid levels in small hair samples: A novel method for assessing adherence during the treatment of latent and active tuberculosis. PLoS One. 2016 May 18;11(5):e0155887. PMID: 27191185; PMCID: PMC4871544.
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