title: Treatment assessment by monitoring parasite load in skin biopsies from patients with cutaneous leishmaniasis, using quantitative nucleic acid sequence-based amplification.
abstract: BACKGROUND
  Current diagnostic methods for cutaneous leishmaniasis (CL) have low sensitivity or are not useful for treatment follow-up. We previously described the quantitative nucleic acid sequence-based amplification (QT-NASBA) method as a sensitive and specific assay for detection and quantification of Leishmania parasites in skin biopsies. This assay could be a valuable instrument for monitoring response to treatment of CL and identifying treatment failures at an early stage.
  
  
  OBJECTIVE
  QT-NASBA results of skin biopsies at the end and 6 weeks after treatment from patients with proven CL on various treatment regimens were compared with clinical outcome.
  
  
  METHODS
  The QT-NASBA assay measured the parasite load in skin biopsies before, at the end and 6 weeks after treatment. The results were compared with treatment outcome (clinical cure, delayed healing response or treatment failure) up to 6 months after treatment.
  
  
  RESULTS
  In total, 137 skin biopsies were obtained from 53 patients. A positive QT-NASBA result 6 weeks after treatment was significantly associated with treatment failure/delayed healing up to 6 months (P < 0.001). The positive predictive value (PPV) was 100% and the negative predictive value (NPV) was 92% (95% CI 82-100%). QT-NASBA results at the end of treatment and clinical outcome showed a less significant association (P < 0.05), with a PPV of 46% (95% CI 16-75% and an NPV of 89% (95% CI 79-99%).
  
  
  CONCLUSIONS
  The QT-NASBA assay is a useful instrument to monitor parasite load in skin biopsies of patients with CL 6 weeks after treatment and can help to predict clinical outcome.
authors.affiliation: KIT Biomedical Research, Royal Tropical Institute, Amsterdam, The Netherlands. wfmeide@yahoo.com
authors.forename: W F
authors.initials: WF
authors.lastname: van der Meide
authors.forename: I
authors.initials: I
authors.lastname: Peekel
authors.forename: P P A M
authors.initials: PP
authors.lastname: van Thiel
authors.forename: H D F H
authors.initials: HD
authors.lastname: Schallig
authors.forename: H J C
authors.initials: HJ
authors.lastname: de Vries
authors.forename: J E
authors.initials: JE
authors.lastname: Zeegelaar
authors.forename: W R
authors.initials: WR
authors.lastname: Faber
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000981:Antiprotozoal Agents / Q000008:administration & dosage* / Q000009:adverse effects; D017679:Cryotherapy / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016773:Leishmaniasis, Cutaneous / Q000188:drug therapy / Q000469:parasitology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D021161:Self-Sustained Sequence Replication / Q000379:methods*; D012867:Skin / Q000469:parasitology*; D016896:Treatment Outcome
chemical_list: D000981:Antiprotozoal Agents