Treatment assessment by monitoring parasite load in skin biopsies from patients with cutaneous leishmaniasis, using quantitative nucleic acid sequence-based amplification.
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.
van der Meide
W F
WF
KIT Biomedical Research, Royal Tropical Institute, Amsterdam, The Netherlands. wfmeide@yahoo.com
Peekel
I
I
van Thiel
P P A M
PP
Schallig
H D F H
HD
de Vries
H J C
HJ
Zeegelaar
J E
JE
Faber
W R
WR
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
D000981:Antiprotozoal Agents