Real-time PCR for diagnosis and follow-up of Toxoplasma reactivation after allogeneic stem cell transplantation using fluorescence resonance energy transfer hybridization probes.
Toxoplasma reactivation is a life-threatening complication of allogeneic stem cell transplantation. A poor prognosis is probably linked to a difficult diagnosis, based on the detection of evidence of parasites in tissue. We developed a real-time PCR test using fluorescence resonance energy transfer hybridization probes to detect and quantify Toxoplasma gondii DNA in serum. This PCR test gave reproducible quantitative results over a dynamic range of from 0.75 x 10(6) to 0.75 parasites per PCR mixture. Serial samples from four patients with toxoplasma reactivation were evaluated. Three patients had several consecutive PCR-positive samples which corresponded to </=0.75 parasites. These three patients became PCR negative during trimethoprim-sulfamethoxazole therapy but never developed clinically apparent toxoplasmosis. In contrast, one patient had an increasing PCR signal, from 1 to 396 parasites in 12 days, and developed cerebral symptoms. The parasite count decreased to 5 parasites in 3 days after pyrimethamine-clindamycin treatment. Real-time quantitative PCR is useful for diagnosis and follow-up of toxoplasma reactivation.
Laboratoire de Biologie Moléculaire, Hôpital Américain, BP 109, 92202, Neuilly, France.
J M
JM
Costa
C
C
Pautas
P
P
Ernault
F
F
Foulet
C
C
Cordonnier
S
S
Bretagne
D000328:Adult; D000818:Animals; D002648:Child; D015342:DNA Probes; D016054:DNA, Protozoan / Q000097:blood; D004735:Energy Transfer; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction / Q000379:methods*; D013050:Spectrometry, Fluorescence; D014122:Toxoplasma / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000469:parasitology; D014184:Transplantation, Homologous / Q000009:adverse effects
D015342:DNA Probes; D016054:DNA, Protozoan