Diagnosis of toxoplasmosis after allogeneic stem cell transplantation: results of DNA detection and serological techniques.
BACKGROUND
The biological diagnosis of toxoplasmosis after allogeneic hematopoietic stem cell transplantation (HSCT) is based on the detection of Toxoplasma gondii DNA in blood specimens or other samples. Serological testing is used mainly to define the immunity status of the patient before HSCT. The aim of our study was to examine the performance of polymerase chain reaction (PCR) and serological techniques in the diagnosis of toxoplasmosis after HSCT.


METHODS
Seventy patients underwent allogeneic HSCT from September 2004 through September 2006. DNA was detected by PCR, and immunoglobulin G and immunoglobulin M were detected by enzyme-linked immunosorbent assay.


RESULTS
The results of immunoglobulin G detection before allogeneic HSCT were positive in 40 (57.1%) of the patients and negative in 30 (42.9%). After HSCT, 57 patients (81.4%) had test results that were negative for immunoglobulin M and had negative results of DNA detection, without toxoplasmosis infection. Four patients (5.7%) had at least 4 samples with positive PCR results and/or test results positive for immunoglobulin M against T. gondii; toxoplasmosis was then confirmed by clinical symptoms. Nine patients (12.9%) with positive PCR results and 1 or 2 samples with test results negative for immunoglobulin M were considered to have asymptomatic T. gondii infection. Reactivation of latent infection was the cause of toxoplasmosis in 3 of the 4 patients, and toxoplasmosis occurred as a primary infection in 1 patient. The detection of specific anti-T. gondii immunoglobulin M was the only biological evidence of toxoplasmosis in 2 patients, and samples were positive for immunoglobulin M before PCR was performed in 1 patient.


CONCLUSIONS
Thus, after HSCT, all patients were at risk for toxoplasmosis; all patients who receive HSCTs should be followed up with biological testing that combines PCR and serological techniques.
Fricker-Hidalgo
Hélène
H
Parasitologie-Mycologie, Pôle Biologie, Centre Hospitalier Universitaire, Grenoble, France. hfricker-hidalgo@chu-grenoble.fr
Bulabois
Claude-Eric
CE
Brenier-Pinchart
Marie-Pierre
MP
Hamidfar
Rebecca
R
Garban
Frédéric
F
Brion
Jean-Paul
JP
Timsit
Jean-François
JF
Cahn
Jean-Yves
JY
Pelloux
Hervé
H
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D016054:DNA, Protozoan / Q000032:analysis / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D033581:Stem Cell Transplantation / Q000009:adverse effects*; D014122:Toxoplasma / Q000302:isolation & purification*; D014123:Toxoplasmosis / Q000175:diagnosis*; D014184:Transplantation, Homologous / Q000009:adverse effects*
D000913:Antibodies, Protozoan; D016054:DNA, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M