Toxoplasmosis after allogeneic stem cell transplantation--a single centre experience

Area of Science:

• Medical Mycology
• Infectious Diseases
• Hematology

Background:

• Toxoplasmosis is a rare but severe complication following allogeneic stem cell transplantation (SCT), often with a high mortality rate.
• Current diagnostic methods, primarily imaging and molecular techniques, may have limitations in early detection.
• Allogeneic SCT recipients are a vulnerable population susceptible to opportunistic infections.

Observation:

• Three cases of toxoplasmosis in 155 allograft recipients at Greifswald University Hospital are presented.
• Two cases of disseminated toxoplasmosis were diagnosed post-mortem in patients with multiple myeloma.
• One patient with acute myeloid leukemia developed cerebral toxoplasmosis, confirmed by cerebrospinal fluid PCR.

Findings:

• Conventional Toxoplasma gondii PCR showed limitations, with negative results in one case despite clinical suspicion.
• Real-time PCR targeting a 529-bp genomic fragment demonstrated higher sensitivity in detecting Toxoplasma DNA compared to conventional PCR.
• Toxoplasmosis was diagnosed late in the clinical course, highlighting diagnostic challenges.

Implications:

• Rigorous real-time PCR monitoring is recommended for high-risk SCT patients or those with suspicious symptoms.
• The findings suggest trimethoprim-sulfamethoxazole may be a preferred prophylaxis for Pneumocystis jirovecii pneumonia (PcP) over pentamidine in these patients.
• Improved diagnostic sensitivity could lead to earlier treatment and potentially better outcomes for SCT recipients at risk of toxoplasmosis.