Background: Serological diagnosis of toxoplasmosis in patients with haematological malignancy (HM) is
challenged by the impaired antibody response; meanwhile, molecular testing is necessary to demonstrate
reactivation.
Objective: Study of detection rates and risk factors for toxoplasmosis in HM patients using serological and
molecular methods.
Subjects and Methods: The study included 40 adult patients with HM, and 40 age and sex-matched healthy
individuals. Data on risk factors of toxoplasmosis were collected. Serologic testing for anti-Toxoplasma IgG
and IgM antibodies was performed using ELISA. Blood samples were examined molecularly for detection
of T. gondii 529re gene.
Results: Seropositive rate was significantly (P=0.003) higher among patients (75%) compared to healthy
individuals (42.5%). However, seropositive patients displayed lower anti-Toxoplasma IgG concentrations
compared to healthy individuals (P<0.05). Positive PCR results were obtained in 13 patients (32.5%) and
one healthy individual (2.5%) with a significant difference (P=0.0004). Seropositive patients showed
higher PCR positive rate (36.7%) compared to seropositive healthy individuals (5.9%) (P<0.05). No
statistically significant association was recorded between toxoplasmosis and the collected data for risk
factors.
Conclusion: Patients with HM are at high risk of toxoplasmosis and/or reactivation of latent infection. The
combination of serology and PCR is more accurate to reach a definite diagnosis. Follow-up is necessary to
prevent the development of life-threatening toxoplasmosis in these patients.