الفهرس 
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Abstract
One of the most prevalent parasite illnesses in humans is toxoplasmosis. The parasite is
mined by around one-third of the human population. Infection of an immune-competent human
host is usually asymptomatic. In immune-compromised patients, significant or life-threatening
complications such as encephalitis can arise as a result of either acute infection or reactivation of
infection acquired months or even years earlier. Particularly in the acute stage, toxoplasmosis is
thought to be a transfusion-transmissible illness among seropositive asymptomatic patients. Blood
transfusion infections are taken seriously, especially if they spread to people who get blood
transfusions often, such as patients with β-thalassemia. The presence of β-thalassemia associated
with several abnormalities of the innate immune system observed from early childhood. So,
thalassemia increases the risk for serious opportunistic infections. Patients with thalassemia are
burdened more by this infection since T. gondii is an opportunistic parasite that affects several
systems.
Human toxoplasmosis can be diagnosed by serological, histological, molecular, or a
combination of the aforementioned techniques. The most popular techniques are serological ones.
Toxoplasma gondii from bodily fluids and tissue is particularly identified using molecular
techniques for the identification of Toxoplasma DNA. Nested PCR and conventional PCR or
quantitative real-time PCR of repetitive DNA sequences could be used for diagnosis.
The aim of this work was to detect Toxoplasma gondii; serologically and molecularly in ß.
thalassemia patients and evaluate the effect of infection on some hematological parameters in these
patients. Blood samples were collected from ß. thalassemia attending Hematology Department,
Medical Research Institute. T. gondii IgM and IgG antibodies were serologically identified using
ELISA assays. Molecular diagnosis by Real-Time PCR was performed using specifically designed
primers amplifying 389 bp fragments of Toxoplasma genome. The age of patients ranged from 4
to 47 years with a mean of 19.5± 8.9 years. 53% of participants were aged ≤18 years, and 47%
aged >18. There were 31 males (13%) and 69 females (69%).
Identification of particular IgM and IgG antibodies using serology is the main currently
used method for diagnosis of toxoplasmosis. In the present study, 45 patients (45%) had anti-
Toxoplasma IgG antibodies with no detectable IgM antibodies. On the other hand, both anti-
Toxoplasma IgM and IgG antibodies were detected in 10 patients (10%), while only IgM-specific
antibodies were found in two instances (2%). The total seropositivity rate among patients was
57%.
Real-Time PCR analysis in the current investigation found Toxoplasma DNA in 20% of
the patients. . The obtained results showed that PCR has a sensitivity of 24.6%, specificity of
86.0% and positive predictive value (PPV) was 70.0, negative predictive value (NPV) was 46.25,
and area under curve (AUC) was 0.553. Positive PCR results were obtained in 100% of patients
(2 out of 2) with detectable anti-Toxoplasma IgM antibodies, 15.5% of patients (7 out of 45) with
detectable anti-Toxoplasma IgG antibodies, 50% of patients (5 out of 10) with detectable both anti-
Toxoplasma IgG and IgM antibodies. On the other hand, 16.2% of seronegative patients (6 out of
43) were PCR positive. There was a significant association between ELISA and PCR results.
Summary, Conclusion & Recommendations
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The agreement between PCR and ELISA for detection of T. gondii infection among
patients was studied. ELISA for anti-Toxoplasma IgG antibodies showed a Kappa index of 0.016
indicating poor agreement between the two methods. ELISA for anti-Toxoplasma IgM antibodies,
showed a Kappa index of 0.155 indicating slight agreement between the two methods. While
combined anti-Toxoplasma IgM &IgG antibodies ELISA results showed a Kappa index of 0.040
indicating poor agreement between the two methods
The association between some parameters and T. gondii infection was studied. According
to age categories, patients aged ≥18 years showed slightly higher T. gondii infection rate (72.3%)
compared to (58.1%) in the younger age group. As regards gender, females had nearly similar
infection rate as males (65.2% & 58.1%, respectively) with no statistical significance. Contact with
cats was associated with slightly higher infection rate (71.4% versus 60.8%). Similarly, patients
with positive history of consumption of undercooked meat had slightly higher rates of infection
(68.8 versus 60.3) with no statistical significance. Patients with an increased ESR level had higher
infection rate compared to patients with normal ESR, they had 2.2 time increased risk for infection
with no statistical significance. Patients with severe degree of anemia showed slightly higher
infection rate, compared to moderate degree and mild degree with no statistical significance. While
patients with ferritin value >1000 or <1000 of infection showed comparable infection rates, but
patients with normal ferritin showed lower rate of infection with no statistical significance.
As regard to blood transfusion type patients receiving washed blood showed higher
infection rate than filtered blood ( 65.9% versus 33.3%), although the difference was not
statistically significant (p= 0.073). As regards spleen status, patients with large spleen showed
slightly higher rate (68.8%) than patients with normal (61.8%) and removed spleen (58.8%),
however these differences were not statistically significant.