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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 47 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. |