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Abstract Human Cytomegalovirus is a significant cause of morbidity and mortality in immunocompromised patients. After primary infection even if in apparent , the virus persists in the host for a long period of time and can be reactivated in immunosuppression, after massive blood transfusion, under intensive chemotherapy and tissue transplantation. The aim of this study is detecting prevalence of active HCMV infection among immunocompromised pediatric cancer patients, Comparing the sensitivity and specificity of quantitative Real time-PCR and qualitative PCR in the monitoring of active CMV infection. As well as their positive and negative predictive values.More over, this study can be helpful in Investigating the correlation between HCMV viral load in the clinical specimens and severity of the disease, according to the clinical HCMV scoring system as well as some clinical and hematological parameters that may lead to fatal outcome among cancer patients. In this study, 50 leukemic patients (40 ALL and 10 AML) and 30 normal control have been studied for the detection of the following assays; CMV IgG , CMV IgM by ELISA, conventional PCR and quantitative CMV by RT PCR assay.Briefly we can summarize our results in the following points: • Our selected patients were febrile and had signs of viral infections,also had organomegaly 35(70%) and chest infection 50(100%) .Median duration of febrile neutropenia was 26.5 day ranged (9-60 days) ,among half of our patients had more than the median value, Thirty percent of our patients had abnormal level of AST and 94 percent had abnormal level of LDH.The hematological parameters reveald that , 80% of patients had low hemoglobin, 22% low TLC , 46% lymphopenia, 84% neutropenia , 58% monocytopenia and 80% thrombocytopenia.these values were mointered in our patients. • The percentage of CMV positivity by conventional PCR in serum was (54 %and 46.7%) in both leukemic patients and control, respectively. On the other hand , the positivity of CMV in leukocyte was (38% and 40%) in leukemic patients and control group respectively, According to high positivity of CMV in serum, conventiol PCR was used as a gold standard technique. • Detection of CMV DNA by quantitative real time PCR, showing the positivity of CMV DNA 19/50(38%) in serum of leukemic patients, while in control group it was 14/30 (46.6%) with no significant difference between them (P value=0.446). Further more, the Determination of viral load among 19 positive HCMV DNA serum samples of patients and 14 of controls was done by quantitative RT PCR revealing a median viral load of 5.5x106 and 3.5x105 for patients andcontrols respectively, with a significant difference between the 2 groups (p=0.001). • Serological assays, on the other hand, showed that the Percentage of leukemic children positive for CMV IgM was significantly lower than that in the control group (11/50 22 % versus13/30 43.3%, P=0.044). CMV IgG was detected in 90% of leukemic and control groups respectively, (45/50 leukemias and 27/30 controls, p=1.00). • Presence of HCMV infection in sera of leukemia and control groups by serological and molecular assays is demonstrated. The results of qualitative PCR showed the highest sensitivity, specificity and accuracy compared to other assays(IgM,high IgG,quantitative PCR ) among leukemia group.Considering qualitative PCR assay is the golden standard assay for detection of active HCMV infection, efficacy of other different assays were evaluated. Sensitivity, specificity, PPV, NPV and accuracy of the applied diagnostic methods for CMV are demonstrated. Sensitivity of CMV IgM and quantitative assay was lower in leukemic patients compared to control (40% and 70% respectively for leukemic patients vs 85.7% and 100% respectively for control group). In contrast sensitivity of high titer IgG was higher in leukemic patients than control (80% vs 50% respectively). • The leukemic patients who were viremic and had high IgG titer were more associated with mucositis (P=0.06) though borderline, low count of TLC (<11950cells/cmm) (P=0.021) than those with positive IgM. Also, Presence of CMV viral load was significantly associated with lymphopenia (P=0.02).Presence of HCMV viremia was not associated with CMV disease ( p=0.967). • Reciver operating characteristic curve (ROC ) curve analysis was performed to identify leukemic patients who are at risk of development of severe CMV disease and preemptive therapy is required. The estimated area under the curve adjusted for CMV serum QPCR was 0.783 with statistical significance (P = 0.037) indicating proper adjustment. The cutoff DNAemia value was at 3520000 copies/µL; this viral load was the best value to discriminate between patients with high and low risk absolute lymphocytic count, with sensitivity and specificity equal to 80% and 67%, respectively. • In general,The results of the current study showed that severe CMV disease highly associated with the low survival of pediatric leukemia patients (P=0.002) also, the duration of febrile neutropenia (P=0.024), thrombocytopenia (P=0.024), lymphopenia (P=0.042), neutropenia (P=0.044) affected the survival status of these patients. |