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CD28 T lymphocytes and impact of viral infection in children
Nahla M Abd-Elaziz1, Ateyat A Ateya2, Amal Farouk3
Department of Clinical Pathology1 and Pediatrics2 , Faculty of Medicine for girls, Alazhar University
Clinical Pathology3, Faculty of Medicine,Ain shams University. email@example.com
Abstract: Background and aim: Cellular innate immunity plays a crucial role in viral infection. During active viral infection, viral pathogens modulate host immune system leading to immuno-senescence and immuno-suppression. Viral illness is usually controlled by a range of innate and adaptive immune-effector mechanisms. Little details are available on the frequencies, phenotype and function of antiviral T lymphocytes in pediatric populations. It was demonstrated that differentiation of CD28+ T lymphocytes into CD28 null T lymphocytes result in immuno-senescence and impairment of immune response. Our study aimed to know the link between viraemia, CD28 T lymphocytes and immuno-suppression during childhood. Patients and methods: This is cross sectional comparative study conducted at Al-Zahraa University Hospital, between April 2012 and July2012. The study included twenty acute viremic children, 20 chronic viremic children and 20 healthy control children. Using flow cytometry, we measured the percentage of the following phenotypes in the three studied groups, CD4 T helper lymphocytes, CD8 cytotoxic T lymphocytes and CD28+ T lymphocytes. In addition to the percentage of CD56+ natural killer cells. Results: We found that the mean percentage of CD28+ T lymphocytes of acute and chronic viremic groups was significantly lower than those of control group. Also, we observed significant difference between the three studied groups as regards CD4%, CD8% and CD4/CD8 ratio. Furthermore, chronic viremic group showed significantly lower frequency of CD28+ T lymphocyte than those of acute viremic group. Also, chronic viremic group showed strong correlation between the percentage of CD28+ T lymphocytes and CD4/CD8 ratio. Conclusion: The significant decrease in CD28+ naïve T lymphocytes of viremic group confirm the role of viremia in differentiation of CD28+ T lymphocytes into senescent CD28 null T lymphocytes. Also, striking reduction of CD28+ T cells in chronic viremic group revealed an association between chronic viremia and expansion of CD28 null T lymphocytes. Interestingly, the strong correlation between the percentage of CD28+ T lymphocytes of chronic viremic group and CD4/CD8 ratio which is considered as a predictor of immuno-efficiency clarify the interplay between viremia, CD28 molecules and immuno-suppression. Also, our study suggests that vaccine strategies may be available to support adaptive immune response against viral pathogens.
[Nahla M Abd-Elaziz, Ateyat A Attia, Amel Farouk..CD28 T lymphocytes and impact of viral infection in children. J Am Sci 2012;8(10):801-807]. (ISSN: 1545-1003). http://www.jofamericanscience.org. 108
Key words: CD28,antiviral lymphocyte, viral infection Full Text 108