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EG |
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| Egypt J Pediatr Allergy Immunol |
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2008 |
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6 |
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02 |
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69-76 |
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ESP - 75 |
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| Cell-mediated immunity in recent-onset type 1 diabetic children |
| Wafaa E. Ibrahim |
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Hala G. Mohamed |
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Hanan H. Ali |
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Esmail E. El-Sharnoby |
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| Background: The ability to suppress an immune response makes regulatory
T-cells (T-reg) an attractive candidate as a novel therapeutic agent for
treating autoimmune diseases. The mechanisms involved in maintenance of
peripheral tolerance include a specialized subset of regulatory-T-cells (Treg)
within the T-cell population. The CD4+ CD25+ T-cells may be
important in modulating the risk for autoimmunity. Auto-reactive cytotoxic
T-cells recognize peptide epitopes displayed on the beta cells surface in the
context of HLA class1 molecules. A population of CD8+ regulatory T-cells
characterized by expression of CD25 and FOXP3 have been identified and
induced in the human peripheral blood cells. The regulatory activity of these
cells is on autologous, antigen-reactive CD4+ T-cells in a cell contactdependent
manner. These findings provide an evidence for a new mechanism
for induction of immune regulation in human.
Objective: This study was aiming to assess the cellular immune parameters
including the percentage of CD4+, CD8+, CD4+/CD8+ ratio,CD4+CD25+,
CD8+ CD25+ lymphocytes, which may have its application in developing
immune therapy based tools for halting disease progression.
Methods: This study was conducted on 20 children of recent onset type 1
diabetes (disease duration <6 months) who were compared to 10 healthy
children. Each child was subjected to determination of CD markers by flow
cytometer.
Results: The patients group shows a significantly lower CD8+ lymphocyte
percentage (p<0.01) and significantly lower CD8+ CD25+ lymphocytes
percentage (p<0.05) compared to control group. The CD4+, CD4+/CD8+
ratio, CD4+ CD25+ was not significantly different (p>0.05) between the two
groups. A significant inverse correlation was found between CD4+ CD25+
T-cells and HbA1c percentage among patients group (p<0.05).Also a
significant difference in the percentage of CD4+ CD25+ T-cells was found
when patients with HbA1c<8% were compared to those with HbA1c>8%
(the latter group had significantly lower percentage of CD4+ CD8+ T-cells).
Conclusion: Type 1diabetes is characterised at its onset by a lowered
percentage of CD8+ and CD8+ CD25+ T-cells in peripheral blood, a normal
percentage of CD4+ and CD4+ CD25+ T-cells. There may be an inverse
correlation between percentage of CD4+ CD25+ T-cells at disease onset and
HbA1c level after three months. These data support the hypothesis that a
defect in function or deficiency in number of T- regulatory cells may affect
the pathogenesis of type 1 diabetes. |
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