Abstract This study was performed to investigate changes in
the dendritic cells (DCs) frequency and phenotype in the
peripheral blood in Egyptian Type 1 diabetic children. Also to
study the level of B, T lymphocytes, activated T lymphocytes,
and costimulatory molecules expression on B lymphocytes.
Twenty five children with T1DM and 25 healthy controls were
enrolled. Flow cytometric detection of DCs, B-lymphocytes and
T-lymphocytes, CD19+CD80+, CD19+CD86+, CD19+HLADR+
and CD3+ HLA-DR+ was preformed. The frequencies of
monocytoid dendritic cells (mDCs) and plasmacytoid dendritic
cells (pDCs) were significantly decreased in diabetic patients
than the controls and the mDCs/pDCs ratio was significantly
higher in diabetic patients. The expression of costimulatory
molecules CD80 and CD86 on the entire DCs was significantly
higher in diabetic children. The frequency of pDCs was negatively
correlated with the age in diabetic patients and positively
correlated with the level of insulin C-peptide. The percentage of
CD80 expressing B lymphocytes and of activated T lymphocytes
was significantly higher in the patients. Dendritic cells are reduced
in number and display more mature phenotype in T1DM
children. The higher expression of CD80 on B lymphocytes and
activation of T lymphocytes may reflect the ongoing autoimmune
process in this disease. Modulation of the DCs could have
beneficial effect in T1DM.