Detection of IgE-positive leukocytes by synthetic peptide and monoclonal antibodies

Aliakhnovich N.S., Janchenko V.V., Martinovich V.P., Golubovich V.P.

1 Vitebsk State Medical University, Vitebsk, Belarus
2 Institute of Bioorganic Chemistry of the National Academy of Sciences of Belarus, Minsk, Belarus
3 The Research company Resan, Vitebsk, Belarus

The aim: to assess the use of the synthetic peptide p137-142FcεRIα, the fragment of the FcεRI active site, in identifying the IgE+ cells, compared to monoclonal antibodies to IgE.
Materials and methods. The study involved 39 children, mean age of 11 [10.0; 12.8] years. 105 blood samples were received. For phenotyping blood cells we used a synthetic hexapeptide p137-142FcεRIα, FITC-labeled (NIKP “Resan” Belarus), and monoclonal antibodies to IgE, Mouse Anti-Human (FITC), the production of Thermo Fisher Scientific Inc. USA. To count the eosinophils number general blood analysis was conducted.
Results. No significant differences between the number of cells identified with the synthetic peptide and mAb were found (p = 0,2), the correlation between the IgE+-cells number identified by both methods was high (0.8). From the 105 samples in 51 (49%) – normal and in 54 (51%) - increased level of eosinophils (≥6%) was found. IgE+-cells number was higher in children with an increased level of eosinophils, than with normal eosinophils (p = 0,00). Correlation between IgE+-cells and eosinophils increased in samples with eosinophilia. In 68% of cases with a low level of eosinophils (0-3%), the level of IgE+ cells was above half of the medium: 3-3.5% at 30,000 cells.
Conclusions. Determining the cells bound IgE by a synthetic peptide p137-142FcεRIα, fragment of the active center of the high affinity receptor for immunoglobulin E, is not worse than standard method of determining, using monoclonal antibodies to IgE. Number of eosinophils in peripheral blood correlates with the amount of IgE+-cells. In children with eosinophilia IgE+ -cell number is higher than in children with normal eosinophils level. There is a higher correlation IgE+-cell number with the eosinophils number in case of eosinophilia. In 14% of cases the other IgE+-cells (except eosinophils) were dominant.