The distribution of peripheral blood dendritic cells assayed by a new panel of anti-BDCA monoclonal antibodies in healthy representatives of the Polish population

A growing number of studies are being performed on the role of dendritic cells (DCs) in the etiopathogenesis of various conditions. Therefore, it is extremely important to establish the best comparable methods for the determination of the absolute count of blood dendritic cells (BDCs) or their subsets, and the reference normal values for comparisons. The aim of our study was to assess a normal profile of BDCs in the non-cultured human blood of healthy Polish volunteers. BDCs were detected among peripheral blood mononuclear cells (PBMC) from 99 healthy people, aged 18- 56. Based on the panel of novel anti-BDCA1, BDCA2 and BDCA3 monoclonal antibodies (MoAbs), three main subpopulations of BDCs were distinguished: two myeloid types of BDCs, MDC1(BDCA-1+/ CD11c+ /HLA-DR+) or MDC2 (BDCA-3+/CD32-/CD64-/HLA-DR+), and a plasmacytoid subtype, PDC (BDCA-2+/CD123+/HLA-DR+). The number and percentage of BDCs were correlated with the age, gender, photosensitivity (phototype, minimal erythemal dose - MED) and morphological parameters of the healthy volunteers. BDCs represented 0.83% of the PBMC and the median total BDC number was 44.0 cell/ml. The total BDC number correlated with the WBC count (r=0.40; p<0.001) as well as with the lymphocyte and monocyte counts (r=0.20; p=0.045 and r=0.26; p=0.009, respectively). The median percentage of the MDC1 count (0.20%) was twice as high as the MDC2 count (0.10%). The median PDC count was 28.2 cell/ml, and these cells represented 0.50% of the PBMC. There was a positive correlation between PDC and skin photosensitivity (r=0.28; p=0.005). An inverse correlation between the PDC count and the age of the examined volunteers was also found (r=-0.22; p=0.029). Our study provides the first referential data on normal rates and counts of BDCs and their subpopulations, assessed by the new panel of anti-BDCA MoAbs, in healthy Polish subjects. The method used in the study allowed the determination of BDCs and their subset numbers in a relatively small blood volume.