Objective   To observe the distribution of human splenic dendritic cells (DCs) with several DC markers and ultramicrostructural features of these DCs.    Methods   Spleen sample tissues of 35 individuals

including 30  patients after acute traumatic splenic rupture and 5 corpses after sudden death due to cardiac or cerebrovascular diseases were collected. The splenic dendritic cells in these sample sections were observed and analyzed by light microscopy

electron microscopy

and immunohistochemical staining with DCs markers including CD11c

CD205

CD209

S-100

CD1a

HLA-DR

CD80 and CD86.    Results   DCs were mainly distr

ibuted in 3 distinct regions

the T-cell zones

the B-cell zones

and the marginal zone in the spleen. In the marginal zone

DCs formed a ring surrounding the white pulps. CD209

+

DCs were nearer to the red pulp than CD11c

+

DCs and CD205

+

DCs. The CD11c

+

DCs

CD205

+

DCs and CD209

+

DCs accounted for about 4.19%

3.96% and 3.02%of all spleen mononuclear cells respectively. In normal human spleen

most DCs were immature and only a small amount were mature DCs

which were CD80 or CD86 positive and mainly distributed in the T-cells zones. Under an electron microscope

splenic DCs were large

slender or irregular in cell body

with several protrudes extending into the intercellular space. The nuclei were irregular in shape and depressed in surface with clear nucleoli. The cytoplasm was compacted or in low electron density and some organelles were seen.    Conclusion   Splenic DCs with different DC markers locate in different regions of the spleen. Most of them are immature

and only a small amount is mature.