Increased frequency of CD16+ monocytes and the presence of activated dendritic cells in salivary glands in primary Sjögren syndrome.
OBJECTIVE
In the salivary glands of patients with primary Sjögren Syndrome (pSjS) an accumulation of dendritic cells (DCs) is seen, which is thought to play a role in stimulating local inflammation. Aberrancies in subsets of monocytes, generally considered the blood precursors for DCs, may play a role in this accumulation of DCs. This study is aimed at determining the level of mature CD14lowCD16+ monocytes in pSjS and their contribution to the accumulation of DCs in pSjS.


METHODS
Levels of mature and immature monocytes in patients with pSjS (n = 19) and controls (n = 15) were analysed by flow cytometry. The reverse transmigration system was used for generation of DCs generated from monocyte subsets. The phenotype of DCs in pSjS salivary glands was analysed using immunohistochemistry. In vivo tracking of monocyte subsets was performed in a mouse model.


RESULTS
Increased levels of mature CD14lowCD16+ monocytes were found in patients with pSjS (mean (SD) 14.5 (5.5)% vs 11.4 (3.4)%). These cells showed normal expression of chemokine receptor and adhesion molecules. Mature monocytes partly developed into DC-lysosome-associated membrane glycoprotein (LAMP)+ (19.6 (7.5)%) and CD83+ (16 (9)%) DCs, markers also expressed by DCs in pSjS salivary glands. Monocyte tracking in the non-obese diabetic (NOD) mouse showed that the homologue population of mature mouse monocytes migrated to the salivary glands, and preferentially developed into CD11c+ DCs in vivo.


CONCLUSIONS
Mature monocytes are increased in pSjS and patient and mouse data support a model where this mature monocyte subset migrates to the salivary glands and develops into DCs.
Wildenberg
M E
ME
Department of Immunology, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. m.wildenberg@erasmusmc.nl
Welzen-Coppens
J M C
JM
van Helden-Meeuwsen
C G
CG
Bootsma
H
H
Vissink
A
A
van Rooijen
N
N
van de Merwe
J P
JP
Drexhage
H A
HA
Versnel
M A
MA
D000328:Adult; D000368:Aged; D000818:Animals; D015703:Antigens, CD / Q000097:blood; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000097:blood; D003713:Dendritic Cells / Q000276:immunology*; D058851:GPI-Linked Proteins; D006801:Humans; D007136:Immunoglobulins / Q000097:blood; D016130:Immunophenotyping; D051907:Lysosomal Membrane Proteins / Q000097:blood; D008562:Membrane Glycoproteins / Q000097:blood; D051379:Mice; D016688:Mice, Inbred NOD; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D017452:Receptors, IgG / Q000097:blood*; D012469:Salivary Glands / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000276:immunology*; D000097802:CD83 Antigen
D015703:Antigens, CD; D016207:Cytokines; D058851:GPI-Linked Proteins; D007136:Immunoglobulins; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D017452:Receptors, IgG; D000097802:CD83 Antigen; C428200:FCGR3B protein, human