Differential expression of CCL19 by DC-Lamp+ mature dendritic cells in human lymph node versus chronically inflamed skin.

De novo formation of lymphoid tissue is one of the characteristic features of chronic inflammation. The formation of T cell-mature dendritic cell (DC) clusters has been previously demonstrated in chronically inflamed skin infected with Candida albicans. A functional similarity was also found between chronic inflammation and the T-cell zone of lymph nodes (LNs), since a substantial fraction of phenotypically mature DCs in both tissues expressed CCL22 (macrophage-derived chemokine; MDC) and were closely surrounded by memory-type T cells expressing its receptor, CCR4. To analyse the nature of T cell-mature DC interactions further in chronically inflamed skin and LNs, the present study focuses on another chemokine system, namely CCL19 (EBI1 ligand chemokine; ELC), CCL21 (secondary lymphoid tissue chemokine; SLC) and their shared receptor, CCR7. RT-PCR analysis revealed expression of CCL19, CCL21, and CCR7 at high levels in LNs and at low levels in inflamed skin. Using immunohistochemistry, the majority of DC-Lamp(+) mature DCs in the T-cell area of LNs expressed CCL19 and were surrounded by CCR7(+) naïve-type lymphocytes, while CCL21 was expressed in reticular stromal cells and vascular endothelial cells. Very few mature DCs in LNs were found to express CCR7. In contrast, the majority of DC-Lamp(+) mature DCs in inflamed skin were totally negative for CCL19 and were surrounded by CCR7(-) memory-type T cells. Furthermore, CCL21 expression in the inflamed skin was detected in dermal lymphatic endothelial cells and rare CCR7(+) mature DCs were mostly seen within the lymphatic vessels. In normal skin, on the other hand, no cells immunoreactive for CCL19, CCL21, or CCR7 were found. The present study thus reveals a striking difference in the function of mature DCs between LNs and chronically inflamed skin.

Katou F ，Ohtani H ，Nakayama T ，Nagura H ，Yoshie O ，Motegi K ... -  《JOURNAL OF PATHOLOGY》

Augmented expression of secondary lymphoid tissue chemokine and EBI1 ligand chemokine in Crohn's disease.

Kawashima D ，Oshitani N ，Jinno Y ，Watanabe K ，Nakamura S ，Higuchi K ，Arakawa T ... -  《-》

Anatomic localization of immature and mature dendritic cell subsets in dermatomyositis and polymyositis: Interaction with chemokines and Th1 cytokine-producing cells.

Page G ，Chevrel G ，Miossec P 《ARTHRITIS AND RHEUMATISM》

Paired synovium and lymph nodes from rheumatoid arthritis patients differ in dendritic cell and chemokine expression.

The aim of this study was to compare the cellular composition and organization of rheumatoid (RA) synovium, which has several of the characteristics of lymphoid organs, with lymph nodes. To clarify further whether RA synovium can be classified as an ectopic lymphoid organ, paired RA synovium and lymph node (LN) tissues from 11 patients were compared in terms of T-cell-B-cell and germinal centre (GC) organization, dendritic cell (DC) subsets, and chemokine expression. Tonsil, a normal secondary lymphoid organ, was used as a tissue control. In paired RA LN and synovium, more follicular DC-positive GCs were observed in LN, but when observed in synovium, they shared the same T-cell-B-cell organization and mean GC size. In LN, a predominance of mature DC-LAMP-positive DCs of myeloid (CD11c-positive) or lymphoid (CD123-positive) origin was observed, whereas paired RA synovium was characterized by the relative accumulation of immature CD1a-positive DCs. In the same way, CCL19-CCL21/CCR7, a chemokine/chemokine receptor complex involved in mature DC migration, was more frequently seen in LN than in paired RA synovium. In synovium, such expression was associated with lymphoid follicle formation, with or without a GC. Conversely, CCL20, a chemokine involved in immature DC migration, was expressed in RA synovium and tonsils but not in paired LNs. In conclusion, although similarities were observed, this study, using paired samples, indicates that the RA synovium lacks some of the features that are characteristic of a lymphoid organ.

Page G ，Miossec P 《JOURNAL OF PATHOLOGY》

Cutting edge: secondary lymphoid-tissue chemokine (SLC) and CC chemokine receptor 7 (CCR7) participate in the emigration pathway of mature dendritic cells from the skin to regional lymph nodes.

Saeki H ，Moore AM ，Brown MJ ，Hwang ST ... -  《JOURNAL OF IMMUNOLOGY》