Elevated production of B cell chemokine CXCL13 is correlated with systemic lupus erythematosus disease activity.
BACKGROUND
B lymphocyte chemoattractant (BLC/CXCL13), a CXC chemokine, is involved in B1 and B2 cell trafficking for the activation of autoreactive T helper (Th) cells and autoantibody production in target organs during the development of lupus. CXCL13 can induce the trafficking of CXCR5+ T lymphocyte subset designated as follicular helper T lymphocytes (T(FH)) which are specifically involved in autoantibody production.


METHODS
We herein measured the plasma concentrations of CXCL13, B-cell-activating factor of the TNF family (BAFF), and T(FH)-cells-related cytokine IL-21 and cell surface expression of T(FH)-related receptor CXCR5 and IL-21R on CD4+Th and CD19+B cells in 35 systemic lupus erythematosus (SLE) patients and 23 sex- and age-matched control subjects (NC) using enzyme-linked immunosorbent assay and flow cytometry, respectively.


CONCLUSIONS
Plasma CXCL13, BAFF, and IL-21 concentrations were significantly higher in SLE patients than NC group (all p < 0.0001). Increase in CXCL13 concentration correlated positively and significantly with SLEDAI score in SLE patients (r = 0.399, p = 0.032). Cell surface expression of CXCR5 on Th and B cells and IL-21R on B cells was however significantly lower in SLE patients than controls (both p < 0.01). It may indicate that most differentiated T(FH) cells migrate out from circulation into lymphoid organ upon activation during the disease development of SLE.


CONCLUSIONS
The above results suggest that the elevated production of CXCL13, BAFF, and IL-21 may be associated with the function of T(FH) for the immunopathogenesis in SLE, and CXCL13 may serve as a potential disease marker of SLE.
Department of Chemical Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
C K
CK
Wong
Purple T Y
PT
Wong
L S
LS
Tam
Edmund K
EK
Li
D P
DP
Chen
Christopher W K
CW
Lam
D000328:Adult; D015703:Antigens, CD / Q000096:biosynthesis; D053264:B-Cell Activating Factor / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002465:Cell Movement / Q000276:immunology; D002478:Cells, Cultured; D054382:Chemokine CXCL13 / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D018450:Disease Progression; D005260:Female; D006801:Humans; D007378:Interleukins / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D054380:Receptors, CXCR5 / Q000235:genetics / Q000378:metabolism; D053655:Receptors, Interleukin-21 / Q000235:genetics / Q000378:metabolism; D000098546:Interleukin-21
D015703:Antigens, CD; D053264:B-Cell Activating Factor; D015415:Biomarkers; C095085:CXCR5 protein, human; D054382:Chemokine CXCL13; D007378:Interleukins; D054380:Receptors, CXCR5; D053655:Receptors, Interleukin-21; C505719:TNFSF13B protein, human; D000098546:Interleukin-21