Exposure to Candida albicans polarizes a T-cell driven arthritis model towards Th17 responses, resulting in a more destructive arthritis.
BACKGROUND
Fungal components have been shown very effective in generating Th17 responses. We investigated whether exposure to a minute amount of C. albicans in the arthritic joint altered the local cytokine environment, leading to enhanced Th17 expansion and resulting in a more destructive arthritis.


METHODS
Chronic SCW arthritis was induced by repeated injection with Streptococcus pyogenes (SCW) cell wall fragments into the knee joint of C57Bl/6 mice, alone or in combination with the yeast of C. albicans or Zymosan A. During the chronic phase of the arthritis, the cytokine levels, mRNA expression and histopathological analysis of the joints were performed. To investigate the phenotype of the IL-17 producing T-cells, synovial cells were isolated and analyzed by flowcytometry.


RESULTS
Intra-articular injection of either Zymosan A or C. albicans on top of the SCW injection both resulted in enhanced joint swelling and inflammation compared to the normal SCW group. However, only the addition of C. albicans during SCW arthritis resulted in severe chondrocyte death and enhanced destruction of cartilage and bone. Additionally, exposure to C. albicans led to increased IL-17 in the arthritic joint, which was accompanied by an increased synovial mRNA expression of T-bet and RORγT. Moreover, the C. albicans-injected mice had significantly more Th17 cells in the synovium, of which a large population also produced IFN-γ.


CONCLUSIONS
This study clearly shows that minute amounts of fungal components, like C. albicans, are very potent in interfering with the local cytokine environment in an arthritic joint, thereby polarizing arthritis towards a more destructive phenotype.
Rheumatology Research and Advanced Therapeutics, Department of Rheumatology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. rjmarijnissen@reuma.umcn.nl
Renoud J
RJ
Marijnissen
Marije I
MI
Koenders
Frank L
FL
van de Veerdonk
John
J
Dulos
Mihai G
MG
Netea
Annemieke M H
AM
Boots
Leo A B
LA
Joosten
Wim B
WB
van den Berg
D000818:Animals; D001168:Arthritis / Q000276:immunology*; D002176:Candida albicans / Q000276:immunology / Q000502:physiology*; D005434:Flow Cytometry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016133:Polymerase Chain Reaction; D058504:Th17 Cells / Q000276:immunology*