Intramuscular gold decreases cytokine expression and macrophage numbers in the rheumatoid synovial membrane.
OBJECTIVE
Cytokines, released from mononuclear cells (MNC) are mediators of joint destruction in rheumatoid arthritis (RA). The mechanisms of action of gold salts used in the treatment of RA are unknown. The aim of this study was to investigate cytokine expression and intensity of MNC infiltrate in the RA synovial membrane (SM) following treatment with sodium aurothiomalate (SAT).


METHODS
Sequential blind needle biopsies were obtained at entry into the study and at two and 12 weeks after the start of SAT therapy in 10 patients with active RA. SMs were stained with a panel of monoclonal antibodies to assess cytokine expression (IL-1 alpha, IL-1 beta, TNF-alpha, IL-6, and GM-CSF).


RESULTS
There was a significant decrease in IL-1 alpha, IL-1 beta, IL-6 and TNF-alpha expression 12 weeks after treatment (p < 0.004, p < 0.002, p < 0.009 and p < 0.004 respectively). This was noted in the lining layer, the perivascular aggregates and the connective tissue areas. Detailed examination of the MNC infiltrate showed a significant reduction in inflammatory monocytes (MONO) in the lining layer at two weeks (p < 0.03). A decrease in the number of CD68+ macrophages (MAC) was noted in the perivascular and connective tissue areas at 12 weeks. No significant changes were observed in the number of T and B cells and blood vessels.


CONCLUSIONS
The results suggest that gold may suppress RA disease activity by diminishing MONO and MAC numbers and consequently monokine production in the SM.
Yanni
G
G
Department of Medicine, UMDS, Guy's Hospital, London, United Kingdom.
Nabil
M
M
Farahat
M R
MR
Poston
R N
RN
Panayi
G S
GS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D016207:Cytokines / Q000187:drug effects*; D005260:Female; D006052:Gold Sodium Thiomalate / Q000494:pharmacology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000187:drug effects; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis; D015850:Interleukin-6 / Q000032:analysis; D007958:Leukocyte Count / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013583:Synovial Membrane / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D006052:Gold Sodium Thiomalate; D016178:Granulocyte-Macrophage Colony-Stimulating Factor