Tumor necrosis factor-alpha production is associated with less body cell mass in women with rheumatoid arthritis.
OBJECTIVE
To examine the relationship between inflammatory cytokine production and body cell mass (BCM) in women with stable, medically well-controlled rheumatoid arthritis (RA).


METHODS
Case-control study of 20 women with RA and 20 healthy women matched for age, race, and body mass index (kg/m2). Tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta), and IL-6 production were measured by specific, non-cross-reacting ELISA of peripheral blood mononuclear cells (PBMC) cultured with and without 100 ng/ml of endotoxin. Total BCM was assessed by the reference method of whole-body counting of naturally occurring radioactive potassium-40.


RESULTS
Patients with RA were cachectic, with 14% less BCM (p < 0.001) and higher TNF-alpha production (p < 0.05) than controls. TNF-alpha production was inversely associated with BCM both without (r = -0.51, p = 0.03) and with (r = -0.57, p = 0.01) endotoxin stimulation in patients but not in controls. In multivariate linear regression models, these inverse associations remained significant after adjustment for age and physical activity. No association was found for IL-1beta or IL-6 production in these models.


CONCLUSIONS
Women with stable, medically well-controlled RA have lower than normal BCM that is inversely associated with elevated TNF-alpha production.
Walsmith
Joseph
J
Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111, USA.
Abad
Leslie
L
Kehayias
Joseph
J
Roubenoff
Ronenn
R
D000328:Adult; D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000378:metabolism*; D001823:Body Composition; D015992:Body Mass Index; D002100:Cachexia / Q000276:immunology / Q000378:metabolism; D016022:Case-Control Studies; D016207:Cytokines / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D016207:Cytokines; D014409:Tumor Necrosis Factor-alpha