TNF-alpha Production Is Associated with Less Body Cell Mass in Women with RA

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J Rheumatol. 2004 Jan;31(1):23-9.

Tumor Necrosis Factor-alpha Production Is Associated with Less Body Cell

Mass in Women with Rheumatoid Arthritis.

Walsmith J, Abad L, Kehayias J, Roubenoff R.

Mayer USDA Human Nutrition Research Center on Aging, Tufts

University, Boston, Massachusetts, USA.

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.

CONCLUSION: Women with stable, medically well-controlled RA have lower

than normal BCM that is inversely associated with elevated TNF-alpha

production.

PMID: 14705214