S. Sato et al., Levels of interleukin 12, a cytokine of type 1 helper T cells, are elevated in sera from patients with systemic sclerosis, J RHEUMATOL, 27(12), 2000, pp. 2838-2842
Objective. To determine serum levels and spontaneous production by peripher
al blood mononuclear cells (PBMC) of interleukin 12 (IL-12), a potent induc
er of type 1 helper (Th1) T cells, in patients with systemic sclerosis (SSc
).
Methods. Serum IL-12 levels and spontaneous production levels of IL-12 in c
ulture supernatants from PBMC were examined by ELISA. Serum levels of IL-4,
IL-6, IL-10, and IL-13 and production levels by PBMC of IL-6 and IL-10 wer
e also examined by ELISA. Renal vascular damage was determined as a pulsati
lity index (PI) by color flow Doppler ultrasonography of kidneys.
Results. Serum IL-12 levels were significantly elevated in patients with SS
c (n = 62) compared with healthy controls (n = 20). Similarly, spontaneous
production levels of IL-12 by PBMC in patients with SSc (n = 47) were highe
r than those in controls (n = 20), Serum IL-12 levels did not correlate wit
h serum levels of any Th2-type cytokines such as IL-3, IL-6, IL-10, and IL-
13. However, spontaneous production levels of IL-10 by PBMC significantly c
orrelated with serum IL-12 levels in patients. Patients with elevated serum
IL-12 levels had the increased PI values more frequently than those with n
ormal IL-12 levels. Further, serum levels of IL-12 and production levels of
IL-12 by PBMC correlated significantly with the PI values in patients with
SSc.
Conclusion. These results suggest that the increased levels of IL-12 may re
late to the activation of Th1 cells in SSc and that IL-12 overproduction ma
y be associated with renal vascular damage.