Developing reliable methods to test the T-cell system may be important in the treatment of colon cancer patients with 5-fluorouracil/levamisole. In a pilot study we explored whether DNCB (dinitrochlorobenzene) skin testing correlated with plasma levels of soluble inter-leukin-2 receptor (sIL-2r) and soluble CD8 (sCD8) and, secondly, whether the application of DNCB had any influence on the production of sIL-2r and sCD8.Methods:
In 10 patients with advanced colon cancer and in 10 healthy volunteers, plasma levels of sIL-2r and sCD8 were measured before and 10 days after the application of 2 mg DNCB on the inner side of the forearm.Results:
As expected, colon cancer patients showed a depressed immune system compared to healthy volunteers (DNCB skin test:P=.005, sIL2r [medians 700 vs 295, P=.002], sCD8 [medians 158 vs 90, P=.03], M-W test). The plasma levels for sIL-2r and sCD8 were significantly lower in the skin-positive cases (P=.01 and P=.03, M-W test). However, a large overlap in plasma levels could be observed between the two skin categories. DNCB had no influence on the production of sIL-2r and sCD8; median change skin-negative and skin-positive -10 vs +25, P=.14, respectively; 48 vs 0, P=.32 (M-W test).Conclusions:
DNCB skin testing and plasma levels of sIL-2r and sCD8 seem to be equally useful in evaluating the T-cell system and can be used simultaneously.