The effect of Goeckerman therapy on interferon in serum and suction blister fluid from patients with psoriasis.

An infectivity inhibition micromethod was used to detect interferon (IFN) in sera and suction blister fluids from 35 patients with untreated psoriasis vulgaris. IFN (greater than or equal to 16 units/ml) was detected in 56% of the sera (median 25 units/ml), in 77% of the suction blister fluids from lesional skin (median 35 units/ml) and 33% of the blister fluids from unaffected skin (median 10 units/ml). IFN levels were significantly higher in blister fluids from lesional skin than from unaffected skin (P less than 0.05) indicating local IFN production. Results of characterization experiments indicated the presence of both acid stable and acid labile IFN-alpha as well as IFN-gamma in sera and blister fluids. After Goeckerman therapy, IFN was detected in 91% of the sera (median 89 units/ml), in 90% of the blister fluids from lesional skin (median 50.5 units/ml) and in 72% of the blister fluids from unaffected skin (median 26.5 units/ml). The IFN levels in sera were significantly higher than in blister fluids from both lesional skin (P = 0.05), and unaffected skin (P = 0.001). Furthermore, after Goeckerman therapy the IFN levels in blister fluids from unaffected skin and in sera were significantly higher than those in untreated patients (P = 0.01 and P = 0.0001) respectively. The results indicate that UVB radiation induces systemic IFN production.