Using a Boyden chamber technic, we measured the directed chemotaxis of polymorphonuclear leukocytes obtained from control subjects or
psoriasis patients when the leukocytes were placed in sera obtained from control subjects or
psoriasis patients. The samples from patients were obtained before
therapy and after 2 and 4 weeks of
etretinate administration. Compared with control sera, the sera from seven untreated
psoriasis patients significantly enhanced the chemotaxis of polymorphonuclear leukocytes from control subjects toward a
chemotaxin (p less than 0.05). After 4 weeks of
etretinate therapy, the chemotaxis-stimulating ability of the sera from
psoriasis patients was no longer significantly greater than that of the control sera. This decline in the chemotaxis-stimulating activity of our patients' sera preceded significant clearing of their
psoriasis. The levels of circulating
etretinate in the blood of our patients could not account for the reduction.
Etretinate therapy had no apparent direct effect on the chemotactic activity of polymorphonuclear leukocytes from the
psoriasis patients but may act in part by reducing the inflammatory effects of psoriatic sera.