Polymorphonuclear leukocyte chemotaxis in psoriasis: enhancement by self-activated serum

The chemotactic activity of polymorphonuclear leukocytes (PMNs) directed against serum was determined in a modified Boyden chamber assay. In a total of 176 experiments PMNs and sera from healthy controls were compared with PMNs and sera from patients with psoriasis. When PMNs from patients with psoriasis were confronted with psoriatic serum greatly enhanced chemotaxis was demonstrated. Non-psoriatic PMNs in the presence of psoriatic serum showed no enhancement. However, psoriatic PMNs in the presence of normal serum were chemotactically more active compared to non-psoriatic PMNs. Heat inactivation (56 degrees C, 30 min) reduced the chemotactic activity of all sera by nearly 50%. However in psoriatic sera the enhancement of chemotaxis was still present after heat treatment. The results indicate the presence of a functional abnormality of chemotaxis in psoriasis. This is likely to be caused by the in situ generation of chemotactically active fragments of complement. Experiments showing increased chemotactic activity of sera exposed to migrating PMNs support this concept.