Presence of chemotactic peptides other than C5a anaphylatoxin in scales of psoriasis and sterile pustular dermatoses.

A unique leukocyte chemotactic factor of around 12 kD molecular weight has been suggested to be responsible for the mechanisms involved in transepidermal migration of leukocytes observed in psoriasis and related sterile pustular dermatoses. Although we confirmed with radioimmunoassay the presence of a C5-cleavage product in the chemotactic fractions from psoriatic scale extract eluted by gel filtration HPLC, the neutrophil chemotactic activity demonstrated in the peak fraction was only partially inhibited by rabbit antiserum to human C5a, whereas that noted in the peak fraction, prepared from zymosan activated serum, was totally abrogated by the same treatment. Similarly the chemotactic fraction prepared from the scale extracts of other related pustular dermatoses were only partially inhibited with anti-C5a antiserum. These findings suggest that chemotactic peptides other than C5a also play a role in the transepidermal migration of leukocytes in these dermatoses.