Psoriasis and leukocyte chemotaxis.
Transepidermal migration of leukocytes, with resultant formation of microscopic or macroscopic sterile subcorneal pustules is a phenomenon characteristically noted in psoriasis and related sterile pustular dermatoses. It is natural to assume the presence of potent neutrophil chemotactic substances in the subcorneal portion of the lesional epidermis, because this location is the target of the in vivo leukocyte chemotaxis. In fact, crude psoriasis scale extracts show remarkably high neutrophil chemotactic and activating properties as compared with those of other non-psoriatic inflammatory dermatoses. We isolated a psoriatic leukotactic factor (PLF) having a molecular mass of around 12 kD, distinct from those common to other inflammatory changes involving the skin or those released by bacteria. Further analysis of PLF identified C5 cleavage fragments, together with other chemotactic peptides, such as those derived from monocytes. Likewise, potent low-molecular-mass chemotactic factors, including cell membrane lipid derived chemotactic factor, e.g. leukotriene B4, are also increased in psoriatic lesions, as in other nonpsoriatic inflammatory dermatoses. However, their activity to stimulate the generation of oxygen radicals in neutrophils was found to be much weaker than that of PLF. The peripheral blood leukocytes from active psoriatic patients show enhanced function in chemotaxis, phagocytosis, active oxygen production, and enzyme release; patients' sera contain substances such as anaphylatoxins that activate leukocyte function. Further research is required for clearer understanding of the series of events resulting in the leukocyte chemotaxis, as well as for the elucidation of the background immunoregulatory mechanisms.
D002465:Cell Movement; D002630:Chemotactic Factors; D002634:Chemotaxis, Leukocyte; D003167:Complement Activation; D003176:Complement C3 / Q000032:analysis; D015926:Complement C3a; D003181:Complement C4 / Q000032:analysis; D015934:Complement C4a; D003182:Complement C5 / Q000032:analysis; D015936:Complement C5a; D006801:Humans; D007962:Leukocytes / Q000502:physiology; D009504:Neutrophils / Q000473:pathology / Q000502:physiology; D011565:Psoriasis / Q000097:blood / Q000276:immunology* / Q000473:pathology
D002630:Chemotactic Factors; D003176:Complement C3; D003181:Complement C4; D003182:Complement C5; D015926:Complement C3a; D015934:Complement C4a; D015936:Complement C5a