In vivo deposits of fibrin, fibrinogen, plasminogen, complements and immunoglobulins were observed using immunofluorescent (IF) staining of psoriatic lesions. Deposits of fibrin were seen in either the horny layer or the dermal papillae. A linear cytoplasmic appearance of fluorescence in the psoriatic scales was a common pattern of the staining. "IFstaining of the psoriatic horny/layer for fibrinogen and plasminogen' yielded essentially the same pattern as those of fibrin and IgG.These findings suggest that some fibrinolytic processes may be associated with an immune reaction in psoriatic skin, although they be secondary phenomena.The autoimmune hypothesis concerning the etiopathology of psoriasis is largely based on the demonstration of serum autoantibody to stratum corneum and complement-mediated immune complexes in the superficial layers of the psoriatic epidermis. It has been shown by Krogh (1), Beutner et al. (2) and Jablonska et al. (3) that in psoriasis, as well as in healthy controls, circulating antibodies are present and reactive with the membrane of the horny layer cells. These antibodies are of complement binding type. The in vivo binding of either immunoglobulin or complement with horny layer cells has also been demonstrated in psoriatic lesions (2-5). Cormane et al. (6) have observed in addition the presence of various immunoglobulins in the nuclei of the parakeratotic cells. The deposits of various immunoglobulins and complements In psoriatic skin are also associated with the appearance of fibrin and fibrinogen (7-10).The objectives of the studies presented in this report were to demonstrate the association of a fibrinolytic process with the immune reaction in psoriatic skin.
MATERIALS AND METHODS
Case studiedEighteen cases, II males and 7 females, of common psoriasis with characteristic lesions and histologic changes were studied. The age of the patients ranged from 22 to 83 years, and the duration of the disease was from I to 14 years.
Immunofluorescent (IF) methodsThe biopsied skin specimens were quick-frozen, cut on a cryostat, air-dried without fixation and incubated with either antisera or FITC-labeled conjugates for 30 minutes at room temperature. Antisera and FITC-labeled conjugates were absorbed twice with mouse liver acetone powders and diluted to suitable concentrations before incubation. The direct IF method was utilized for the detection of IgG, IgM, PIc, c, activator (CsA), Clq and fibrin, while the indirect method was used to detect plasminogen, fibrinogen and fibrin degradation product (FDP) in the skin using FITClabeled antirabbit y-globulin antibody. The FITClabeled conjugates were purchased from Medical and Biological laboratories LTC and antiplasminogen, fibrinogen and FDP sera from Dakopatts and Behringwerke AG. The F -P molar ratio of the conjugates ranged from 1.0 to I. 78 and antibody concentrations were between 30 and 50,ulml. Blocking tests were performed on the serial sections using unlabeled antisera and antigens.