An immunohistochemical analysis of the deposited immunoglobulins or fibrinogen in parakeratotic psoriatic horny layer and pemphigus skin lesions

Extractable immune complex in soluble substances from psoriatic scales

Soluble substances of psoriatic scales (Pso-exts) were analysed immunologically to detect immune complex (IC) related to the immune reactions in psoriatic lesions and compared with extracts of scales from a patient with erythroderma due to pityriasis rubra pilaris (PRP-exts) as control. Immunoelectrophoretically IgG, IgA and C3 were detected in Pso-exists, but in PRP-exists only IgG was seen as immunological reactive substances. When analysed by Sephadex G-200 column chromatography, IgG and IgA eluates were found in Pso-exts with a molecular weight of more than 200,000 daltons. By Raji cell assay, the IgG and IgA eluates were shown to have IC characteristics and they were the IC composed of IgG-IgA, which was also confirmed using anti-IgG affinity chromatography. The IC seemed to be binding the epidermal proteins as antigen. These findings suggest that deposits of immunoglobulins and complement in the stratum corneum of psoriatic lesions are not just secondary to the underlying inflammation in the dermis but that the IC detected is related to the immune reactions in psoriatic lesions.

Assessment of anti-stratum corneum antibody titres in pustulosis palmaris et plantaris

Titres of anti-stratum corneum (SC) antibodies, determined by an indirect immunofluorescence (IF) technique, were significantly higher on average in pustulosis palmaris et plantaris (PPP) and pompholyx than in normal controls. By a complement IF technique, the antibodies fixed complement (C3) in high titer in PPP, but to a much lesser degree in pompholyx and normal controls. Direct IF microscopy studies showed the deposition of IgG and C3 in the SC in some of the biopsy specimens of the pustular lesions. These findings suggest that in PPP anti-SC antibodies may be involved at least in part in activation of the complement system and the subsequent accumulation of polymorphonuclear leukocytes.

Immunofluorescence in psoriasis: studies of immunoglobulins, complement deposits, and three membrane markers

Sixteen psoriatic patients and 11 control subjects were investigated by immunofluorescence for skin immunoglobulins (IG) and complement (c) deposits and for keratinocyte membrane markers with anti beta 2 microglobulin (beta 2 m) antibodies (Ab), Con A, and pemphigus Ab. IG and/or c deposits were almost constant in involved epidermis. Three patterns were associated: (1) parakeratotic nuclear (dots-dashes), (2) stratum corneum (SC) intercellular (lamellar pattern), (3) vascular (granular or linear deposits in papillary dermal vessels). In uninvolved epidermis nuclear or vascular deposits could occasionally be present but intercellular pattern was never found in SC. Control specimens were always negative. The three surface markers investigated (beta 2 m, Con A receptor, Pemphigus antigen) could be demonstrated on psoriatic keratinocytes with only slight differences in distribution when compared with controls. Thus, by this methodology no important abnormality could be found in psoriatic keratinocyte membrane antigens.

A further study on the mechanism of deposition of plasma protein in psoriasis scale

To clarify the mechanism underlying the deposition of plasma protein in the psoriatic horny layer, extracts of psoriasis scale treated with fibrinolysin and acid citrate buffer were examined using electrophoresis and immunoelectrophoresis. Each extract showed electrophoretic and immunoelectrophoretic pattern similar to that of normal human serum, although the albumin-glublin ratio was lower than that of normal human serum. Extract after fibrinolysin treatment showed larger amount of substances than that after acid citrate buffer treatment. In each extract, high concentrations of fibrin-degrated products were found; fibrinogen was absent. These findings suggest that in the main mechanism of the deposition of plasma protein nonimmunological processes are involved, as revealed by our previous study with an immunohistochemical method, and that some fibrinolytic process occurs in psoriatic lesions.

Microvascular leakage of plasma proteins after short-term PUVA treatment

The transcapillary escape rate of albumin (TERalb) i.e., the fraction of intravascular albumin, that passes to the extravascular space per unit time is a parameter of the leakage of macromolecules from the total microvasculature. In this study TER alb was measured before and after PUVA treatment to psoriatic patients to study functional alterations in the microvasculature induced by the treatment. Short-term PUVA treatment caused a statistically significant increase in TERalb in 7 out of 8 patients (p less than 0.05). This seems to be a functional equivalent to the morphological changes in the dermal capillary of psoriatic skin and the ultrastructural changes in the dermal vessel walls described after PUVA treatment. It suggests, that the amorphous perivascular masses described in the psoriatic skin after PUsult of increased vascular permeability.

Immunopathology of psoriasis

Immunofluorescence (IF) studies by the direct and indirect methods demonstrate immunoglobulins and complement bound in vivo in psoriatic scales. The IF pattern is comparable to that of stratum corneum antibodies (SCAb) bound in vitro on specific substrate, as visualized by the indirect IF method. Formation of immune complexes can be responsible for the "squirting papilla" phenomenon, and conversion of the stratum corneum - which is normally an inaccessible antigen - into its reactive form seems to be brought about by proteases of polymorphonuclear leukocytes. Stimulation of protease production by polymorphonuclears appears to be an important factor in the pathogenesis of psoriasis. The stratum corneum of the epidermis is probably the target, and becomes an antigen for SCAb present in the circulation.