[UV exposure, skin cancer and decrease in the ozone layer].

All over the world a remarkable increase in malignant tumors of the skin is reported. More than 90% of them are localized in areas of the skin exposed to sunlight. The incidence of malignant melanomas of the skin is tenfold higher today than 40 years ago.

Complement deposits in epidermal cells after ultraviolet B exposure.

Ultraviolet B (UVB) radiation is known to induce formation of sunburn cells (SBC) in the epidermis. Since it was unknown whether this process might be accompanied by complement (C) activation, we analyzed C-deposition in skin biopsies taken before and 24 h and 48 h after UVB exposure (fourfold minimal erythema dose or fourfold minimal phototoxic dose) from 14 patients (5 receiving potentially photosensitizing drugs and 9 without such medication) by immunohistology. Local C-activation was visualized by direct or indirect immunofluorescence staining with polyclonal antibodies against C3b, C3d, C5, C9 and monoclonal antibodies to C3b, C3d, C9 and neoantigens on the terminal complement complex (TCC).

Phototoxic erythema following PUVA treatment: independence of complement.

The effect of PUVA treatment on normal human serum (NHS), on isolated PMN, or on C3-deficient guinea pigs and congenic (C3-competent) control animals was tested. At a concentration of 0.1 or 1 mM/l 8-MOP and UVA doses of 5-30 J/cm2, PUVA failed to induce any detectable C3-cleavage in NHS.

[Complement-independent bulla formation in pemphigus vulgaris by IgG4].

In cryostat sections from lesional skin of a patient with pemphigus, a typical pattern of IgG deposits was detected at the epidermal intercellular space. However, there were no deposits of complement (C) components. By the highly sensitive APAAP technique using monoclonal antibodies, it was demonstrated that the IgG deposits consisted exclusively of IgG4.