An immunologic study of psoriasis.

Thirty-five patients with psoriasis and 18 normal controls were studied in order to assess the role of humoral immunity in psoriasis. Direct immunofluorescent study of skin biopsy specimens taken from the lesions revealed deposits of immunoglobulins (IgA, IgG, IgM) and complement components (Clq, C3), mainly in the stratum corneum. Deposits were also found in Munro's microabscesses, spongiform pustules of Kogoj, upper layers of the stratum malpighii, dermal blood vessels, and cells of the dermal inflammatory infiltrate. Uninvolved skin of the patients and normal controls revealed negative fluorescent results. There was a significant increase in the mean levels of IgA and IgG in patients with psoriasis, whereas IgM was within the normal range. The present study showed humoral abnormalities in psoriasis that may be involved in its pathogenesis.