[The immunology of psoriasis].

In recent years, numerous studies have reported the existence of multiple immune disturbances in psoriasis. Estimation of serum immunoglobulins shows an increase in IgA and a possible decrease in IgM. The percentage of psoriatic patients with an increased IgE (450 I.U./ml) is increased in comparison with the normal population. IgA levels in salivary secretions are markedly increased. There are anti-IgG antibodies as well as anti-IgG activity on circulating lymphocytes in 45 p. 100 of psoriasis sufferers. This anti-IgG activity has also been described by certain authors in the psoriatic epidermis. More recently, the abnormal presence of anti-stratum corneum auto-antibodies fixed on the corneal layer has been noted. Cell immunity explored by intra-dermal tests and by the DCNB test is little disturbed. However, certain studies have shown a dissociated deficiency in circulating T-lymphocytes. Finally, it is now well established that BW17, B13 and BW38 histocompatibility antigens are found with a high degree of frequency in psoriasis. The role of these immunological disturbances in psoriatic disease remains to be defined.