Monocyte function in psoriasis

Monocytes derived from the peripheral blood of psoriatic patients demonstrated a significantly higher phagocytic capacity (36 to 40%) for both ¹²⁵I-labeled Shigella flexneri and ¹²⁵I-labeled Staphylococcus albus compared with monocytes from healthy subjects. Monocytes from psoriatic patients showed 2- to 4-fold increase in bactericidal capacity against S. albus when compared with normal monocytes. However, the bactericidal capacity of monocytes from diphylline-treated patients did not differ from that of the control subjects. The antibody-dependent cellular cytotoxicity (ADCC) activity against EL₄ tumor cells was found to be similar in both psoriatic patients and control subjects. It is postulated that these abnormalities of monocyte function in psoriasis are caused by a decreased cAMP/cGMP ratio similar to the decreased cAMP/cGMP ratio found in the lesional epidermis of this disease. It seems therefore, that the psoriatic abnormality is not confined to only one type of cell, the epidermal cell.