Immunological interference of high dose corticosteroids.

High-dose corticosteroids (HDC) will influence cellular as well as humoral participants of the immune response. The lymphoid tissue will decrease in size and weight after prolonged treatment with HDC. Lymphocyte functions will be impaired. Reduced synthesis of B- as well as T-lymphocytes will be seen. The inhibitory effect on B-cell function can be observed both as decreased serum levels of immunoglobulins and as impaired binding of antibodies and complement to the cellular surface. Reduced T-cell function indicated by impaired stimulation by PHA and porkweed as well as by impaired lymphokinin effects on leukocyte migration inhibition has been reported. Reduced lymphocyte adherence to antigen and suppressed lymphocyte reaction have also been observed. Humoral factors involved in chemotaxis, opsonisation, phagocytosis, vascular permeability leading to leakage of fluid and cells and factors involved in lysis of antigens are impaired. This can be explained partly by the observed reduced complement activation via the alternative as well as the classical pathway in association with HDC therapy. Acute processes with increased vascular permeability and accumulation of leukocytes as impairing factors could be influenced beneficially by HDC therapy. This positive effect can be seen in treatment of septic shock or rejection of a transplant. However, if sepsis or rejection is not rapidly reversed, complications such as multisystem organ failure and bacteremia are prone to appear.