IMMUNOLOGICAL ASPECTS OF CARDIOVASCULAR-DISEASES - IMPLICATION FOR TREATMENT

The immunological cardiovascular diseases are a very diverse group of clinical entities that generally are of either unknown aetiology or of unproven pathophysiology. Most of the conditions with a proven, or st rongly suspected, aetiology are caused by infections, with the best ex amples being acute rheumatic fever and Lyme disease. However, even wit h these diseases, the primary pathophysiological mechanisms have not b een irrefutably established. In addition to the importance of infectio us agents in the immunological cardiovascular diseases, other factors have been identified that are associated with or modify these diseases . These factors include age, genetic background and coexisting inflamm atory diseases. The proposed immunological mechanisms important in the immunological cardiovascular diseases include: (a) immune mimicry, in which antigens of an infectious agent crossreact with self antigens; (b) modification of self antigens by infections or other inflammatory processes; (c) introduction of self antigens to the immune system foll owing a traumatic or inflammatory event; and (d) dysregulation of an a utoimmune response. The immunological effector mechanisms include: (a) passive deposition of immunoglobulin or immune complexes in cardiovas cular tissues with resulting inflammation; (b) autoantibodies that dam age the cardiovascular system directly or indirectly; and (c) cell-med iated immune responses to antigens within the cardiovascular system. T he clinical diagnosis of the immunological cardiovascular diseases is facilitated by clinical criteria and by selective laboratory tests in certain diseases. Laboratory tests, other than histology, do not usual ly provide definitive answers but serve to confirm suspected diagnoses . The vague, often systemic, symptoms associated with many of the diso rders add to the clinical confusion of diagnosis. Despite the lack of clearcut aetiologies, the classification of these diseases does facili tate therapeutic decision making. This is particularly important since the prognosis of some of these conditions, such as acute rheumatic fe ver, Lyme disease, Wegener's granulomatosis, systemic necrotising vasc ulitis and temporal arteritis, is significantly improved by treatment. Classification schemes for vasculitis remain primarily descriptive, b ut are useful for dividing the entities into categories with similar r esponse to treatment. Significant progress and improvement in the trea tment of the immunological cardiovascular disorders await better defin ition of the aetiologies and primary pathophysiological mechanisms inv olved.