Laboratory diagnosis and monitoring in chronic systemic autoimmune diseases

The testing done in the diagnostic immunology laboratory contributes to the management of patients with systemic autoimmune diseases. In these diseases the interaction between environmental factors and a genetically dysregulated immune system produces a continually variable level of disease activity. Improved techniques now allow the clinical scientist to assess the integrity of a patient's immune system and to ascertain qualitative or quantitative disturbances in its activation and expression. Cellular and humoral immunity may become independently activated or dysfunctional in certain disease processes, although the generation of amplifying proteins may result in the full clinical expression of immunity and autoimmune inflammation. Autoimmune diseases can, in part, be characterized according to the activation pattern of gene expression encoding the amplifying and proinflammatory cytokines. Modern therapy is increasingly aimed at determining ways to influence discrete elements of the immune apparatus; therefore, it is important to identify and characterize the patterns of expression of the immune system mediators serially in chronic autoimmune disease states. Newer diagnostic procedures stemming from observations in basic and clinical research are expanding the useful database on patients, but they must be carefully evaluated to prove their applicability and efficacy. Because blood samples are the best available specimens for testing, one must consider all the possible sampling problems and pitfalls of using results from peripheral blood to judge changes in function of the lymphoid system.