Screening tests for cell-mediated immunodeficiency diseases

As our knowledge of immunology has become more sophisticated we have had to alter our ideas of the etiology of many immune deficiency diseases. Indeed, current concepts now prevalent have led to reclassification of a number of disease entities. In order to keep our diagnostic efforts abreast of the information being generated by the extensive immunology research programs now in progress, the clinical laboratory has been required to offer a new array of sophisticated tests on a relatively routine basis. This article is intended to serve as a brief review of immunobiology and immunodeficiency diseases with an indepth coverage of specialized tests generally available at the large centers. With an understanding of the principles, procedures, and pitfalls of the tests carried out the laboratory scientist is in a better position to assist the clinician in reaching the correct diagnosis. The detailed review is concerned with methods available to separate, classify, and subclassify lymphocytes and thereby allow a categorization of immune deficiency diseases. Toward that end there is a discussion of surface markers, rosetting, mitogenic and antigenic responsiveness as well as lymphokine production. With a view to present day research tests that might eventually find their way into the armamentarium of the clinical laboratory in the future, there is brief discussion of the methods presently used to classify T-cells as helper, suppressor, or effector cells, assays of some of the lymphokines, and measurement of antibody synthesis in cell culture.