Abstract
Lymphocyte proliferation in response to mitogens, phytohemagglutinin (PHA), concanavalin A, pokeweed, and/or specific antigens has been the method of choice for in vitro diagnosis of cellβmediated immune dysfunction. Recently, an assay to measure intracellular adenosine triphosphate (ATP) production in response to PHA has been developed that requires a shorter, overnight incubation. We compared a standard 5β to 7βday lymphocyte mitogen stimulation assay utilizing tritiated thymidine (^3^Hβthy) incorporation to one in which ATP production in response to PHA by CD4βpositive cells is measured in a luminometer that requires only 18β24βhr. A total of 20 patient samples suspected of having decreased cellβmediated immunity submitted for mitogen induced lymphocyte proliferation and 21 normal controls were tested in both assays. A comparison of these two methods has demonstrated that the screening ATP assay has a sensitivity at 24βhr of 100% in detecting decreased PHA induced lymphocyte proliferation at 5 days and a specificity of 85% in the samples obtained from normal controls. The data indicate that the ATP assay may be a useful screening tool for more rapid detection of blood samples with decreased cellβmediated immune responses. However, a positive screen should always be confirmed by ^3^Hβthy uptake using mitogens and recall antigens like candida and tetanus. J. Clin. Lab. Anal. 21:265β270, 2007. Β© 2007 WileyβLiss, Inc.