Investigators Detect Correlation Between Peripheral Lymphocyte, TB Skin Test Reaction

A strong correlation exists between the reaction of the tuberculin skin test and the peripheral lymphocyte when both meet the measles virus.

The similar responses of these in vitro and in vivo tests help explain the ability of measles to elicit false-negative TB reactions among children, according to State University of New York investigators.

The Small Lymphocyte  The small lymphocyte "has been the cell implicated in mediating delayed hypersensitivity," by many investigators, said Elizabeth M. Smithwick, MD.Recent studies of both tuberculin-positive and negative children provide "further evidence that some property of the peripheral lymphocyte is responsible for a positive skin reaction," Dr. Smithwick told the National Tuberculosis Association-American Thoracic Society.Lymphocytes of tuberculin-positive children differ from those of negative children in that a greater number undergo blastogenesis or other transformation in contact with PPD ( purified protein derivative).It therefore is possible to distinguish positive from negative reactors by tissue