Immune reactivity in subjects remaining tuberculin-negative after repeated BCG vaccination.

Thirty-four children of 12 years mean age having had 3 to 5 BCG vaccinations owing to tuberculin negativity, were subjected to cellular and humoral immune assays (tuberculin skin test, leucocyte migration test, lymphocyte transformation test, estimation of serum IgG, IgA, and IgM levels). It was found that nonreactivity may cease by the age of 11 to 12 years. At the time of study 21 of the 34 children were already tuberculin-positive and only 13 failed to react to 5 TU. The studies confirmed the presence of combined immune deficiencies (negative tuberculin test, negative leucocyte migration test, abnormal immunoglobulin levels) as well as of changes confined to the individual immunoglobulin classes. In the case-history recurrent febrile diseases were found to occur more frequently between the 1st and 6th year of life than between 6 and 12 years of age. It is suggested that nonreactivity to tuberculin results from a congenital partial cellular immune deficiency.