Familial liability to complications after BCG vaccination.

Adverse reactions induced by vaccination with bacille Calmette-Guerin (BCG) were observed in three infants from two blood-related families. A boy and a girl showed disseminated BCG infection with a fatal course in the former case. The third infant had regional suppurative lymphadenitis. Cases of two other children from the same families are also described: a boy who received BCG vaccine after 5 y of age without complications, and a girl who has not yet been vaccinated. The clinical course and immunological evaluation of the reported cases suggest a congenital immunodeficiency of an unusual transient nature. The role of genetic factors in familial susceptibility to mycobacterial infection also needs to be taken into consideration.