Immune Responses for Tuberculosis in the Infected Infant
Pp. 27-34 (8)
Dilvani O. Santos and Paulo R.Z. Antas
It is estimated that the lifetime risk of developing active disease after infection with
Mycobacterium tuberculosis in childhood is about 10%. Therefore, the human immune response to M.
tuberculosis infection prevents the development of illness in most people. Tuberculosis is contagious and
spreads through the air. Bacilli can subsequently enter the blood stream where they spread hematogenously
throughout the body. If not treated, each person with active tuberculosis disease can infect on average 10 to
15 people per year. The factors that allow for progression to active disease among infected persons are not
fully understood, however, they are likely immunologic, based on the increased rates of disease in persons
with varying forms of immune response. The source of infection for most children is an infectious adult in a
closed environment. This exposure leads to the development of a primary lesion in the lung witch spreads to
the regional lymph nodes. In the majority of cases, the resultant cell-mediated immunity controls the disease
at this stage. Risk of disease progression is higher in the very young (< 3 years-old) and in immune
compromised children. However, children with tuberculosis differ from adults in their immunological and
pathophysiological response in ways that may have important implications for the prevention, diagnosis and
treatment of this disease in the pediatric population.
Tuberculosis, Immune Response, Childhood, BCG.
Laboratorio de Biopatogenos e Ativacao Celular, Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Av. Barros-Terra s/n Valonguinho, zip: 24001-970, Niteroi, Rio de Janeiro, Brazil.