Immunoglobulin and beta 2-microglobulin concentrations in bronchoalveolar lavage of children and adults

Immunoglobulins play an important role in the pulmonary host defense, but little information is available about immunoglobulin and beta 2-microglobulin concentrations in the lung of normal children. Using bronchoalveolar lavage (BAL,) we have studied immunoglobulin and beta 2-microglobulin levels in 30 children 3-15 years old undergoing elective surgery for nonpulmonary illnesses and in 15 healthy adult volunteers. BAL was performed with 3 x 1 ml/kg of body weight normal saline through an endotracheal tube after induction of anesthesia in children and under local anesthesia in adults. Similar concentrations of IgA and IgG were found in BAL fluid of children and adults even though serum levels were lower in children. As comparable results were obtained for albumin, a serum-derived protein, these data suggest that the permeability of the alveolar membrane is higher in children. IgE and IgM were detected in BAL fluid in only a fraction of children, beta 2-microglobulin levels were higher in both blood and BAL fluid of children. These data provide the first reference data for immunoglobulin and beta 2-microglobulin in children and can serve as a basis for future studies of children with pulmonary diseases.