Immunoglobulin levels in bronchoalveolar lavage fluid of children with chronic chest disease

The concentration and distribution of immunoglobulin isotypes (IgG, IgM, sl gA) and IgG-subclass levels (IgG-1-4) were measured in bronchoalveolar lava ge fluid (BALF) in 47 children with chronic chest disease (age range 1.0-9. 9 years) and 18 healthy controls (age range 1.0-6.25 years). Of these patie nts, 19 had nonallergic asthma (Group A), 19 suffered from recurrent pneumo nia or chronic bronchitis (Group B), and 9 patients had IgG-2 deficiency (G roup C). In all individuals, IgG was the predominant immunoglobulin in the lower res piratory tract, followed by ISA and IgM. In patients of Group A and B, IgG, IgM and IgA levels in BALF were significantly elevated when compared to co ntrols. Assessment of IgG-subclass concentrations in BALF revealed that. Ig G-l levels were increased in Group A and B when compared to controls (P < 0 .05). Since this difference could not be explained by difference in age, it is possibly due to the inflammatory process at the mucosal level. IgG-2 le vels were elevated in all patients except those with IgG-2 deficiency. IgG- 2 concentration in the IgG-2 deficent group was lower compared to controls (P < 0.005) and patients in Group A (P < 0.0005) and B (P < 0.005). IgG-3 l evels were elevated in asthmatics in group A compared to healthy controls ( P < 0.005). IgG-4 concentrations were the same in all study groups. Since IgG-subclasses in percentage of total IgG were similar in BALF and se rum, our results do not indicate a local production of any of the IgG-subcl asses in the respiratory tract. (C) 2000 Wiley-Liss, Inc.