Low levels of immunoglobulin A in children with intrinsic asthma: a possible protection against atopy

Immunoglobulin A and G (IgA, IgG) serum concentrations were detected in children with nonattergic/ intrinsic (36 children) or attergic/extrinsic asthma (43 children) and in age-matching control children (40 children). Asthmatic children with allergic asthma had tower IgA (1.36 +/- 0.54 g/L) and higher IgG (10.48 +/- 2.77 g/L) levels than the age-matching control children group (1.63 +/- 0.69 vs. 9.01 +/- 2.32 g/L). Children with nonallergic/intrinsic asthma had tower IgA (1.03 +/- 0.41 g/L) (p = 0.004) and IgG (8.38 +/- 1.93 g/L) (p = 0.001) levels than the attergic/extrinsic asthma group (1.36 +/- 0.54 vs. 10.48 +/- 2.77 g/L). Low IgA levels were found in children with nonallergic/intrinsic asthma and high IgG levels were found in those children with allergic /extrinsic childhood asthma. The hypothesis is that the increased incidence of asthma in the population may be caused by a decrease in childhood infections (hygiene hypothesis). Frequent infections in early life boost the immune system, stimulating Th1-type response in young children and reducing the risk of atopic diseases. Our hypothesis is that low IgA (and/or IgG) levels in our patients might be responsible for infection development among those children with nonattergic/intrinsic asthma. These infections stimulate the normal development of immune system in young children, reducing risk of atopy, so that those children do not get allergic /extrinsic childhood asthma. Intrinsic childhood asthma = nonallergic (nonatopic) childhood asthma. Extrinsic childhood asthma = allergic (atopic) childhood asthma. (C) 2003 Elsevier Ltd. All rights reserved.