Humoral and cell-mediated immune responses to dog dander and hair in asthmatic children.

Dog dander and hair (DDH) specific IgA and IgG antibodies from serum samples of 202 asthmatic children aged from 4 to 15 years were measured by enzyme-linked immunosorbent assay. The results were compared with clinical history, and with allergy tests (skin prick test, provocation test and RAST) using the same DDH extract. A blood sample for the in vitro lymphocyte stimulation test was obtained from 40 children, and a nasal secretion sample for analysis of the local DDH-specific IgA, IgG and IgE antibody levels was collected from 35 of them. In children of dog-keeping families, higher serum levels of DDH-specific antibodies, especially IgE antibodies, were observed if the dog had been in the home already during the first years of the child's life. The serum levels of DDH-specific antibodies, however, did not correlate with the degree of the present exposure to dogs. The serum levels of DDH-specific IgA and IgG antibodies did not correlate with each other, with the levels of specific or total IgE, or with the results of skin prick or provocation test. The serum levels of DDH-specific IgA were highest in children who were subjectively most sensitive to dogs. Nasal levels of DDH-specific IgE correlated positively with serum specific IgE levels. The correlation was weaker between nasal and serum titers of specific IgG, and not significant between nasal and serum IgA antibody levels. Specific IgE antibody levels were higher, while specific IgA and IgG antibody levels were lower, in nasal secretion from subjects with nasal symptoms on contact with dogs, when compared with subjects with other complaints (asthma, conjunctival or skin reactions). DDH-specific IgG levels correlated negatively with specific IgE level in the nasal secretion from subjects with a positive provocation test result, while the correlation was positive in subjects with a negative provocation test. The in vitro lymphocyte responses to DDH did not correlate with the results of allergy tests, or with the levels of DDH-specific antibodies in serum or in nasal secretion.