[A novel liquid-phase enzyme immunoassay AlaSTAT for IgE antibody determination]

To determine whether a novel liquid-phase enzyme immunoassay AlaSTAT for allergen-specific IgE antibody determination can be used to measure the absolute amounts of serum IgE antibodies, we examined the amounts of anti-house dust (HD) and anti-mite IgE antibodies in sera of 32 HD-sensitized allergic asthmatics and 14 normal subjects by this immunoassay. The amounts of anti-mite IgE antibody in serum measured by this immunoassay were found to be consistent with those assessed by the difference in serum total IgE proteins before and after the absorption with mite allergen (the value determined by this immunoassay was 113% of the latter one, n = 4). Neither nonspecific IgE protein (50 to 10000 IU/ml) nor the heat-inactivated blocking serum affected the measurement of allergen-specific IgE antibody by the liquid-phase immunoassay. There were strong correlations between the values of anti-HD and anti-mite IgE antibodies by RAST and those by AlaSTAT (r = 0.90, p less than 0.001 and r = 0.86, p less than 0.001, n = 46, respectively). Our results indicate that the commercially available liquid-phase allergen-specific IgE enzyme immunoassay can be used to measure the absolute amounts of serum IgE antibodies without interference of nonspecific IgE protein or IgG blocking antibody.