been demonstrated in in vivo skin tests fig1 fig8 shows an immunodetection test which indicates that the chimeras qm1 and qm2 have lower ige binding capacity in allergic patients compared with the reactivity of the natural protein der p 2 this reduction in allergenicity was quantified by means of elisa inhibition with a mixture of sera of patients allergic to d pteronyssinus fig1 2500 times as much of the qm1 protein was required to achieve 50 inhibition than of the mixture of the two natural proteins it can therefore be inferred that it was 2500 times less allergenic than the natural proteins which would indicate a reduction in ige binding capacity to the mixture of the two natural proteins of more than 99 a more direct measure of the hypoallergenicity of the chimeras qm1 and qm2 was obtained by direct measurements of skin reactivity in 107 patients allergic to d pteronyssinus the data in fig1 show that the chimera qm2 had markedly reduced skin reactivity chimera qm2 on the other hand only produced positive reactivity in 5 patients a comparison of each distribution shows that the chimera qm1 has a mean wheal size 50 times lower than that observed for nder p 2 and 10 times lower than that observed for nder p 1 which would indicate a reduction in allergenic activity of 90 98 this was despite the higher dosages used for the hybrid proteins.