A comparison of the clinical and immunological effects of an alum-precipitated five-grass extract with a conjugated two-grass extract in the desensitization of hay fever.

Thirty-nine patients with pollen hay fever were randomly allocated to receive either an alum-precipitated five-grass extract (Allpyral) or a two-grass conjugated extract (Conjuvac) prior to the 1982 pollen season. Efficacy was assessed by means of symptom scores, drug usage and specific IgE and IgG antibody response. Both nasal and eye symptom scores were significantly higher during the pollen season in those patients receiving Allpyral. Specific IgE and IgG measured after the pollen season showed similar rises in each group. Seven patients showed a marked elevation in specific IgE and nine a marked elevation in specific IgG, but no patient showed both. Those with a high specific IgE level tended to be younger. Symptom scores bore no relation to either specific IgE or IgG antibodies. Side-effects were mainly local and were equal in both groups.