Immunotherapy with alginate-conjugated and alum-precipitated grass pollen extracts in patients with allergic rhinoconjunctivitis.

In order to compare the safety and the efficacy of two grass pollen extracts made from the same starting material, i.e. equal proportions of cocksfoot and timothy, a 3-year study was made on patients with hay fever. One product was a dialysed aqueous extract of pollens which was chemically conjugated to activated sodium alginate ( Conjuvac ). The other was a pyridine-extracted alum-precipitated crude extract (Allpyral). Forty patients with classical hay fever were admitted to the study. All gave positive result to prick and nasal/conjunctival testing with extracts of both cocksfoot and timothy grass. Thirty-five patients completed all 3 years of the study. Seventeen/eighteen Allpyral-treated and 17/17 Conjuvac -treated patients were subjectively improved. There was no significant difference in symptom scores between the two groups. Challenge tests showed a tendency to reduced sensitivity to allergen in the Conjuvac -treated but not in the Allpyral-treated group. The median values for specific IgG and IgE showed the same pattern of reaction as seen in earlier studies of pollen hyposensitization. There was, however, a greater increase of grass-specific IgG in the Conjuvac -treated patients. No serious adverse effects were seen in any of the treatment groups, but there were slightly fewer side effects in the Conjuvac group.