Cluster versus conventional immunotherapy in patients allergic to Dermatophagoides pteronyssinus: A controlled study of in vivo and in vitro parameters

We designed a cluster schedule of immunotherapy for patients allergic to De rmatophagoides pteronyssinus which showed good safety and clinical efficacy . Here we compare the in vivo and in vitro changes with those of a conventi onal schedule in a controlled trial Sixty-three patients were randomized as follows: 29 were treated with the cluster schedule, 15 with a conventional schedule and 19 received no immunotherapy. A standardized extract was used . Changes in in vivo parameters (skin prick test and conjunctival provocati on test) and in in vitro parameters (IgE, IgG, IgG1 and IgG4 for the comple te extract, Der p 1 and Der p 2) were measured before immunotherapy (T-0), on reaching maintenance phase (T-1), and after 6 (T-2), 12 (T-3) and 18 mon ths of maintenance (T-4). Cutaneous reactivity showed a significant decreas e from T-1 in both the cluster and conventional schedules, and conjunctival reactivity was also significantly lowered from T-1 in these groups. Specif ic IgE decreased and specific IgG, IgG1 and IgG4 increased significantly fr om T-1 in the cluster and conventional schedules. Neither of these paramete rs showed any changes in the group without immunotherapy. In conclusion, ou r cluster schedule induced changes in cutaneous and conjunctival reactivity and in immunological parameters that were similar to those achieved with t he conventional schedule; these changes did not appear in patients who did not undergo immunotherapy.