Modifications in IgG subclasses in the course of immunotherapy with grass pollen

In this study, we evaluated the evolution of IgG subclasses in the course of immunotherapy, and related this to the clinical evolution. We selected 226 adult patients with sensitivity to grass pollen alone, undergoing immunotherapy for 0-26 months. The following results may be highlighted: 1) IgG1 increased with immunotherapy and reached its peak at 6 months; 2) IgG2 increased significantly, reaching its peak after 24 months of treatment; 3) IgG3, however, did not present significant modifications in the course of immunotherapy; and 4) IgG4 was high in all patients undergoing immunotherapy compared to patients without hyposensitizing treatment, the peak being reached in the group of patients with the longest course of immunotherapy. Only IgG4 showed a positive and significant (p < 0.05) correlation with the degree of clinical recovery reached with immunotherapy.