A 5-Year Open-Label Follow-up of a Randomized Double-Blind Placebo-Controlled Trial of Intralymphatic Immunotherapy for Birch and Grass Allergy Reveals Long-term Beneficial Effects

BACKGROUND

Intralymphatic immunotherapy (ILIT) is a novel, faster alternative to conventional allergen immunotherapy (AIT). Few previous studies have evaluated its long-term effects. The objective of the present study was to complete a 5-year follow-up of a randomized double-blind placebo-controlled trial of ILIT for a combination of birch and grass allergens.

METHODS

Fifty-eight patients with allergic rhinitis were treated with either placebo or a combination of ALK Alutard Birch and Grass 1000 SQ-U administered in 3 intralymphatic injections at 1-month intervals. A year after the vaccination, the symptoms induced by nasal provocation were significantly reduced. After 5-6 years, 20 out of 26 actively treated patients were followed up with a nasal provocation test (NPT) and seasonal registration of the combined symptom and medications score (CSMS), IgE and IgG4 levels in blood, and immunological markers in blood and lymph nodes and compared with 13 unvaccinated controls.

RESULTS

The reduction in the NPT response with ILIT at year 1 could not be convincingly reproduced at year 5. The new CSMS scores were markedly lower among the previously treated patients than among the control group. Furthermore, grass-specific IgG4 was increased, grass-specific IgE decreased, FcεR1 on basophils was reduced, and the fraction of memory T-cells in lymph nodes increased.

CONCLUSION

The combination of seasonal clinical data and immunological parameters supports the notion of a long-lasting effect of ILIT. These data support the concept of ILIT as a good alternative to traditional AIT in pollen-induced allergic rhinitis.

Characterization of monoclonal anti-alpha 1-microglobulin antibodies: binding strength, binding sites, and inhibition of lymphocyte stimulation

Eleven monoclonal antibodies (MoAb) directed against the immunoregulatory plasma glycoprotein alpha 1-microglobulin were characterized. The MoAb were produced in mice immunized with a mixture of alpha 1-microglobulin homologues from man, guinea pig, rat and rabbit. Using radioimmunoassay, western blotting, affinity chromatography, and Scatchard analysis, the affinities and binding sites of the MoAb were analysed. All antibodies were more or less cross-reactive, but most showed a major specificity for one or two of the alpha 1-microglobulin homologues. None of the antibodies was directed against the carbohydrate moiety of alpha 1-microglobulin. Six of the MoAb had high affinity for the antigen and four of these were directed towards the same part of the molecule though differing in their species specificity. Five showed lower affinity for the antigen and were mainly directed towards epitopes on other parts of the molecule. Only some of the antibodies could block the proliferation of lymphocytes induced by human alpha 1-microglobulin. The blocking efficiency of the different antibodies was similar when tested on the stimulation of human or mouse lymphocytes, suggesting that the same part of the alpha 1-microglobulin molecule is responsible in both species. The magnitude of blocking by the different MoAb was not related to their affinities, emphasizing the importance of where on the alpha 1-microglobulin molecule, rather than how strongly, they bind. The binding of the strongest blocking antibody was shown to be directed to a C-terminal peptide of rat alpha 1-microglobulin, indicating that this part of alpha 1-microglobulin is important for the mitogenic effects. Thus the panel of anti-alpha 1-microglobulin MoAb should be a valuable tool for structural and functional studies of alpha 1-microglobulin.