Contact dermatitis induced by glatiramer acetate

Flare up reaction during provocation test to glatiramer acetate in a patient with allergy to interferon beta1a

Glatiramer acetate (GA) is a synthetic amino acid polymer, used for relapsing-remitting multiple sclerosis. The most common adverse effect of GA is a skin reaction at the injection site with a probable IgE-mediated mechanism. We report a case of a 45-year-old woman with multiple sclerosis and urticaria to interferon-β1a, who underwent a challenge test to GA. She presented itching wheals at the intradermal sites. A month later the patient repeated the test and presented the same reactions of the first test. The next day she continued the test with subcutaneous injections. One hour later she presented a flare up of the reactions appeared during the previous 2 tests. No reactions appeared at the subcutaneous injection sites. The patient also presented dyspnea. Flare-up reactions are characterized by the reactivation of previously positive reactions to intradermal or skin tests triggered by patch testing and after systemic provocation with an allergen. The phenomenon is not common to drugs. The mechanisms involved in this reaction seem to be heterogeneous and are not completely understood. To our knowledge this is the first case of allergic reaction to GA manifested as a flare-up reaction during challenge test.

Immunological mechanisms underlying delayed-type hypersensitivity reactions to glatiramer acetate

BACKGROUND

Delayed-type hypersensitivity to glatiramer acetate is rare, and the underlying immunological mechanisms are not completely understood.

OBJECTIVE

To study the immunologic response in 2 patients with multiple sclerosis who developed maculopapular exanthema related with the administration of glatiramer acetate.

METHODS

The allergologic study included general blood tests, viral serologic tests, and skin tests (patch and intradermal tests). The immunologic study was performed in skin biopsy specimens by immunohistochemistry and in the peripheral blood by flow cytometry and the lymphocyte transformation test.

RESULTS

Skin test results were negative in both patients, and the diagnosis was confirmed by a drug provocation test. The evaluation of the acute phase showed an increase in the percentage of CD8 T lymphocytes (>50%) and the percentage of cells expressing skin-homing receptor (cutaneous lymphocyte-associated antigen) (>70%) and chemokine receptors (CCR4 and CXCR3) at T1. A positive proliferative response was observed in T lymphocytes (stimulation index [SI] = 3.5 in patient 1 and 3.59 in patient 2), especially the CD8(+) subpopulation (SI = 5.5 and 4.6 in patients 1 and 2, respectively), and NK lymphocytes (SI = 3.9 and 8.5 in patients 1 and 2, respectively) after glatiramer acetate stimulation.

CONCLUSION

This study demonstrates the important role of T(H)1 cells expressing skin-homing receptors in delayed-type hypersensitivity reactions to glatiramer acetate. A lymphocyte transformation test revealed a specific glatiramer acetate recognition by T lymphocytes and NK lymphocytes.