Failure to induce tolerance to mechlorethamine hydrochloride

Area of Science:

• Immunology
• Dermatology
• Pharmacology

Background:

• Contradictory findings exist regarding specific immunologic tolerance induction to mechlorethamine hydrochloride (HN2).
• Previous attempts to establish tolerance using various schedules have yielded inconsistent results.
• Mechlorethamine hydrochloride is a nitrogen mustard used in treating certain dermatological conditions.

Purpose of the Study:

• To re-evaluate the efficacy of a previously reported "tolerogenic" schedule for inducing specific immunologic tolerance to mechlorethamine hydrochloride.
• To determine if a pre-treatment regimen could prevent contact sensitization to topical mechlorethamine.
• To clarify the conflicting literature on mechlorethamine hydrochloride tolerance.

Main Methods:

• A cohort of patients received intravenous mechlorethamine hydrochloride (200 micrograms weekly for five weeks) as a pre-treatment.
• Following the pre-treatment, patients underwent topical therapy with mechlorethamine hydrochloride.
• A control group also received topical mechlorethamine hydrochloride, with sensitization rates compared between groups.

Main Results:

• In the test group, 5 out of 13 patients (38.5%) developed contact sensitization to mechlorethamine hydrochloride.
• One additional patient in the test group experienced a probable contact urticarial reaction.
• In the control group, 5 out of 13 patients (38.5%) also became contact sensitized to mechlorethamine hydrochloride.

Conclusions:

• The investigated "tolerogenic" schedule was ineffective in inducing specific immunologic tolerance to mechlorethamine hydrochloride.
• The pre-treatment regimen did not significantly reduce the rate of contact sensitization compared to the control group.
• Further research is needed to identify effective methods for inducing tolerance to mechlorethamine hydrochloride, if possible.