Introduction:

the development of inhibitors against factor VIII is the most serious complication of treatment in hemophilia A. Immune tolerance induction (ITI) enables the factor VIII concentrate to be used again for prophylaxis or treatment.

Objectives:

describe the experience with ITI in children of under 18 years of age with severe hemophilia A (SAH) in a health care provider.

Material and methods:

descriptive, retrospective study of children under 18 years of age with SAH, concentrations of FVIII inhibitors ≥ 5BU, who underwent ITI and full follow-up between 2009-2020. For ITI, we used plasma derived FVIII concentrate. The benefit is expressed as the success rate defined by the inhibitor’s negativization.

Results:

6 patients were included. Mean age at diagnosis of inhibitor 2,96 years, after 24,4 days of exposure (DAE) to FVIII concentrates. Mean ITI onset was 3,76 years and latency time from inhibitor diagnosis and ITI onset was 10,33 months.

Maximum peak of the pre ITI title was an average of 114,7 UB. Four patients started the ITI regimen with inhibitors titers less than 10 BU. The inhibitor titer negative in 8,2 months and in vivo recovery rate >65% was achieved with a mean of 15,7 months. The ITI was successful in 83% of the cases.

Conclusions:

ITI is highly successful in children with hemophilia A and high-titer inhibitors, as this case suggests. Since the response time is variable, the ITI must be individualized.

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