Objective: To evaluate whether immunomodulation at start of enzyme replacement therapy induces immune tolerance to recombinant human acid alpha-glucosidase (rhGAA) in patients with classic infantile Pompe disease. Study design: Three patients (1 cross reactive immunologic material negative, 2 cross reactive immunologic material positive) were treated with 4 weekly doses of rituximab, weekly methotrexate, and monthly intravenous immunoglobulin and enzyme replacement therapy at 40 mg/kg/week. Antibody titers were measured using enzyme-linked immunosorbent assay. Neutralizing effects on rhGAA activity and cellular uptake were determined and combined with pharmacokinetic analysis. Clinical efficacy was evaluated by (ventilator-free) survival, reduction in left ventricular mass index, and improvement of motor function. Results: Immunomodulation induced B cell depletion that was accompanied by absence of antibody formation in all 3 patients. Upon cessation of rituximab treatment, all 3 patients showed B cell recovery, which was accompanied by formation of very high sustained antibody titers in 2 patients. Neutralizing effects on infused rhGAA were low to mild/moderate. All patients were alive at study end, learned to walk, and showed (near) normalization of left ventricular mass index. Conclusions: Immunomodulation as recommended in the literature prevented formation of rhGAA antibodies only during B cell depletion but failed to induce immune tolerance in 2 out of 3 patients.

Cross-reactive immunologic material, Glycogen storage disease type II
dx.doi.org/10.1016/j.jpeds.2017.11.046, hdl.handle.net/1765/105264
Journal of Pediatrics
Department of Clinical Genetics

Poelman, E, Hoogeveen-Westerveld, M, Kroos-de Haan, M.A. (Marian A.), van den Hout, J.M.P, Bronsema, K.J, Van De Merbel, N.C, … Pijnappel, W.W.M.P. (2018). High Sustained Antibody Titers in Patients with Classic Infantile Pompe Disease Following Immunomodulation at Start of Enzyme Replacement Therapy. Journal of Pediatrics, 195, 236–243.e3. doi:10.1016/j.jpeds.2017.11.046