Abstract
An IgE monoclonal protein is a rare finding. IgE multiple myeloma is uncommon, with only approximately 40 cases described. 1,2 The disease typically presents at older age and is characterized by a high frequency of Bence–Jones proteinuria and plasma cell leukaemia when compared with other isotypes of monoclonal proteins. 3 In this Letter, we report a transient IgE monoclonal protein as part of an oligoclonal pattern in a child with X-linked adrenoleucodystrophy during an Epstein-Barr virus (EBV) reactivation after haematopoietic stem cell transplantation (HSCT). The IgE monoclonal protein was part of an oligoclonal pattern with an IgG type λ, an IgG type λ or κ and an IgM type λ monoclonal protein (Figure 1). The fact that there were unmatched light chain bands on immunofixation prompted us to perform IgD and IgE immunofixation. The child suffered from X-linked adrenoleucodystrophy, treated with an HLA-matched unrelated HSCT. Conditioning regimen consisted of oral busulfan, fludarabine and antithymocyte globulin. Cyclosporine was used as graft-versus-host disease prophylaxis. Engraftment was achieved on day 14 post-HSCT with a complete donor chimerism. Six weeks post-HSCT routine EBV surveillance demonstrated an EBV reactivation. Cyclosporine was tapered and pre-emptive treatment with anti-CD20 antibodies was initiated with rapid reduction of EBV DNA. The transient oligoclonal monoclonal proteins were found during the EBV reactivation. To our knowledge, this is the first reported case of a transient IgE monoclonal fraction in a child.
Immunofixation analysis. Arrows indicate the monoclonal fractions (IgG, IgM, kappa, lambda and IgE)
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