BACKGROUND: RTX, an anti-CD20 monoclonal antibody, added to chemotherapy has proven to be effective in children and adolescents with high-grade, high-risk and matured non-Hodgkin lymphoma. RTX leads to prompt CD19+ B lymphocyte depletion. However, despite preserved immunoglobulin production by long-lived plasmablasts after treatment, patients remain at risk of prolonged hypogammaglobulinemia. Further, there are few general guidelines for immunology laboratories and clinical feature monitoring after B cell-targeted therapies. The aim of this paper is to describe B cell reconstitution and immunoglobulin levels after pediatric B-NHL protocols, that included a single RTX dose and to review the literature. METHODS: A retrospective single-center study on the impact of a single RTX dose included in a chemotherapeutic pediatric B Non-Hodgkin Lymphoma (B-NHL) treatment protocols. Immunology laboratory and clinical features were evaluated over an eight hundred days follow-up (FU) period, after completing B-NHL treatment. RESULTS: Nineteen patients (fifteen Burkitt lymphoma, three Diffuse large B cell lymphoma, and one Marginal zone B cell lymphoma) fulfilled the inclusion criteria. Initiation of B cell subset reconstitution occurred a median of three months after B-NHL treatment. Naïve and transitional B cells declined over the FU in contrast to the marginal zone and the switched memory B cell increase. The percentage of patients with IgG, IgA, and IgM hypogammaglobulinemia declined consistently over the FU. Prolonged IgG hypogammaglobulinemia was detectable in 9%, IgM in 13%, and IgA in 25%. All revaccinated patients responded to protein-based vaccines by specific IgG antibody production increase. Following antibiotic prophylaxes, none of the patients with hypogammaglobulinemia manifested with either a severe or opportunistic infection course. CONCLUSION: The addition of a single RTX dose to the chemotherapeutic treatment protocols was not shown to increase the risk of developing secondary antibody deficiency in B-NHL pediatric patients. Observed prolonged hypogammaglobulinemia remained clinically silent. However interdisciplinary agreement on regular long-term immunology FU after anti-CD20 agent treatment is required.

Department of Clinical Immunology and Allergology St Anne's University Hospital in Brno and Faculty of Medicine Masaryk University Brno Czech Republic

Department of Pediatric Oncology University Hospital Brno and Faculty of Medicine Masaryk University Brno Czech Republic

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