HYPOGAMMAGLOBULINEMIA AT DIAGNOSIS IS ASSOCIATED WITH INFERIOR SURVIVAL AND HIGHER RISK OF INFECTIONS IN DIFFUSE LARGE B CELL LYMPHOMA: A RETROSPECTIVE STUDY FROM SWEDEN

Abstract

Introduction: Low level of antibody production does not only increase the risk of infections, but also the incidence of malignancies, especially lymphoma. The primary aim of this study was to explore if hypogammaglobulinemia in untreated diffuse large B cell lymphoma (DLBCL) was associated with inferior overall survival (OS) or inferior progression free survival (PFS). Secondary aims were to assess the relationships between low immunoglobulins (Ig), other laboratory tests and infections. Methods: Using data from the Swedish Lymphoma Register (SLR), we identified all adult patients (18 years or older) diagnosed with DLBCL, receiving anthracycline-based curative therapy during year 2001–2015 in two health regions in southern Sweden (one university hospital and one region hospital). Data from the SLR were supplemented by patient record review, including data on baseline Ig levels and infections of CTC-AE grade 3–5 (in-hospital stay and intravenous antibiotics). Survival was analyzed by Kaplan-Meier estimates. Simple and multivariate linear regression were performed to determine relationships between laboratory tests and number of infections. Results: 596 patients were included, median age was 69 years (20–96), 57% were men, median OS 72 months, and median PFS 64 months. Median follow-up time for living patients was 106 months (62–117). 25% had low Ig, defined as any deficiency, 18% had low IgG, 37% lymphopenia and 13% both low Ig and lymphopenia. Hypogammaglobulinemia was associated with inferior OS (HR 1.4, 95% CI 1.0–1.9, p-value 0.018) and inferior PFS (HR 1.3, 95% CI 1.0–1.7, p-value 0.032). The combination of low Ig and lymphopenia aggravated OS (HR 1.2, 95% CI 1.0–1.2, p-value 0.023) and PFS (HR 1.2, 95% CI 1.0–1.3, p-value 0.002). Hypogammaglobulinemia was also associated with a higher number of infections (p-value 0.021), adjusted for International Prognostic Index (IPI) the associations weakened (p-value 0.097). The combination of low Ig and lymphopenia was not related to more infections than low Ig alone. Keywords: aggressive B-cell non-Hodgkin lymphoma, diagnostic and prognostic biomarkers No conflicts of interests pertinent to the abstract.