Occurence of Malignancies in Patients with Primary Immunodeficiencies: An Analysis of the French Primary Immunodeficency Registry
Authors: Suarez Felipe , Chapdelaine Hugo , Compain Laetitia , Mahlaoui Nizar , Andriamanga Chantal , Fischer Alain , Hermine Olivier 
Published: October 2019

Abstract
Abstract 1057

Background:
Primary immunodeficiencies (PID) are rare congenital disorders involving defects of the immune system. Aside from infectious complications, patients are at increased risk of malignant complications, which represent a leading cause of mortality in this context. The pathophysiology underlying malignant complications, especially lymphoid malignancies, in PID is not fully understood. The molecular mechansims of PID, that often involve lymphoid developent pathways, may also play a role in oncogenesis. A better understanding of the epidemiology of malignancies in PID may provide important insights in oncogenesis, particularly in lympomagenesis.

Material and methods:
French National Reference Center for Primary Immune Deficiencies (CEREDIH) has registered 4632 patients with PID as of July 2012. T-cell immunoficiencies and B-cell immodificencies reprensent 35.8% and 46.1% respectively. Patients with Ataxia-Telangiectasia and Severe Congenital Neutropenia were excluded frome the present analysis as they represent a more homogeneous group in terms of molecular pathophysiology and have been described elsewhere. T-cell immunodeficiencies comprise Severe combined immudoficiencies, Combined immunodeficiencies, other well defined T-cell immunoficiencies (including Wiskott-Aldrich Syndrome), and diseases of immune regulation (including X-linked lymphoproliferative disease and Autoimmune lymphoproliferative syndrome). B-cell immunodeficiencies include Agammaglobulinemia, Common Variable Immunodeficiency, Unspecified primary hypogammaglobulinemia, Selective IgA deficiency, Hyper-IgM symdrome and IgG subclass deficiency. Diagnostic class of PID, Age at diagnosis of PID, age at diagnosis of neoplastic complication, type of neoplasia, and survival were retrospectively colloected from the medical files. Non-melanomatous skin cancers and lymphoproliferative disorders occuring after allogeneic stem cell tranplantation were excluded from the analysis.

Results:
4632 patients with PID were analyzed. Two hundred and sixty seven patients developed 276 cancers (incidence 5.8%). One hundred and fifty seven patients developed lymphoid malignancies and 78 patients developed solid tumors (56.4% vs. 28.3% respectively). Compared to patients with B-cell PID, patients with T-cell PID had lower age at diagnosis of PID (5.5 [0–12.4] vs. 1.3–78]). Lymphoid malignancies, mainly high grade lymphomas were more prevalent in T-cell PID and PID diagnosed at a younger age (median age at diagnosis of PID for patients with lymphoid malignancies vs. solid tumors, 5.2 yr [0–85] and 37.5 [0–80] respectively, p<0,001). More than 75% of solid tumors occured in patients with B-cell PID with a median age of 45 yr. at diagnosis of cancer (p<0,001 compared to lymphoid malignancies for the entire cohort). Occurence of lymphoid malignancies had a major impact on mortality in patients with PID, with an overall survival (OS) of 24.7 yr [0.2–86] vs. 58.3 yr [0.2–90.8] for patients with solid tumors (p<0,001). The difference in OS between PID patients developing solid tumors was not statistically different than the whole cohort of PID patients. Both high and low-grade lymphomas were observed in patients with PID developing lymphoid malginancies. The majority of low grade-malignancies were oberserved in patients with B-cell PID.

Discussion:
PID bear a high risk of malignancies (5.8%). Solid tumors are observed mainly in B-cell PID and are diagnosed at an older age. Lymphoid malignancies are observed mainly in T-cell PID and B-cell PID diagnosed at a younger age, underlying a possible pathophysiological link between T-cell PID and a subset of B-cell PID.

Disclosures:
No relevant conflicts of interest to declare.