Histological Characteristics of Ataxia Telangiectasia Associated Lymphoproliferative Diseases. Results of the French Registry of Primary Immune Deficiencies
Authors: Canioni Danielle , Mahlaoui Nizar , Andriamanga Chantal , Dubois d'Enghien Catherine , Jais Jean-Philippe , Fischer Alain , Hermine Olivier , Brousse Nicole , Stoppa-Lyonnet Dominique , Suarez Felipe 
Published: October 2019

Abstract
Introduction
Ataxia-telangiectasia (A-T) is a rare autosomal recessive disorder associated with mutations in the ATMgene and characterized by cerebellar ataxia, telangiectasia, immune defect, and a high incidence of lymphoid and solid cancers. We conducted a retrospective study of the patients with AT enrolled in the registry of the French National Reference Center for Primary Immune Deficiencies, in order to describe the incidence, subtypes, and outcomes of cancer and mainly of lymphoproliferative diseases (LPD) occurring in AT. Most of the LPD of this study were centrally reviewed by 2 expert hematopathologists.
Patients & Results
Sixty nine patients with cancers were identified among the 279 patients with AT of our cohort. Eight patients developed carcinomas, 8 acute leukemias, 3 T-cell prolymphocytic leukemias and 50 developed lymphomas. Among the lymphomas, 12 were classical Hodgkin's lymphomas (cHL), and 38 high-grade non-Hodgkin lymphomas (NHL, 26 of B-cell type, 4 of T-cell type, and 8 not phenotyped). We obtained a centralized histopathology review in 31 cases classified by pathology reports as cHL (n=6) and high-grade NHL (n=25). Cases were reviewed according to the WHO classification by H&E staining and immunohistochemistry. The presence of EBV was analyzed using antibodies to LMP and in situ hybridization for EBER. Concordance between the diagnosis established on pathology reports and the centralized review was excellent. All 6 cases of cHL were confirmed by the pathology review. The 25 cases initially diagnosed as high-grade NHL based on pathology reports fell into several WHO classification categories. Six corresponded to Burkitt's lymphomas (BL) and 12 to diffuse large B-cell lymphomas (DLBCL). Among the latter, 10 could be further classified according to cell-of-origin by the Hans algorithm as germinal center (GC, 2) and non-GC (8). Seven cases displayed polymorphic histological features reminiscent of post-transplant lymphoproliferative disorders (LPD), 5 polymorphic B cell LPD (pLPD), 1 with features of infectious mononucleosis (IM), another with features of plasmacytic hyperplasia LPD. EBV could be evaluated in 28 cases. All 6 cHL, 4 out of 11 DLBCL, all 5 pLPD, and the case of IM-like LPD were EBV positive by LMP and/or EBER staining. The 5 cases of BL that were evaluated were all EBV negative. Median age at diagnosis was 7.8 years [range 3 – 24], 14.9 [5.8 – 17.1], 12.2 [5.4 – 29] and 11 [6.3 – 17.7] for pLPD, cHL, BL and DLBCL respectively (p=ns). Median survival after diagnosis of lymphoma was 35, 8.6, 6 and 8 months for pLPD, cHL, BL and DLBCL respectively (p=ns). ATM mutation analysis was available for 20 cases (8 hypomorphic mutations, 12 loss-of-function mutations). There were no differences in age at diagnosis of lymphoma or survival according to the ATM mutation class or the EBV status.
Conclusion
B-cell malignancies including cHL and B-cell NHL are the most frequent malignancies in A-T and can be further classified as DLBCL, BL and cases with polymorphic features resembling post-transplant LPD. EBV seems to be associated with all cHL, approximately 50% of DLBCL and polymorphic LPD, but not with BL. The majority of DLBCL are non-GC type by immunohistochemistry. On this series of 31 patients, ATM mutation type was not associated with differences in type of lymphoma or outcome.

Disclosures
No relevant conflicts of interest to declare.