GERMLINE TET2 LOSS-OF-FUNCTION CAUSES CHILDHOOD IMMUNODEFICIENCY WITH LYMPHOMA PREDISPOSITION
Abstract
Background and Aims
The molecular dissection of inborn errors of immunity can help to elucidate non-redundant functions of key genes and pathways. We investigated three patients from two unrelated consanguineous families diagnosed with an autosomal recessive syndrome of combined immunodeficiency, manifesting as lymphadenopathy, hepatosplenomegaly, susceptibility to infections, and lymphoma in childhood.
Methods
Immunologic investigations included flow cytometric immunophenotyping, lymphocyte proliferation and apoptosis assays. Whole exome sequencing (WES) data were interrogated for rare, homozygous, predicted deleterious variants, and their pathogenicity was explored. Relevant assays of protein expression and enzymatic function were performed. Total blood DNA methylation and in vitro differentiation potential of patient-derived B-cells and induced pluripotent stem cells (iPSC)-derived haematopoietic cells were studied.
Results
WES revealed homozygous missense and nonsense mutations within Tet methylcytosine dioxygenase 2 (TET2), a known epigenetic regulator of gene expression; its somatic loss-of-function mutations are associated with myeloid and lymphoid malignancies. Mutated TET2 protein was either absent or enzymatically defective for 5-hydroxymethylating activity in vitro. DNA methylation in total blood was reduced. Both patients with the p.H1382R mutation and clinically significant autoimmunity showed defective lymphocyte apoptosis, consistent with autoimmune lymphoproliferative syndrome. Moreover, patient’s B-cells were unable to generate plasma cells and produce IgG. The haematopoietic potential of patients-derived iPSC was skewed towards the myeloid lineage. Patients’ lymphoma tissue revealed acquisition of somatic mutations in genes within the RAS signalling pathway.
Conclusions
In this study, we defined the molecular and clinical consequences of germline TET2 impairment in immunodeficient patients, leading to altered DNA methylation, B-cell maturation, skewed haematopoiesis, and development of lymphomas.
***J. Spegarova, D. Lawless, S. Savic, and S. Hambleton have contributed equally to this work.
WHIM SYNDROME IS ASSOCIATED WITH A HIGH INCIDENCE MALIGNANCIES MAINLY RELATED TO HPV- AND EBV- INFECTIONS
Abstract
Background and Aims
Warts, hypogammaglobulinemia, infections, and myelokathexis syndrome (WHIMS) is a rare combined primary immunodeficiency caused by gain-of-function mutations in the chemokine receptor CXCR4 gene. While the susceptibility to human papillomavirus (HPV) induced malignancy is established, the overall malignancy risk is less well characterized. We present here an update on the global incidence of malignancy in WHIMS based on a literature review and data from the French Severe Chronic Neutropenia Registry.
Methods
We analyzed retrospective cohort data from 14 patients diagnosed with WHIMS from the French Severe Chronic Neutropenia Registry and conducted a literature review in PubMed to identify all cases of WHIMS associated with malignancy.
Results
Five Registry patients developed malignancy at median age of 37 years. The 40-years rate of malignancy was 46% (95% CI 17-88%). We observed two HPV-induced vulvar cancers (one lethal), 2 lymphomas (one bone, one skin lymphoma) and one basal cell carcinoma. In the literature, malignancy was reported in 12 reports (excluding our data) mainly in the 3 rd and 4 th decades. Malignancies included Epstein–Barr Virus (EBV) associated lymphoproliferative disorders, cutaneous B-cell lymphoma, melanoma, HPV oral squamous cell carcinoma, and multiple cases of HPV-related genital and anal cancers. In total, 8 cases of malignancy were linked to HPV and 3 to EBV. The CXCR4 variant Ser338* (c.1013C>G) was present in 6 WHIMS patients with malignancy reported in the literature.
Conclusions
Immunocompromised WHIMS patients are at high risk of malignancy, mainly HPV induced followed by lymphoma which is frequently EBV related.
GASTRIC CANCER IS THE MOST LETHAL COMPLICATION IN CVID: DATA FROM ITALIAN PID CENTRES AND PROPOSAL FOR A NEW SCREENING ALGORITHM
Abstract
Background and Aims
CVID is a heterogeneous disorder characterized by hypogammaglobulinemia, poor vaccine responses, and defects of memory B-cells. In addition to increased susceptibility to sinopulmonary infections, autoimmunity and granulomatous disease, an increased prevalence of lymphoma and of gastric cancer (GC) has been observed. Risk factors and surveillance strategies for GC in CVID are unclear.
Methods
Overall and GC incidence rates were evaluated in 455 CVID patients regularly followed up in three Italian Centres from 1993 to 2017 and compared with age-adjusted incidence rates in the Italian Cancer Registry database.
Results
CVID patients showed an increased cancer incidence for all sites combined (Obs = 133, SIR = 2.4; 95%CI = 1.7–3.5), due to an excess of non-Hodgkin lymphoma (Obs = 33, SIR = 14.3; 95%CI = 8.4–22.6) and of GC (Obs = 25; SIR = 6.4; 95%CI = 3.2–12.5) (Fig.1). H.pylori was significantly related to GC (OR=5.3, 95%CI=1.1–24.8, p=0.042). In contrast to other reports, GC was the leading cause of death in CVID. Standardized mortality ratio indicated a 10.1-fold excess mortality in CVID with GC. CVID developed GC 15 years earlier than the normative population, but they had a similar overall survival. Only CVID diagnosed at early GC stage survived >24months (Fig.2). Stomach histology performed before cancer onset showed atrophic gastritis, intestinal metaplasia or dysplasia. CVID patients might progress rapidly to advanced cancer stage as shown by patients developing III-IV stage within 1 year from an endoscopy negative for dysplasia.
Conclusions
Based on this large case series of GC in CVID we proposed a new screening program for CVID
INCIDENCE, TREATMENT AND OUTCOME OF MALIGNANCIES IN PATIENTS WITH ATAXIA TELANGIECTASIA IN A RETROSPECTIVE SINGLE CENTER STUDY.
Abstract
Background and Aims
Ataxia telangiectasia (A-T) with mutations in ATM caused a broad multi-systemic disease with an increased susceptibility to malignancies. The lack of immunological surveillance and disturbed cell regulative capacity of ATM protein predispose to malignancy.
Methods
In a retrospective single centre study of 66 A-T patients, we observed 14 cases of oncological diseases in 13 patients (20%) at a median age of 9 years (range 2-38 years); including Non-Hodgkin lymphoma (NHL; n=8), leukaemia (n=3), Hodgkin disease (n=1), hepatocellular carcinoma (HCC, n=1) and meningioma (n=1). The NHL group consisted of B-NHL (n=4), T-NHL (n=1), DLBCL (n=2); and NK-cell lymphoma (n=1).
Results
Immunology assessment of patients suffering from oncological diagnoses revealed T-lymphopenia with low CD3+T cells (median 705/µl; N>1000), naïve CD4+cells (median 33/µl; N> 200) as well as marked B-lymphopenia (median 83/µl; N>150). IgA deficiency was observed in 6/13 (46%). Five patients received treatment as per protocol, while seven patients were treated by individualized regimens using dose modifications and/or monoclonal antibody treatment (nivolumab n=1, brentuximab vedotin n=1, rituximab n=3). At last follow-up, two patients were on rituximab (remission). One patient had stopped nivolumab due to disease progress. Two patients had completed their treatment remaining in long-term remission. Death occurred in 8 patients (61%) due to malignancy progress and/or complications of chemotherapy, whereas A-T patients without malignancies showed a mortality rate of 11%.
Conclusions
This study provides details on malignancy type, immune profile, treatment regimens and outcome of A-T with and without malignancies. Our data highlight the substantial need for novel preventive and curative treatment options for malignancies in A-T.
CVID-ASSOCIATED TUMORS: CZECH NATIONWIDE STUDY FOCUSED ON EPIDEMIOLOGY, IMMUNOLOGY AND GENETIC BACKGROUND IN A COHORT OF PATIENTS WITH CVID
Abstract
Background and Aims
Common variable immunodeficiency (CVID) is one of the most frequent primary immunodeficiencies (PIDs) manifesting with increased susceptibility to infections and immune dysregulation. There is also higher risk of malignancies including lymphomas and gastric cancers. Here, we present results of the Czech national multicentric study focused on epidemiology, immunology and genetics in patients with CVID, who developed malignancy.
Methods
A cohort of 295 CVID patients was followed up for 3070 patient-years. SIR (Standardized Incidence Ratio) and RR (Risk Ratio) were calculated to determine the risk of cancer development, to assess predictive value of comorbidities respectively. Furthermore, we performed immunophenotyping of lymphocyte subpopulations and Whole exome sequencing (WES) in all patients with lymphoma.
Results
Twenty-five malignancies were found in 22 CVID patients. The risk for malignancy was 6 times higher in CVID patients compared to the general population. Lymphomas and gastric cancers were the most common malignancies. Immune thrombocytopenic purpura (ITP) was the significant negative prognostic factor with 3-times higher risk for tumor development. Post-treatment T and B cell lymphopenia associated with worse prognosis was found in the majority of patients in contrast to NK cells, which were not affected. WES revealed CVID and well as tumor susceptibility associated genes such as CTLA4, PIK3CD, PMS2; BRCA1, RABEP1, EP300, KDM5A respectively.
Conclusions
There is significantly higher incidence of malignancies in CVID patients, particularly lymphomas and gastric cancers. The history of ITP was identified as negative prognostic factor. WES confirmed wide genetic heterogeneity including causal and modifying variants of CVID as well as tumor susceptibility associated genes.
HEMATOLOGIC MALIGNANCIES IN 30 CHILDREN AND ADOLESCENTS WITH ATAXIA TELANGIECTASIA: 20 YEARS OF NATIONWIDE EXPERIENCE IN FRANCE
Abstract
Background and Aims
About 25% of patients with ataxia telangiectasia (AT) develop malignancies before the age of 20. Guidelines for treatments are lacking. Our aim was to describe the management of hematologic malignancies in children with AT.
Methods
For this national retrospective study, all patients with AT who had leukemia or lymphoma before the age of 18 were included.
Results
Thirty children with AT treated between 1996 and 2016 in 16 pediatric centers were reviewed (10 large B-cell diffuse lymphoma; 7 Hodgkin lymphoma (HL), 4 Burkitt lymphoma, 2 T-NHL; 4 T-ALL, 2 B-ALL, 1 AML). Median age was 8.1 years. Five HL and four NHL were EBV+. Ten patients died in palliative care (older age, diagnosis before 2010). Twenty patients received chemotherapy including rituximab in 8 cases; main drugs doses were reduced in 16 cases. Immunoglobulin replacement, prophylactic antibiotics and nutritional support tended to improve tolerance. Complete remission (CR) was achieved for 17 patients but 3 relapsed. One patient developed B-NHL 3 years after HL and is on CR2. Eleven patients died of progression or relapse (n=4), AT-related complications in CR1 at 5.4 and 11.2 years (n=2), toxicity (n=5): 3 sepsis, 1 pneumocystis and 1 late renal failure in CR1 at 8.1 years. Nine patients were alive in CR with a median follow-up of 4.2 years (2.3-9.4).
Conclusions
A curative strategy may be offered in children with AT whose neurological condition is still preserved allowing a prolonged remission in half of them. Modalities of chemotherapies and supportive care were significantly adapted and this deserves specific guidelines.
AN INTRONIC DELETION IN MKL1 IS ASSOCIATED WITH HYPERPROLIFERATION OF B CELLS IN TRIPLETS WITH HODGKIN LYMPHOMA
Abstract
Background and Aims
Megakaryoblastic leukemia-1 (MKL1) is a coactivator of serum response factor that together regulate transcription of actin cytoskeleton genes. MKL1 is associated with hematologic malignancies and immunodeficiency, but its role in B cells is unexplored. Here we examined B cells from monozygotic triplets with an intronic deletion in MKL1, two of whom were previously treated for Hodgkin lymphoma (HL).
Methods
The impact of the intronic deletion in MKL1 was assessed by RT-qPCR, WB, Flow cytometry, microscopy and in vivo assays using EBV-transformed lymphoblastoid cell lines (LCLs) from the triplets and two healthy donors.
Results
While cells from the HL treated patients had a phenotype close to healthy controls, cells from the undiagnosed triplet had increased MKL1 mRNA, increased MKL1 protein, and elevated expression of MKL1-dependent genes. This was associated with elevated actin content, increased cell spreading, decreased expression of CD11a integrin molecules, and delayed aggregation. Cells from the undiagnosed triplet proliferated faster, displayed a higher proportion of cells with genomic instability, and formed large tumors in vivo. This phenotype was reversible by inhibiting MKL1 activity. Interestingly, LCLs from the triplet treated for HL in 1985 contained two subpopulations: one with high expression of CD11a that behaved like control cells and the other with low expression of CD11a that formed large tumors in vivo similar to cells from the undiagnosed triplet.
Conclusions
These results suggest that increasedMKL1 activity leads B cell transformation and HL pathogenesis. Moreover the triplets treated for HL have pro-oncogenic cells that re-emerged a long time after treatment.