Essentials Genetic predisposition to acquired thrombotic thrombocytopenic purpura (aTTP) is mainly unknown. Genetic risk factors for aTTP were studied by Immunochip analysis and replication study. Human leukocyte antigen (HLA) variant rs6903608 conferred a 2.5-fold higher risk of developing aTTP. rs6903608 and HLA-DQB1*05:03 may explain most of the HLA association signal in aTTP. Click to hear Dr Cataland's presentation on acquired thrombotic thrombocytopenic purpura SUMMARY: Background Acquired thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening thrombotic microangiopathy associated with the development of autoantibodies against the von Willebrand factor-cleaving protease ADAMTS-13. Similarly to what has been found for other autoimmune disorders, there is evidence of a genetic contribution, including the association of the human leukocyte antigen (HLA) class II complex with disease risk. Objective To identify novel genetic risk factors in acquired TTP. Patients/Methods We undertook a case-control genetic association study in 190 European-origin TTP patients and 1255 Italian healthy controls by using the Illumina Immunochip. Replication analysis in 88 Italian cases and 456 controls was performed with single-nucleotide polymorphism (SNP) TaqMan assays. Results and conclusion We identified one common variant (rs6903608) located within the HLA class II locus that was independently associated with acquired TTP at genome-wide significance and conferred a 2.6-fold increased risk of developing a TTP episode (95% confidence interval [CI] 2.02-3.27, P = 1.64 × 10 ). We also found five non-HLA variants mapping to chromosomes 2, 6, 8 and X that were suggestively associated with the disease: rs9490550, rs115265285, rs5927472, rs7823314, and rs1334768 (nominal P-values ranging from 1.59 × 10 to 7.60 × 10 ). Replication analysis confirmed the association of HLA variant rs6903608 with acquired TTP (pooled P = 3.95 × 10 ). Imputation of classic HLA genes followed by stepwise conditional analysis revealed that the combination of rs6903608 and HLA-DQB1*05:03 may explain most of the HLA association signal in acquired TTP. Our results refined the association of the HLA class II locus with acquired TTP, confirming its importance in the etiology of this autoimmune disease.
Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease characterized by recurrent chromosomal aberrations of prognostic significance. We aimed to evaluate the potential of the multiplex ligation-dependent probe amplification (MLPA) assay to detect genomic alterations in CLL. Highly purified (>90%) peripheral mononuclear CD19+ cell populations from 100 untreated CLL patients (pts) in early stage disease (Binet stage A) were included in this study. All samples were investigated by fluorescence in situ hybridization (FISH) for the presence of trisomy 12 and 17p13.1, 11q22.3, and 13q14.3 deletions. For MPLA analysis, DNA was amplified by means of two commercially available probes sets allowing the simultaneous screening of 56 genomic sequences. Overall, a high degree of concordance (95%) between MPLA and FISH results was found, if the abnormal clone was present in more than 30% of the leukemic cell population. The use of multiple MPLA probes allowed the fine-mapping of the 13q14 deletion and the identification of intragenic or small alterations undetected by FISH. Moreover, additional alterations in 2p24 (MYCN) (3 pts), 8q24 (MYC) (1 pt), 9p21 (CDKN2A2B) (1 pt), 1q21 (LMNA) (1 pt), and 6q25-26 (1 pt) regions not covered by a standard FISH assay were detected and all confirmed by FISH. Our data extend previously limited evidence that MLPA may represent a useful technique for the characterization of well-known lesions as well as the investigation of additional genomic changes in CLL.
Introduction Limited stage follicular lymphoma (FL) is usually managed with involved field radiotherapy (IFRT), although different approaches are currently carried out, ranging from watch and wait to combined treatment. RT on involved lymph nodes allows eradication of the disease only in 40-50% of patients. Anti-CD20 monoclonal antibodies (MoAb), widely used in advanced stage FL, are likely to be effective in reducing the relapse risk, although no scientific evidence of their role has been provided. The aim of this multicenter phase II prospective study was to evaluate the role of MRD in identifying patients unlikely to be cured by RT, for whom an immunotherapy-based consolidation could improve outcome. Methods 110 patients with stage I/II FL were enrolled. IFRT was administered to all patients at a dose of 24 Gy. Peripheral blood (PB) and bone marrow (BM) samples were centralized to the Italian FIL (Federazione Italiani Linfomi) MRD Network of EuroMRD-certified laboratories: the presence of a BCL2/IGH rearrangement was investigated at baseline in all patients by nested PCR (NEST) and RQ-PCR (RQ), the latter according to the EuroMRD guidelines. In patients BCL2/IGH+ at baseline by both NEST and RQ in BM and/or PB, MRD was analyzed in both tissues after IFRT and every 6 months over a three-year follow-up period. Patients with positive MRD by both NEST and RQ in BM and/or PB after IFRT or who became positive during the follow-up were treated with 8 weekly doses of the anti-CD20 MoAb ofatumumab. The primary objective of the study was to define the efficacy of immunotherapy in obtaining the disappearance of BCL2/IGH rearranged cells. Results Preliminary data are available for 107 patients, 57 males, 50 females. Median age was 55 years (29-83). 17% had G1 FL, 32% G2, 40% G3A, 11% NOS. The FLIPI score was 0 in 59% of patients, 1 in 35%, 2 in 6%. 69% of patients had inguinal site involvement. Despite a negative BM biopsy, at baseline 30% of patients (n=32) had a BCL2/IGH rearrangement (30 MBR, 1 MBR and mcr, 1 mcr) in the BM and/or PB; the concordance between compartments was 90%, with 10% of negative PB showing a positive BM. No significant differences were observed in relapse probability between patients with or without a molecular marker. All patients were submitted to IFRT and all obtained a clinical response, which was complete in 79 of the 101 evaluated patients (78%) and partial in 22 (22%). MRD evaluation after treatment revealed the persistence of BCL2/IGH rearranged cells in the PB and/or BM in 60% of patients. According to the design of the protocol, MRD-positive patients, either after IFRT (n=18) or in case of conversion to a positive signal during the follow-up (n=7), received 8 weekly administration of ofatumumab. A conversion to MRD negativity, evaluated in 23 treated patients, was obtained in 20 (87% - CI 65.1-97.1). This result was significantly superior to the expected 50%. One death occurred after IFRT, due to ischemic stroke. Adverse events likely correlated to ofatumumab occurred in 7/25 treated patients, consisting of infusion reactions in 5, leading to a permanent interruption of immunotherapy in 3. After a median follow-up of 18 months, all patients who achieved a MRD negativity with ofatumumab underwent a regular molecular follow-up and are still MRD-negative. Overall, clinical relapse or progression were observed in 17 patients: 13 (18%) among the 73 "no marker" patients; 2 relapses (16%) were observed among the 12 MRD-negative patients after IFRT and 2 relapses were observed among the 23 patients treated with the anti-CD20 MoAb (8.7%), 1 having achieved a MRD negativity and 1 not. No significant differences in event-free survival have so far been observed between the three groups. Conclusions The MRD data of this phase II trial for early stage FL indicate that RT alone is often insufficient to eradicate the disease, being capable of inducing a negative MRD only in 40% of evaluable cases, with a long-lasting effect only in half of them. The primary objective of this study - MRD negativity after immunotherapy - was achieved, obtaining the disappearance of BCL2/IGH rearranged cells in the majority of patients treated with ofatumumab. The strategy of an immunotherapy consolidation after IFRT in MRD-positive patients allowed to increase molecular responses. A longer follow-up and further studies on larger patient populations will allow to conclusively define the impact of this MRD-driven strategy also on clinical outcome. Disclosures Pulsoni: Roche: Consultancy, Speakers Bureau; Takeda: Consultancy; Pfizer: Consultancy; Sandoz: Consultancy; Gilead: Speakers Bureau; Merk: Consultancy; Bristol Meyer Squibb: Speakers Bureau. Ferrero:Servier: Speakers Bureau; EUSA Pharma: Membership on an entity's Board of Directors or advisory committees; Gilead: Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Luminari:ROCHE: Other: Role as Advisor ; CELGENE: Other: Role as Advisor & Travel Grant; TAKEDA: Other: Travel Grant; GILEAD: Other: Lecturer . Liberati:Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Clinical trial support; Celgene: Honoraria, Other: Clinical trial support; Bristol-Myers Squibb: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Janssen: Honoraria; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Clinical trial support; Roche: Other: Clinical trial support; Novartis: Other: Clinical trial support. Ferreri:Roche: Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Kite: Consultancy. Nassi:Takeda: Consultancy; Janssen: Consultancy; Merck: Consultancy. Corradini:Roche: Honoraria; Novartis: Honoraria; kite: Honoraria; KiowaKirin: Honoraria; Janssen: Honoraria; Gilead: Honoraria; Daiichi Sankyo: Honoraria; Celgene: Honoraria; Amgen: Honoraria; Abbvie: Honoraria; Servier: Honoraria; Sanofi: Honoraria; Takeda: Honoraria. Mannina:Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees. Arcaini:Celgene: Speakers Bureau; Gilead Sciences: Research Funding; Bayer, Celgene, Gilead Sciences, Roche, Sandoz, Janssen-Cilag, VERASTEM: Consultancy; Celgene, Roche, Janssen-Cilag, Gilead: Other: Travel expenses. Galimberti:Roche: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Speakers Bureau. Ladetto:AbbVie: Honoraria; Roche: Honoraria; ADC Therapeutics: Honoraria; Acerta: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; J&J: Honoraria; Celgene: Honoraria. Foà:Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. OffLabel Disclosure: The anti-CD20 MoAb Ofatumomab is employed to eradicate Minimal Residual Disease in early stage Follicular Lymphoma(FL). The drug is registered for Chronic Lymphocytic Leukemia, not for FL.
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