Primary central nervous system lymphomas in immunocompromised patients require specific response criteria.

PURPOSE: Immunosuppression is a well-established risk factor for primary central nervous system lymphomas (PCNSLs), which present in this context distinct radiological characteristics. Our aim was to describe the radiological evolution of treated PCNSL in immunocompromised patients and suggest adapted MRI response criteria. METHODS: We conducted a multicenter retrospective study of patients from the French LOC, K-Virogref and CANCERVIH network databases and enrolled adult immunocompromised patients with newly diagnosed PCNSL. RESULTS: We evaluated the baseline, intermediate, end-of-treatment and follow-up MRI data of 31 patients (9 living with HIV, 16 with solid organ transplantation and 6 with an autoimmune disease under chronic immunosuppressive therapy). At baseline, 23/30 (77%) patients had necrotic lesions with ring enhancement and 28% of the lesions were hemorrhagic. At the end of the first-line treatment, 12/28 (43%) patients could not be classified according to the IPCG criteria. Thirteen of 28 (46%) patients still harbored contrast enhancement, and 11/28 (39%) patients had persistent large necrotic lesions with a median diameter of 15 mm. These aspects were not associated with a pejorative outcome and progressively diminished during follow-up. Six patients relapsed; however, we failed to identify any neuroimaging risk factors on the end-of-treatment MRI. CONCLUSION: In immunocompromised patients, PCNSLs often harbor alarming features on end-of-treatment MRI, with persistent contrast-enhanced lesions frequently observed. However, these aspects seemed to be related to the necrotic and hemorrhagic nature of the lesions and were not predictive of a pejorative outcome. Specific response criteria for this population are thereby proposed.

Epstein-Barr Virus and immune status imprint the immunogenomics of non-Hodgkin lymphomas occurring in immune-suppressed environments.

Non-Hodgkin lymphomas (NHL) commonly occur in immune-deficient (ID) patients, both HIV-infected and transplanted, and are often EBV-driven with cerebral localization, raising the question of tumor immunogenicity, a critical issue for treatment responses. We investigated the immunogenomics of 68 lymphoproliferative disorders from 51 ID (34 posttransplant, 17 HIV+) and 17 immunocompetent patients. Overall, 72% were Large B Cells Lymphoma (LBCL) and 25% were primary central-nervous-system lymphoma (PCNSL) while 40% were EBV-positive. Tumor whole-exome and RNA sequencing, along with a bioinformatics pipeline allowed analysis of tumor mutational burden (TMB), tumor landscape and microenvironment (TME) and prediction of tumor neoepitopes. Both TMB (2.2 vs 3.4/Mb, p=0.001) and neoepitopes numbers (40 vs 200, p=0.00019) were lower in EBVpositive than in EBV-negative NHL, regardless of the immune status. In contrast both EBV and the immune status influenced the tumor mutational profile, with HNRNPF and STAT3 mutations exclusively observed in EBV-positive and ID NHL, respectively. Peripheral blood T-cell responses against tumor neoepitopes were detected in all EBV-negative cases but in only half EBV-positive ones, including responses against IgH-derived MHC-class-II restricted neoepitopes. The TME analysis showed higher CD8 T cell infiltrates in EBVpositive vs EBV-negative NHL, together with a more tolerogenic profile composed of Tregs, type-M2 macrophages and an increased expression of negative immune-regulators. Our results highlight that the immunogenomics of NHL in patients with immunodeficiency primarily relies on the tumor EBV status, while T cell recognition of tumor- and IgH-specific neoepitopes is conserved in EBV-negative patients, offering potential opportunities for future T cell-based immune therapies.

CANOMAD: a neurological monoclonal gammopathy of clinical significance that benefits from B-cell-targeted therapies.

CANOMAD (chronic ataxic neuropathy, ophthalmoplegia, immunoglobulin M [IgM] paraprotein, cold agglutinins, and disialosyl antibodies) is a rare syndrome characterized by chronic neuropathy with sensory ataxia, ocular, and/or bulbar motor weakness in the presence of a monoclonal IgM reacting against gangliosides containing disialosyl epitopes. Data regarding associated hematologic malignancies and effective therapies in CANOMAD are scarce. We conducted a French multicenter retrospective study that included 45 patients with serum IgM antibodies reacting against disialosyl epitopes in the context of evocating neurologic symptoms. The main clinical features were sensitive symptoms (ataxia, paresthesia, hypoesthesia; n = 45, 100%), motor weakness (n = 18, 40%), ophthalmoplegia (n = 20, 45%), and bulbar symptoms (n = 6, 13%). Forty-five percent of the cohort had moderate to severe disability (modified Rankin score, 3-5). Cold agglutinins were identified in 15 (34%) patients. Electrophysiologic studies showed a demyelinating or axonal pattern in, respectively, 60% and 27% of cases. All patients had serum monoclonal IgM gammopathy (median, 2.6 g/L; range, 0.1-40 g/L). Overt hematologic malignancies were diagnosed in 16 patients (36%), with the most frequent being Waldenström macroglobulinemia (n = 9, 20%). Forty-one patients (91%) required treatment of CANOMAD. Intravenous immunoglobulins (IVIg) and rituximab-based regimens were the most effective therapies with, respectively, 53% and 52% of partial or better clinical responses. Corticosteroids and immunosuppressive drugs were largely ineffective. Although more studies are warranted to better define the optimal therapeutic sequence, IVIg should be proposed as the standard of care for first-line treatment and rituximab-based regimens for second-line treatment. These compiled data argue for CANOMAD to be included in neurologic monoclonal gammopathy of clinical significance.

Composite and sequential lymphoma between classical Hodgkin lymphoma and primary mediastinal lymphoma/diffuse large B-cell lymphoma, a clinico-pathological series of 25 cases.

Composite and sequential lymphomas involving both classical Hodgkin lymphoma (CHL) and primary mediastinal B-cell lymphoma (PMBCL) are rare phenomena. Beyond the relevant biological interest raised by these cases, treatments and outcome data are poorly covered in the recent literature. This retrospective analysis describes the pathological and clinical characteristics of 10 composite and 15 sequential cases included after a central pathological review. At diagnosis, 70% of the composite lymphomas presented a disseminated and extranodal disease. Among the 15 sequential lymphomas, 12 were CHL at first occurrence and three were PMBCL. Based on their clinical evolution, these sequential lymphomas could be divided into early (i.e., diagnosis of second lymphoma within a year) and late [(i.e., a second lymphoma occurrence occurring after a long period of complete remission]). All composite cases were alive in complete remission after a median follow-up of 34 months. If the early sequential lymphoma presented a particularly poor outcome with a median overall survival shorter than one year, the late cases were efficiently salvaged. Further molecular studies are needed to describe the underlying biology of these rare diseases, possibly representing the extreme of tumour cell plasticity found in grey-zone lymphoma.

Iron deficiency, an unusual cause of thrombocytopenia: results from a multicenter retrospective case-controlled study.

Iron deficiency anemia (IDA) is often associated with mild to moderate thrombocytosis, and iron deficiency-associated thrombocytopenia (IDAT) is much more uncommon and often misdiagnosed as immune thrombocytopenia (ITP). To better describe the features of IDAT, we conducted a retrospective multicenter case-control study. We identified 10 patients (9 women) with a definite diagnosis IDAT, with a median age of 43.5 [range, 16-72] years and a median platelet count of 30.5 × 109/L [range, 21-80], and 7 patients with a possible diagnosis of IDAT. Bleeding manifestations were absent in all patients but one. All the patients recovered (platelet count ≥ 150 × 109/L) upon iron therapy ± red blood cell transfusion after a median time of 6 [4-39] days. When compared with 30 randomly newly diagnosed ITP patients matched on age, the baseline platelet count was significantly lower in ITP (median = 7 × 109/L [4-59], p < 0.001) whereas MPV was higher (10.5 fL [9,4-13,8] vs 8.2 fL, for IDAT p < 0.001). The median platelet count on day 7 was 337 × 109/L [113-1000] for IDAT cases vs 72 × 109/L [13-212] for ITP controls (p < 0.001). IDAT is potentially an under-recognized cause of thrombocytopenia that may be easily managed with iron therapy.

A yeast-based assay identifies drugs that interfere with immune evasion of the Epstein-Barr virus.

Epstein-Barr virus (EBV) is tightly associated with certain human cancers, but there is as yet no specific treatment against EBV-related diseases. The EBV-encoded EBNA1 protein is essential to maintain viral episomes and for viral persistence. As such, EBNA1 is expressed in all EBV-infected cells, and is highly antigenic. All infected individuals, including individuals with cancer, have CD8(+) T cells directed towards EBNA1 epitopes, yet the immune system fails to detect and destroy cells harboring the virus. EBV immune evasion depends on the capacity of the Gly-Ala repeat (GAr) domain of EBNA1 to inhibit the translation of its own mRNA in cis, thereby limiting the production of EBNA1-derived antigenic peptides presented by the major histocompatibility complex (MHC) class I pathway. Here we establish a yeast-based assay for monitoring GAr-dependent inhibition of translation. Using this assay we identify doxorubicin (DXR) as a compound that specifically interferes with the GAr effect on translation in yeast. DXR targets the topoisomerase-II-DNA complexes and thereby causes genomic damage. We show, however, that the genotoxic effect of DXR and various analogs thereof is uncoupled from the effect on GAr-mediated translation control. This is further supported by the observation that etoposide and teniposide, representing another class of topoisomerase-II-DNA targeting drugs, have no effect on GAr-mediated translation control. DXR and active analogs stimulate, in a GAr-dependent manner, EBNA1 expression in mammalian cells and overcome GAr-dependent restriction of MHC class I antigen presentation. These results validate our approach as an effective high-throughput screening assay to identify drugs that interfere with EBV immune evasion and, thus, constitute candidates for treating EBV-related diseases, in particular EBV-associated cancers.

A yeast-based assay identifies drugs active against human mitochondrial disorders.

Due to the lack of relevant animal models, development of effective treatments for human mitochondrial diseases has been limited. Here we establish a rapid, yeast-based assay to screen for drugs active against human inherited mitochondrial diseases affecting ATP synthase, in particular NARP (neuropathy, ataxia, and retinitis pigmentosa) syndrome. This method is based on the conservation of mitochondrial function from yeast to human, on the unique ability of yeast to survive without production of ATP by oxidative phosphorylation, and on the amenability of the yeast mitochondrial genome to site-directed mutagenesis. Our method identifies chlorhexidine by screening a chemical library and oleate through a candidate approach. We show that these molecules rescue a number of phenotypes resulting from mutations affecting ATP synthase in yeast. These compounds are also active on human cybrid cells derived from NARP patients. These results validate our method as an effective high-throughput screening approach to identify drugs active in the treatment of human ATP synthase disorders and suggest that this type of method could be applied to other mitochondrial diseases.

Polyunsaturated fatty acids inhibit PI3K activity in a yeast-based model system.

The phosphatidylinositol 3-kinase (PI3K) pathway controls the regulation of cell growth, proliferation, migration and apoptosis. In many tumors, the PI3K gene is mutated or overexpressed, and/or the PI3K pathway is hyperactive. PI3K is therefore a potential pharmacological target for the development of anti-tumor drugs. Some polyunsaturated fatty acids (PUFA), when given in the diet, may lead to a decrease in PI3K activity. We used a yeast-based model to reconstitute the PI3K/PTEN/Akt pathway to study the effects of long-chain polyunsaturated n-3 fatty acids on PI3K, and found that various PUFA were able to alleviate toxicity induced by overexpression of PI3K. The various PUFA had no significant effect on the steady-state level of PI3K catalytic subunit proteins (p110alpha) in yeast. However, depletion of phosphatidylinositol 4,5-bisphosphate due to overexpression of the p110alpha subunit was significantly reduced by treating the yeast cells with the various PUFA. The inhibition of mammalian PI3K, expressed in an exogenous cellular context in yeast, is likely to be a direct effect of these PUFA on PI3K rather than on other mammalian endogenous or environmental factors. These results are particularly promising given the abundance of active PUFA in marine foodstuffs and especially fish oils.