Idh1 mutations contribute to the development of T-cell malignancies in genetically engineered mice

Gain-of-function mutations in isocitrate dehydrogenase 1 (IDH1) are key drivers of hematopoietic malignancies. Although these mutations are most commonly associated with myeloid diseases, they also occur in malignancies of the T-cell lineage. To investigate their role in these diseases and provide tractable disease models for further investigation, we analyzed the T-cell compartment in a conditional knock-in (KI) mouse model of mutant Idh1. We observed the development of a spontaneous T-cell acute lymphoblastic leukemia (T-ALL) in these animals. The disease was transplantable and maintained expression of mutant IDH1. Whole-exome sequencing revealed the presence of a spontaneous activating mutation in Notch1, one of the most common mutations in human T-ALL, suggesting Idh1 mutations may have the capacity to cooperate with Notch1 to drive T-ALL. To further investigate the Idh1 mutation as an oncogenic driver in the T-cell lineage, we crossed Idh1-KI mice with conditional Trp53 null mice, a well-characterized model of T-cell malignancy, and found that T-cell lymphomagenesis was accelerated in mice bearing both mutations. Because both IDH1 and p53 are known to affect cellular metabolism, we compared the requirements for glucose and glutamine in cells derived from these tumors and found that cells bearing the Idh1 mutation have an increased dependence on both glucose and glutamine. These data suggest that mutant IDH1 contributes to malignancy in the T-cell lineage and may alter the metabolic profile of malignant T cells.Somatic mutations in isocitrate dehydrogenase 1 (IDH1) are frequently observed in a number of malignancies, including glioma, cholangiocarcinoma, chondrosarcoma, and several hematological malignancies (1). IDH1 is a cytoplasmic enzyme that catalyzes the NADP-dependent conversion of isocitrate to α-ketoglutarate (αKG). Mutations in IDH1 at arginine 132 (R132) cause an enzymatic gain of function that results in the NADPH-dependent conversion of αKG to d-2-hydroxyglutarate (2HG) (2). This metabolite is normally maintained at very low levels in cells and tissues and is not part of any known productive metabolic pathway. However, in cells and tissues of patients with IDH1 mutant tumors, 2HG builds up to high levels and is thought to contribute to tumorigenesis by inhibiting a class of αKG-dependent enzymes (1). The precise effects important for driving tumorigenesis downstream of IDH1 mutations are not fully understood and may differ between disease states.In the hematopoietic system, IDH1 mutations are most often associated with myeloid diseases, where they are commonly found in myelodysplastic syndrome and acute myeloid leukemia (3). However, IDH1 mutations are also found in a small proportion of adult T-cell acute lymphoblastic leukemia (T-ALL) (4, 5). T-ALL is an aggressive malignancy of developing T cells and is responsible for ∼25% of adult ALL (6, 7). T-ALL is thought to arise via a multistep process of oncogenic mutation that leads to the transformation of immature T cells. The genetic landscape of the disease has been characterized, and a large number of driver mutations have been identified (6). The most common genetic feature of T-ALL is the presence of activating mutations in Notch1, which are present in more than 50% of patients (8). Interestingly, IDH1 mutations seem to be confined to a subset of adult patients with T-ALL bearing an immature T-cell gene expression signature and harboring other oncogenic mutations in genes more commonly associated with myeloid malignancy, including Flt3 and DNMT3A (4, 9). This subset of T-ALL has recently been recognized as a distinct disease entity called early T-cell precursor T-ALL and is associated with therapy resistance and a particularly poor outcome (10). The role of IDH1 mutations in this subset of T-ALL is not understood.Using a myeloid lineage-specific conditional Idh1-R132-KI mouse model, we previously showed that mutant IDH1 partially blocks differentiation and produces a hematopoietic phenotype similar to human myelodysplastic syndrome (11). In this study, we crossed the Idh1-R132-KI mouse with Vav-cre animals to introduce the IDH1 R132 mutation into the entire hematopoietic system to investigate the role of Idh1 mutations in T-cell malignancy.     

Correlation of Molecular Markers in High Grade Gliomas with Response to Chemo-Radiation

Background: The standard of care in high grade glioma (HGG) is maximal safe surgical resection followed by adjuvant radiotherapy (RT) with/without chemotherapy. For anaplastic gliomas, studies have shown use of procarbazine, lomustine, vincristine (PCV) improves overall survival (OS) and progression free survival (PFS). Currently, there is substantial evidence that molecular markers strongly predict prognosis and response to treatment. Methods: Between January 2016 to January 2018, 42 patients were accrued and followed up till April 2019. The primary end points were to correlate molecular markers with response to therapy in terms of OS and PFS in HGG. The secondary end point was to evaluate frequency of 1p/19q codeletion, IDH 1 mutation, ATRX deletion and p53 in HGG patients. Results: The median age was 46 years (range 18-67) with M:F ratio 30:12. The frequency of IDH1 mutation,1p/19q codeletion, p53 mutation and ATRX mutation were 42.8%, 16.6%, 42.8% and 14.2% respectively. All the seven patients with 1p/19q codeletion had IDH1 mutation. Median follow up was 22 months. The 20-months PFS for different mutations were as follows; IDH1-mutated vs wild type: 53.6% vs 29.8%; p-0.035, 1p/19q codeleted vs non-codeleted: 85.7% vs 62.3%; p-0.011, p53 wild type vs mutated 32.1% vs 35.6%; p-0.035 and ATRX lost vs retained: 55.6% vs 53.3%; p- 0.369. The 20-months OS for IDH1 mutated vs wild type: 82.4% vs 30.6%; p-0.014, 1p/19q codeleted vs non-codeleted: 85.7% vs 65.8%; p-0.104, p53 wild-type vs mutated 45.5% vs 73.9%; p-0.036 and ATRX lost vs retained: 100% vs 60.3%; p-0.087. Conclusion: Codeletion of 1p/19q with IDH1 mutation in HGG is associated with a significantly favourable PFS. However, larger studies with longer follow up are required to evaluate OS and PFS in all the molecular subgroups.     

Lipid peroxidation in different tissues: effect of high cholesterol and fish oil in the diet

Malonyldialdehyde was measured in erythrocytes, aorta and spleen on feeding mice with high cholesterol diet in presence and absence of fish oil. Mice were grouped as: Group I: Control laboratory diet Group II: 0.16% cholesterol (sunflower oil) Group III: 1.16% cholesterol (sunflower oil) Group IV: 1.16% cholesterol (fish oil) After 7 weeks on their respective diets, erythrocytic, and splenic MDA levels were significantly higher in group III compared to controls. Also, MDA levels in aorta and spleen showed a significant increase in group IV males compared to group III males. However in group IV the erythrocyte MDA levels were almost equal to that in controls. This suggests that high cholesterol diet increases lipid peroxidation in erythrocytes, spleen and aorta. Addition of fish oil in the diet further increases lipid peroxidation in aorta and spleen, but not in the erythrocytes.     

Evaluation of downstaging in the detection of cervical neoplasia in Kolkata,India

Unaided visual inspection or "downstaging" has been suggested as a potential alternative method for cervical cancer screening in developing countries. Our study was designed to evaluate the accuracy of downstaging to detect cervical neoplasia in a low-resource setting. A total of 6,399 women aged 30-64 years were screened with downstaging by trained nonmedical health workers. Two thresholds were used to define positive downstaging: "low threshold" when any visible abnormality on the cervix was considered positive and "high threshold" when selected abnormalities such as bleeding on touch, bleeding erosion, hypertrophied oedematous cervix, congested stippled cervix and growth or ulcer constituted the positive test. All women underwent a colposcopy examination. Biopsies were directed when colposcopy revealed abnormal lesions. True disease status was defined as histologically proven moderate dysplasia and worse lesions. Since all the participants received a diagnostic (reference) investigation (biopsy and/or colposcopy), sensitivity, specificity and predictive values were estimated directly. Low- and high-threshold downstaging were positive in 1,585 (24.8%) and 460 (7.2%) women, respectively. The sensitivities of low- and high-threshold downstaging to detect high-grade precursors and invasive cancers were 48.9% and 31.9%, respectively. The specificities were 75.8% and 93.3%, respectively. These results indicate that downstaging is not suitable as an independent primary screening modality for cervical neoplasia.     

Passive active prophylaxis against Hepatitis B in children with acute lymphoblastic leukemia

The aim of this study was to assess the antibody response to combined passive active immunisation versus active immunisation along with interferon against Hepatitis B in 60 patients with acute lymphoblastic leukemia (ALL) between 1 and 21 years of age with negative Hepatitis B virus (HBV) serology at presentation. Thirty-one patients received combined passive active immunisation with human specific Hepatitis B immunoglobulin (HEPABIG-VHB Pharmaceuticals) and Hepatitis B vaccine (arm I) and 29 patients received active immunisation along with interferon (arm II). Protective antibody levels were detected in 89.6 and 21% patients, respectively, at the 6-month evaluation. Infection with HBV occurred in 17 and 59% patients, respectively, at the 6-month evaluation. Interferon, thus, failed to serve the role as a vaccine adjuvant. At the 9-month evaluation of patients who received immunoglobulin, protective antibody titers were lost in 8 out of 19 evaluable patients (42%) and of these, 3 patients became HBsAg reactive at this point of time. This study indicated that 47.3% patients undergoing aggressive chemotherapy responded to combined passive active prophylaxis with protective titers of antiHBs at the 9-month evaluation. However, the rate of HBV infection was greatly reduced to 27%. We suggest that usage of passive immunisation in the aggressive phase, followed by active immunisation after cessation of intense chemotherapy would be a better option to increase the rates of protective antibody levels in these immunocompromised patients with leukemia.     

Kala-azar-new developments in diagnosis and treatment

Kala-azar is an endemic, disease in many parts of India. Traditionally diagnosis of this disease was based on demonstrating the parasites in various tissues like bone marrow or splenic aspirates. However, lack of high sensitivity of these methods led to the use of various immunodiagnostic methods in the diagnosis of kala-azar. Antigen detection and polymerase chain reaction to detect parasitic DNA have been found to be useful in patients with an underlying immunosuppressive disease like AIDS. For treating kala-azar, pentavalent antimonial compounds are still the first-line agents. However, due to increasing resistance to this agent, many patients at present requie other drugs including amphotericin B and pentamidine. Toxic effects of these second-line agents have led to development of drug dellvery systems like liposomal amphotericin B, which has shown uniform efficacy in clinical trials. Combining stibogluconate with either paromomycin or interferon-γ has also been shown to be useful in many patients with drug-resistant kala-azar.     

Quality of Life in Indian Patients with Rheumatoid Arthritis

Purpose of Study: Rheumatoid arthritis (RA) is a multisystem disease with various extra-articular manifestations (EAMs). Health-related quality of life (HRQOL) issues are assuming increasing importance in chronic rheumatic diseases like RA. No data on QOL in RA is available from the Indian subcontinent. There is also a paucity of literature on the impact of EAMs on HRQOL in RA. The objective of this study was to address these lacunae. Methods: The study group comprised 81 patients with RA from a rheumatology clinic in India. Quality of life was estimated by the generic HRQOL measure: World Health Organization quality of life instrument (WHOQOL-Bref). Disease activity in RA was measured by calculating Disease Activity Score-28 (DAS28). Results: The mean HRQOL scores of the patients were 12.0±2.8, 13.2±2.7, 14.4±2.9 and 13.3±2.6 in the physical, psychological, social, and environmental domains of the WHOQOL-Bref respectively. Age, gender, disease duration, educational status, constitutional symptoms, rheumatoid factor positivity, erosions and deformities did not influence HRQOL. Disease activity had a negative influence on the physical and psychological domains. Patients with EAMs had significantly higher DAS28 scores compared to patients without EAMs. Even after adjustment for disease activity, patients with EAMs had lower HRQOL scores than patients without these features (statistically significant for physical domain). Conclusions: The physical domain of HRQOL is most affected in Indian patients with RA. Increasing disease activity and presence of EAMs worsens the quality of life.Address for correspondence: Rohini Handa, Department of Medicine, All India Institute of Medical Sciences, Ansari Nagar 110029, New Delhi, India Phone:     

Nephrogenic diabetes insipidus presenting with developmental delay and intracranial calcification

A one-year-boy presented with constipation, fever, failure to thrive and developmental delay from the neonatal period. Investigations revealed persistent hypernatremia and deranged renal functions. Diagnostic work-up was suggestive of nephrogenic diabetes insipidus (NDI). Computerized tomography of head revealed calcification in the frontal, thalamic and basal ganglia region. The rare association of NDI and intracranial calcification is discussed