Characterization of novel mutations in the TEL-patch domain of the telomeric factor TPP1 associated with telomere biology disorders.

Telomeres are nucleoprotein structures that protect the chromosome ends from degradation and fusion. Telomerase is a ribonucleoprotein complex essential to maintain the length of telomeres. Germline defects that lead to short and/or dysfunctional telomeres cause telomere biology disorders (TBDs), a group of rare and heterogeneous Mendelian diseases including pulmonary fibrosis, dyskeratosis congenita, and Høyeraal-Hreidarsson syndrome. TPP1, a telomeric factor encoded by the gene ACD, recruits telomerase at telomere and stimulates its activity via its TEL-patch domain that directly interacts with TERT, the catalytic subunit of telomerase. TBDs due to TPP1 deficiency have been reported only in 11 individuals. We here report four unrelated individuals with a wide spectrum of TBD manifestations carrying either heterozygous or homozygous ACD variants consisting in the recurrent and previously described in-frame deletion of K170 (K170∆) and three novel missense mutations G179D, L184R, and E215V. Structural and functional analyses demonstrated that the four variants affect the TEL-patch domain of TPP1 and impair telomerase activity. In addition, we identified in the ACD gene several motifs associated with small deletion hotspots that could explain the recurrence of the K170∆ mutation. Finally, we detected in a subset of blood cells from one patient, a somatic TERT promoter-activating mutation that likely provides a selective advantage over non-modified cells, a phenomenon known as indirect somatic genetic rescue. Together, our results broaden the genetic and clinical spectrum of TPP1 deficiency and specify new residues in the TEL-patch domain that are crucial for length maintenance and stability of human telomeres in vivo.

Biclonal Gammopathies in South Tunisia: Clinical and Biological Characteristics.

OBJECTIVE: Biclonal gammopathies (BGs) are rare situations characterized by the production of 2 monoclonal proteins. There are no available data on BGs in North Africa. We aimed to estimate the prevalence of BGs in our population and describe their clinical and laboratory features. METHODS: We conducted a 31-year retrospective study including patients with persistent double monoclonal bands based on the results of immunofixation/immunoelectrophoresis. RESULTS: A total of 35 patients with available clinical data (sex ratio, M/F = 1.53; mean age, 70 ±â€…10.87 years [range, 45-90 years]) were included. The main associated conditions were multiple myeloma (MM) (40%), BG of undetermined significance (BGUS) (34%), and lymphoproliferative diseases (23%). Only one-third of the patients had 2 monoclonal spikes on serum protein electrophoresis. The most common paraprotein combinations were immunoglobulin (Ig)G-IgG (25%) and IgG-IgA (23%) with different light chains in one-half of the cases. The mean follow-up was 25.6 months (median, 12 months). No BGUS evolved into a malignant disease. CONCLUSION: BGs are rare in clinical laboratory routine but must be accurately identified by the pathologist. Our cohort is characterized by a high prevalence of BGUS compared with MM.

Non-Hodgkin's lymphoma developed during imatinib mesylate treatment of chronic myeloid leukemia.

INTRODUCTION: Non-Hodgkin lymphoma induced by imatinib, as a tyrosine kinase inhibitor, is a rare complication. CASE REPORT: A 54-year-old female with a history of chronic myeloid leukemia (CML) was treated with imatinib as first-line therapy. The patient achieved a profound molecular response with treatment-free remission after five years but lost major molecular responses. A second deep molecular remission was again achieved. Nine years after imatinib therapy, the patient developed odynophagia and rhinorrhea. Physical examination revealed enlarged tonsils with a tumor-like appearance without palpable lymph nodes. Immunohistochemical examination of the tonsils revealed a large B-cell lymphoma. According to Naranjo's algorithm, the causality relationship with the drug is possible with a score of 3. MANAGEMENT AND OUTCOME: Imatinib was discontinued. The lymphoma was treated with rituximab and chemotherapy. DISCUSSION: Non-Hodgkin's lymphoma is a rare side effect of tyrosine kinase inhibitors and highlights the importance of follow-up CML patients.

Complexity of diagnosing and treating langerhans cell sarcoma: A case report.

INTRODUCTION: Langerhans cell sarcoma (LCS) is a very rare malignant tumor of Langerhans cells that may metastasize to many organs. The diagnosis of this tumor is difficult and its prognosis is poor. AIM: To report the difficulty to diagnose LCS, and discuss therapeutic management of this rare entity. CASE PRESENTATION: We report a case of LCS in a 52-year-old man who presented with an axillar lymphadenopathy. The diagnosis of nodular sclerosis type Hodgkin's disease was established after histologic examination. The patient was treated with chemotherapy (ABVD regimen: Doxorubicin, Bleomycin, Vinblastine, Dacarbazine) and radiotherapy with a partial response. However, disease recurrence was observed and histological analysis confirmed the diagnosis of Langerhans cell sarcoma. A revision of the initial histological examination concluded to the diagnosis of sarcoma from the beginning. We chose the ESHAP (Etoposide, Methylprednisolone, Aracytine, Cisplatin) regimen and clinical improvement of LCS was obtained after 2 cycles but the patient had a fatal outcome and died by disease progression. CONCLUSION: Because of its rarity, diagnosis is difficult and an optimal treatment strategy for this disease has not yet been identified. Polychemotherapy can be an effective modality for the treatment of LCS.

Hemophilia in the south of Tunisia.

Hemophilia is a rare constitutional hemorrhagic disorder. There is insufficient epidemiological data on hemophilia in Tunisia. To describe the epidemiological, clinical, therapeutic, and outcome of a cohort of patients with hemophilia in southern Tunisia. A retrospective study was conducted on patients with hemophilia at the Hemophilia Treatment Center of Southern Tunisia in Sfax over 38 years (from January 1982 to December 2020). Data were collected in a regional hemophilia registry of the South Tunisian center. We collected 141 cases of hemophilia, 85% of whom had hemophilia A and 15% had hemophilia B. The severe form represented 65%, followed by the moderate form at 25%. The prevalence of hemophilia was 4.4 in 100 000 population. Family history of hemophilia was found in 70%. The mean age of patients at diagnosis was 28 months. Hemophilia was detected in 87% of cases after hemorrhagic syndrome. Bleeding occurred mainly in hemarthrosis (73%), hematoma (70%), and visceral bleeding (28%). Intracranial bleeding occurred in 6% of cases. Thirty-six percent of patients were on prophylactic therapy. Hemophilic arthropathy was the most important orthopedic complication in our patients (38%). Inhibitory antibodies occurred in 16% of PWH. Transfusion-transmitted infections with HIV and hepatitis C were in 2 and 31% of cases, respectively. The prevalence of hemophilia is still underestimated in our center. The severe form of hemophilia is the most frequent. Hemophilic arthropathy was the most important complication in our patients. This showed that hemophilia is still a disabling disease in our country.

Aplastic anemia secondary to tyrosine kinase inhibitor therapy in a patient with chronic myeloid leukemia.

INTRODUCTION: Nilotinib, as the second generation of tyrosine kinase inhibitor, has significant efficacy in patients with chronic myeloid leukemia resistant or intolerant to Imatinib. Aplastic anemia induced by tyrosine kinase inhibitors is an uncommon complication. CASE REPORT: A 34-year-old female case with CML in the chronic phase was treated with Imatinib in first-line therapy. Nilotinib was switched because of failure to achieve complete cytogenetic response at 6 months following Imatinib. Three years with Nilotinib, the patient developed a persistent pancytopenia grade 4 while a major molecular response was achieved. MANAGEMENT & OUTCOME: Nilotinib was discontinued. However, the hematologic finding of the patient had not recovered after three months. A bone marrow biopsy showed marked hypocellularity and fatty tissue without evidence of myelofibrosis. Immunosuppressive therapy was started. Unfortunately, the patient died due to septic and hemorrhagic shock nine months after Nilotinib interruption. According to Naranjo's algorithm, the causality relationship with the drug is probable with a score of 5. DISCUSSION: Aplastic anemia is an uncommon adverse event of tyrosine kinase inhibitors but it can be a fatal complication. The early diagnosis of aplastic anemia related to Nilotinib therapy is needed to avoid further detrimental effects of the drug.

Prospective observational study of palliative care in hematological malignancies: Report of one year of practice.

INTRODUCTION: Palliative care is an approach that improves the quality of life of patients with advanced disease. OBJECTIVE: The aim of this study is to evaluate the process of palliative care in patients with hematologic malignancies. METHODS: In this prospective observational study, we included patients with hematologic malignancies who received palliative care over a 12 month period from June 1, 2019, to May 31, 2020 at the day care hospital of the hematology department in University Hospital of Sfax, Tunisia. Blood transfusion was used to relieve symptoms of anemia and bleeding. RESULTS: Fifty-five patients were included. The median age was 68 years. Forty-three percent of patients were diagnosed with acute leukemia and 41.8% with myelodysplastic syndrome. Red cell and platelet transfusions were indicated in 94.5% and 36.3% of cases respectively. Patients reported improvement after blood transfusion in 50% of cases. Twenty-five transfusion reactions (45%) were noted. Fever was noted in 33 patients (60%), with documented sites of infection in 84.8% of them. Pulmonary infection was frequently noted (50%). Antimicrobial treatment was prescribed in all febrile cases. Pain was reported in 22 patients and in 77.5% of these cases, it was nociceptive. Patients who received analgesics showed clinical improvement in pain in 81% of cases. Anorexia with malnutrition was reported in 23% of cases which was treated with enteral nutrition in 75% of cases. Sleep disturbance (20 patients), anxiety (7 patients), and depression (4 patients) were mentioned respectively. CONCLUSION: Palliative care in hematology should be a multidisciplinary care approach with a global management of the various physical, psychological and sociological complications.

Hypersensitivity pneumonitis related to imatinib mesylate therapy in a patient with chronic myeloid leukemia.

INTRODUCTION: Pulmonary toxicity causally related to Imatinib (IM) therapy is uncommon in patients with chronic myeloid leukemia. CASE REPORT: A 61-year-old patient with chronic myeloid leukemia was treated with IM at 400 mg daily dose. One month within IM, he developed skin lesions and then acute dyspnea and non-productive cough. Chest radiograph and high-resolution lung computed tomography (CT) revealed bilateral reticulonodular infiltration in both lungs. According to Naranjo's algorithm, the causality relationship with the drug is probable with a score of 7. The pharmacovigilance investigation was carried out and implicated IMManagement & outcome: IM was discontinued and started steroid therapy (Prednisolone®) at 1 mg/kg daily. Two weeks after, the dyspnea, and abnormal X-ray and CT findings are improved. DISCUSSION: The early diagnosis of pulmonary toxicity related to IM therapy is needed to avoid further determinal effects of the drug.

Homozygous pArg610del Mutation Unusually Associated With Severe Delay of Growth in 2 Acid Sphingomyelinase Deficiency-affected Sibs.

BACKGROUND: Typically, patients with Acid Sphingomyelinase Deficiency (ASMD) because of p.Arg610del mutation, have mild phenotype with normal linear growth. OBSERVATION: We reported the case of 2 Tunisian brothers who have been referred for splenomegaly, polyadenopathies, pubertal, and growth delay. Molecular testing of SMPD1 gene revealed the presence of a homozygous p.Arg610del mutation. Lysosphingomyelin and its isoform-509 were both increased confirming ASMD for both cases. Growth hormone deficiency was highly suspected but growth hormone response after stimulating tests was acceptable for both patients. CONCLUSIONS: There is no correlation between phenotype-genotype in case of p.Arg610del mutation that could be associated to a severe delay of growth.

Adult Gaucher disease in southern Tunisia: report of three cases.

BACKGROUND: Gaucher disease (GD) is the most frequent lysosomal storage disorder; type 1 is by far the most common form. It is characterized by variability in age of onset, clinical signs and progression. It is usually diagnosed in the first or second decade of life with the appearance of bone pains, splenomegaly and thrombocytopenia, but the disease may be diagnosed at any age between 1 and 73 years. In the present study, we report 3 cases with late onset of GD in whom the disease was a surprise finding including one patient with Parkinson disease. This late onset is described as an adult form of Gaucher disease. FINDINGS: Molecular investigation showed mutational homogeneity in Tunisian adult patients suffering from GD. Indeed, all patients carry the p.N370S mutation: two patients at a homozygous state and one patient at compound heterozygous state. CONCLUSION: The p.N370S mutation presents a large variability in the onset of the disease and its clinical manifestation supporting the view that GD should be considered as a continuum phenotype rather than a predefined classification.