Understanding Immune Thrombocytopenia: Looking Out of the Box

Cerebral venous sinus thrombosis in patient of immune thrombocytopenic purpura managed with mechanical thrombectomy: An anecdotal endovascular experience from lower middle income country

Cerebral venous sinus thrombosis in itself is rarely encountered clinical entity and its association with immune thrombocytopenic purpura (ITP) makes it more unusual presentation. No any as such standard guidelines exist that guides the prompt evidence based management in such concurrent cases but neuroendovascular modality can play a pivotal role.

Rituximab alleviates pediatric systemic lupus erythematosus associated refractory immune thrombocytopenia: a case-based review

A complication of pediatric systemic lupus erythematosus (pSLE) is immune thrombocytopenia (ITP). Although corticosteroids and immunoglobulins are frequently used as preliminary treatments, some patients do not respond to them. Rituximab has been reported to be safe and effective in the treatment of pSLE complicated with refractory ITP. Research is currently underway to determine the optimal rituximab dose for these individuals. We report a case of a child with SLE-associated ITP (SLE-ITP) who was successfully treated with rituximab. Rituximab is likely the most viable therapeutic option for refractory SLE-ITP. Furthermore, a comprehensive review of the relevant literature was performed and a concise overview of the pathogenesis and available treatment modalities for pediatric patients diagnosed with SLE and concurrent ITP was provided.

The role of BAFF and BAFF-R inhibitors in the treatment of immune thrombocytopenia; a focused review

Immune thrombocytopenia (ITP) is an autoimmune-driven disease characterized by increased destruction and impaired platelet production resulting in an enhanced risk of bleeding. Immunosuppressant agents are the most common treatment strategies for ITP. Despite their efficacy, these medications often cause unpredictable side effects. Recent investigations revealed that patients with ITP exhibit elevated B-cell activating factor (BAFF) levels in both their spleens and serum. Belimumab, a BAFF inhibitor, illustrated a promising therapeutic avenue for managing ITP by interfering with BAFF activity and long-lived plasma cell production. Both clinical and experimental studies have yielded positive outcomes when combining rituximab with an anti-BAFF monoclonal antibody in treating ITP. In addition, ianalumab, a monoclonal antibody with a dual mechanism that targets BAFF-R and deletes peripheral BAFF-R+ B cells, is currently being used for ITP treatment [NCT05885555]. The upcoming results from novel BAFF inhibitors, such as ianalumab, could offer clinicians an additional therapeutic option for treating ITP.

The many facets of immune-mediated thrombocytopenia: Principles of immunobiology and immunotherapy

Immune thrombocytopenia (ITP) is a rare autoimmune condition, due to peripheral platelet destruction through antibody-dependent cellular phagocytosis, complement-dependent cytotoxicity, cytotoxic T lymphocyte-mediated cytotoxicity, and megakaryopoiesis alteration. This condition may be idiopathic or triggered by drugs, vaccines, infections, cancers, autoimmune disorders and systemic diseases. Recent advances in our understanding of ITP immunobiology support the idea that other forms of thrombocytopenia, for instance, occurring after immunotherapy or cellular therapies, may share a common pathophysiology with possible therapeutic implications. If a decent pipeline of old and new agents is currently deployed for classical ITP, in other more complex immune-mediated thrombocytopenic disorders, clinical management is less harmonized and would deserve further prospective investigations. Here, we seek to provide a fresh overview of pathophysiology and current therapeutical algorithms for adult patients affected by this disorder with specific insights into poorly codified scenarios, including refractory ITP and post-immunotherapy/cellular therapy immune-mediated thrombocytopenia.

Simultaneous hypersensitivity reactions to trimethoprim-sulfamethoxazole and amoxicillin-clavulanate in a dog

Antibiotics are known to be able to cause hypersensitivity reactions through various mechanisms. We present a case of drug-induced immune thrombocytopenia (DITP) and anaphylactic shock occurring simultaneously in a dog after the administration of two classes of antibiotics, namely trimethoprim-sulfamethoxazole (TMP-SMX) and amoxicillin-clavulanate (AMC). The patient recovered completely from DITP on discontinuation of TMP-SMX and the anaphylactic shock caused by AMC was treated with intensive care. DITP is a rare adverse drug reaction (ADR), and anaphylactic shock is a life-threatening ADR. This is the first case report of a dog manifesting two types of hypersensitivity reactions caused by two antibiotics.

Evans syndrome caused by a deleterious mutation affecting the adaptor protein SASH3

Increasing evidence suggests multilineage cytopenias (also known as Evans syndrome) may be caused by inborn errors of immunity (IEI) with immune dysregulation. We studied a patient with autoimmune haemolytic anaemia and immune thrombocytopenia and identified a germline mutation in SASH3 (c.862C>T;p.Arg288Ter), indicating a recently identified IEI. Immunohistochemistry performed after clinically indicated splenectomy revealed severe hypoplasia/absence of germinal centres. The autoimmune phenotype was associated with an increased CD21low T-bet+ CD11c+ subset along with decreased regulatory T cells, impaired T-cell proliferation and T-cell exhaustion. The younger brother carries the same SASH3 mutation and shares immunophenotypic features but is currently clinical asymptomatic, indicating heterogeneity of SASH3 deficiency.

Immunomodulation with romiplostim as a second-line strategy in primary immune thrombocytopenia: The iROM study

Thrombopoietin receptor agonists (TPO-RAs) stimulate platelet production, which might restore immunological tolerance in primary immune thrombocytopenia (ITP). The iROM study investigated romiplostim's immunomodulatory effects. Thirteen patients (median age, 31 years) who previously received first-line treatment received romiplostim for 22 weeks, followed by monitoring until week 52. In addition to immunological data, secondary end-points included the sustained remission off-treatment (SROT) rate at 1 year, romiplostim dose, platelet count and bleedings. Scheduled discontinuation of romiplostim and SROT were achieved in six patients with newly diagnosed ITP, whereas the remaining seven patients relapsed. Romiplostim dose titration was lower and platelet count response was stronger in patients with SROT than in relapsed patients. In all patients, regulatory T lymphocyte (Treg) counts increased until study completion and the counts were higher in patients with SROT. Interleukin (IL)-4, IL-9 and IL-17F levels decreased significantly in all patients. FOXP3 (Treg), GATA3 (Th2) mRNA expression and transforming growth factor-β levels increased in patients with SROT. Treatment with romiplostim modulates the immune system and possibly influences ITP prognosis. A rapid increase in platelet counts is likely important for inducing immune tolerance. Better outcomes might be achieved at an early stage of autoimmunity, but clinical studies are needed for confirmation.

SOCS1 Haploinsufficiency Presenting as Severe Enthesitis, Bone Marrow Hypocellularity, and Refractory Thrombocytopenia in a Pediatric Patient with Subsequent Response to JAK Inhibition

Haploinsufficiency of suppressor of cytokine signaling 1 (SOCS1) is a recently discovered autoinflammatory disorder with significant rheumatologic, immunologic, and hematologic manifestations. Here we report a case of SOCS1 haploinsufficiency in a 5-year-old child with profound arthralgias and immune-mediated thrombocytopenia unmasked by SARS-CoV-2 infection. Her clinical manifestations were accompanied by excessive B cell activity, eosinophilia, and elevated IgE levels. Uniquely, this is the first report of SOCS1 haploinsufficiency in the setting of a chromosomal deletion resulting in complete loss of a single SOCS1 gene with additional clinical findings of bone marrow hypocellularity and radiologic evidence of severe enthesitis. Immunologic profiling showed a prominent interferon signature in the patient's peripheral blood mononuclear cells, which were also hypersensitive to stimulation by type I and type II interferons. The patient showed excellent clinical and functional laboratory response to tofacitinib, a Janus kinase inhibitor that disrupts interferon signaling. Our case highlights the need to utilize a multidisciplinary diagnostic approach and consider a comprehensive genetic evaluation for inborn errors of immunity in patients with an atypical immune-mediated thrombocytopenia phenotype.

Frequency and utility of bone marrow examination in relapsed/refractory immune thrombocytopenia

BACKGROUND

The diagnosis of immune thrombocytopenia (ITP) is one of exclusion. Although guidelines recommend against routine bone marrow examination (BME) at time of ITP diagnosis, the role of BME in relapsed/refractory ITP is unclear.

OBJECTIVES

To examine the frequency and predictors of BME in relapsed/refractory ITP.

PATIENTS/METHODS

This multicenter retrospective cohort study included adults with ITP who received second-line therapy in Alberta, Canada from 2012 to 2019. We calculated the frequency of BME and rate of abnormal marrow findings. Logistic regression was performed to assess predictors of BME and predictors of bone marrow pathology.

RESULTS

Of 324 patients with presumed ITP, 181 (56%) underwent BME. We observed a marked decline in the rates of BME among patients >60 years over the past decade, but not in patients younger than age 60 years. On multivariable logistic regression, older age (adjusted OR [aOR] 1.03, p = .0001), anemia (aOR 2.5, p = .01), splenomegaly (aOR 3.2, p = .01), splenectomy (aOR 2.4, p = .02), and lack of splenectomy response (aOR 3.4, p = .04) were significant predictors of BME. Abnormal marrow findings were found in eight (2% of overall cohort; 4% of BME): four myelodysplastic syndrome, one aplastic anemia, one chronic lymphocytic leukemia, one metastatic cancer, and one megaloblastic anemia. Seven (88%) underwent BME for bicytopenias/pancytopenias. Macrocytosis (aOR 9.6, p = .03) and rural residence (aOR 6.7, p = .02) were independent predictors of abnormal bone marrow findings.

CONCLUSIONS

Although routine BME is frequently performed in relapsed/refractory ITP, abnormal findings are rare. Future prospective studies are needed to help identify a subgroup of relapsed/refractory ITP who may benefit from BME.

Cerebral venous sinus thrombosis in immune thrombocytopenia patients treated with thrombopoietin receptor agonist: Case reports and literature review

Introduction and importance

Cerebral venous sinus thrombosis is an uncommon adverse event in immune thrombocytopenia (ITP) patients treated with thrombopoietin receptor agonists (TPO-RAs).

Case presentation

We reported two cases of cerebral venous sinus thrombosis after eltrombopag administration. The first case is a 29-year-old ITP woman who recently initiated eltrombopag one month before admission. She presented with progressive headache, visual disturbance, and nausea for six days with unremarkable physical examination except for bilateral optic disc edema. She was treated with enoxaparin and switched to edoxaban when discharged. The second case is a 75-year-old man with a history of vaccine-induced ITP. He was initially treated with dexamethasone and eltrombopag. One month later, he developed acute cerebral venous thrombosis with hemorrhagic infarction in the bilateral frontal lobes. Even though he was treated with intravenous heparin, his status was not improved. He received the best supportive care.

Discussion

The pathophysiology of TPO-RAs-associated cerebral venous sinus thrombosis remained unclear but might associate with platelet activation. Most cases of cerebral venous sinus thrombosis occur within two months, thus closed platelet monitoring is important.

Conclusion

Careful use and closed monitoring might prevent this event. Indications of initiation and tapering must be considered before TPO-RAs administration. Off-label use may enhance TPO-RA side effects.

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The rate of TPO-RA-associated CVT is increasing after the widespread use of TPO-RAs.

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Abnormal platelet activation may be the crucial factor for TPO-RA-associated CVT.

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Most cases of CVT occur within two months, thus closed monitoring is important.

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Before giving TPO-RAs, consider initiation and tapering indications.

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Off-label usage may unnecessarily increase the incidence of TPO-RAs adverse events.