Thrombotic Thrombocytopenic Purpura Induced by Immune Checkpoint Inhibitiors: A Case Report and Review of the Literature

Immune checkpoint inhibitor induced nephrotoxicity: An ongoing challenge

Although immune checkpoint inhibitors (ICIs) have dramatically revolutionized the field of oncology over the last decade, severe immune-related adverse events (irAEs) are potentially life-threatening. In comparison with toxicities involving the skin, gastrointestinal tract and endocrine system, nephrotoxicity is less common but often underestimated due to difficult diagnosis. Management usually consists of treatment discontinuation and/or corticosteroid use. In this review, we summarize current knowledge of ICI-induced nephrotoxicity, evaluating drawbacks and future perspectives.

Immune-Mediated Thrombotic Thrombocytopenic Purpura Following mRNA-Based COVID-19 Vaccine BNT162b2: Case Report and Mini-Review of the Literature

Introduction

An increasing number of case reports have associated vaccinations against coronavirus disease 2019 (COVID-19) with immune-mediated thrombotic thrombocytopenic purpura (iTTP), a very rare but potentially life-threatening thrombotic microangiopathy, which leads to ischemic organ dysfunction. Thrombus formation in iTTP is related to a severe deficiency of the specific von Willebrand-factor-cleaving protease ADAMTS13 due to ADAMTS13 autoantibodies.

Methods

We present a case of iTTP following exposure to the mRNA-based COVID-19 vaccine BNT162b2 (Comirnaty^®, Pfizer-BioNTech). In addition, we review previously reported cases in the literature and assess current evidence.

Results

Apart from our case, twenty cases of iTTP occurring after COVID-19 vaccination had been published until the end of November 2021. There were 11 male and 10 female cases; their median age at diagnosis was 50 years (range 14–84 years). Five patients (24%) had a preexisting history of iTTP. Recombinant adenoviral vector-based vaccines were involved in 19%, mRNA-based vaccines in 81%. The median onset of symptoms after vaccination was 12 days (range 5–37), with 20 cases presenting within 30 days. Treatment included therapeutic plasma exchange in all patients. Additional rituximab, caplacizumab, or both these treatments were given in 43% (9/21), 14% (3/21), and 24% (5/21) of cases, respectively. One patient died, despite a prolonged clinical course in one patient, all surviving patients were in clinical remission at the end of the observational period.

Conclusion

Clinical features of iTTP following COVID-19 vaccination were in line with those of pre-pandemic iTTP. When timely initiated, an excellent response to standard treatment was seen in all cases. ADAMTS13 activity should be determined pre-vaccination in patients with a history of a previous iTTP episode. None of the reported cases met the WHO criteria for assessing an adverse event following immunization (AEFI) as a consistent causal association to immunization. Further surveillance of safety data and additional case-based assessment are needed.

Thrombotic microangiopathy (TMA) in adult patients with solid tumors: a challenging complication in the era of emerging anticancer therapies

Thrombotic microangiopathy (TMA) is a syndrome that encompasses a group of disorders defined by the presence of endothelial damage leading to abnormal activation of coagulation, microangiopathic hemolytic anemia and thrombocytopenia, occlusive (micro)vascular dysfunction, and organ damage. TMA may occur in patients with malignancy as a manifestation of cancer-related coagulopathy itself or tumor-induced TMA (Ti-TMA) as a paraneoplastic uncommon manifestation of Trousseau syndrome. TMA can also be triggered by other overlapping conditions such as infections or more frequently as an adverse effect of anticancer drugs (drug-induced TMA or Di-TMA) due to direct dose-dependent toxicity or a drug-dependent antibody reaction. The clinical spectrum of TMA may vary widely from asymptomatic abnormal laboratory tests to acute severe potentially life-threatening forms due to massive microvascular occlusion. While TMA is a rare condition, its incidence may progressively increase within the context of the great development of anticancer drugs and the emerging scenarios in supportive care in cancer. The objective of the present narrative review is to provide a general perspective of the main causes, the key work-up clues that allow clinicians to diagnose and manage TMA in patients with solid tumors who develop anemia and thrombocytopenia due to frequent overlapping causes.

The Efficacy and Safety of Plasma Exchange in the Treatment of Thrombotic Thrombocytopenic Purpura

Background

Thrombotic thrombocytopenic purpura (TTP) is a clinically rare thrombotic cardiovascular and microvascular disease. The purpose of this study was to observe the clinical efficacy and safety of plasma exchange in the treatment of TTP.

Methods

A total of 16 TTP patients who underwent plasma exchange from January 2015 to December 2020 were selected. The clinical data of all patients were collected for retrospective analysis. The effective rate of treatment, the changes of blood cell count before and after treatment, and adverse reactions during treatment were analyzed.

Results

A total of 50 plasma exchanges were performed in 16 TTP patients. After plasma exchange treatment, there were 4 invalid and 12 improved patients. The total effective rate of plasma exchange in patients with TTP was 75.0%. After treatment, platelet count (PLT) and hemoglobin (Hb) levels were significantly increased in TTP patients. Compared with before treatment, lactate dehydrogenase (LDH), indirect bilirubin (IBIL), total bilirubin (TBIL), and broken red blood cells were significantly reduced. In addition, 3 adverse reactions occurred in 50 plasmapheresis procedures, and the incidence of adverse reactions was 6.0%.

Conclusion

Plasma exchange therapy has a good therapeutic effect on TTP and can significantly improve abnormal blood cell count in patients with high safety.

The Intriguing Connections between von Willebrand Factor, ADAMTS13 and Cancer

von Willebrand factor (VWF) is a complex and large protein that is cleaved by ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13), and together they serve important roles in normal hemostasis. Malignancy can result in both a deficiency or excess of VWF, leading to aberrant hemostasis with either increased bleeding or thrombotic complications, as respectively seen with acquired von Willebrand syndrome and cancer-associated venous thromboembolism. There is emerging evidence to suggest VWF also plays a role in inflammation, angiogenesis and tumor biology, and it is likely that VWF promotes tumor metastasis. High VWF levels have been documented in a number of malignancies and in some cases correlate with more advanced disease and poor prognosis. Tumor cells can induce endothelial cells to release VWF and certain tumor cells have the capacity for de novo expression of VWF, leading to a proinflammatory microenvironment that is likely conducive to tumor progression, metastasis and micro-thrombosis. VWF can facilitate tumor cell adhesion to endothelial cells and aids with the recruitment of platelets into the tumor microenvironment, where tumor/platelet aggregates are able to form and facilitate hematogenous spread of cancer. As ADAMTS13 moderates VWF level and activity, it too is potentially involved in the pathophysiology of these events. VWF and ADAMTS13 have been explored as tumor biomarkers for the detection and prognostication of certain malignancies; however, the results are underdeveloped and so currently not utilized for clinical use. Further studies addressing the basic science mechanisms and real word epidemiology are required to better appreciate the intriguing connections between VWF, ADAMTS13 and malignancy. A better understanding of the role VWF and ADAMTS13 play in the promotion and inhibition of cancer and its metastasis will help direct further translational studies to aid with the development of novel cancer prognostic tools and treatment modalities.

A Rare Association of Thrombotic Thrombocytopenic Purpura with Systemic Lupus Erythematosus in a Sudanese Woman: Case Report

Thrombotic thrombocytopenic purpura (TTP) is an uncommon life-threatening condition characterized by hemolytic disorders. The coexistence of systemic lupus erythematosus (SLE) with TTP is extremely rare, although Africans are at increased risk due to inherited risk factors. This report describes a rare clinical manifestation of TTP associated with SLE in a Sudanese patient. A 41-year-old Sudanese woman presented to the emergency department with symptoms and features that were suggestive of malaria, for which she had been treated accordingly. However, a few days later she complained of fever, and was found to have a body temperature of 39.5°C, jaundice, anemia, and thrombocytopenia. Soon after admission, she developed confusion and unrecordable blood pressure. After the patient had stabilized, clinical assessment, immune-system investigation (antinuclear antibody profile, complements, blood panel), and imaging revealed a diagnosis of TTP associated with SLE. The patient received imipenem 500 mg, five sessions of plasmapheresis (60 mL/kg), methylprednisolone 1 g pulse for 3 days, and rituximab 375 mg/week. Three weeks later, the patient was discharged after her condition had improved, and she is now on regular follow-up.

Immune Checkpoint Inhibitor-Associated Thrombotic Thrombocytopenic Purpura in a Patient With Metastatic Non-Small-Cell Lung Cancer

Background: Immune-related adverse events (irAEs) are secondary reactions related to treatment with immune checkpoint inhibitors (ICIs). There have been six cases published reporting on an association between patients undergoing treatment with ICIs and the occurrence of acquired thrombotic thrombocytopenic purpura (TTP).

Case report: We report a 61-year-old male receiving treatment with chemoimmunotherapy followed by pembrolizumab maintenance therapy for advanced non-small-cell lung cancer, presenting with bleeding symptoms, anemia, and thrombocytopenia. The patient received pembrolizumab seven times in total, in three-week cycles. Laboratory testing demonstrated hemolytic anemia, which, in combination with other findings, suggested thrombotic microangiopathy (TMA). PLASMIC scoring and specialized testing with ADAMTS13 activity and inhibitor confirmed a diagnosis of TTP. The patient was started on therapy with plasmapheresis and glucocorticoids, resulting in clinical improvement. The patient chose to leave the hospital under the care of home hospice and died approximately one month after being discharged.

Conclusions: Of the six cases of ICI-induced TTP, only one other was treated with pembrolizumab to our knowledge to date. Our patient experienced an adverse reaction marked by thrombocytopenia and hematuria after drug exposure. With symptom improvement after ICI discontinuation and recurrence on readministration, a presumptive diagnosis of ICI-associated TTP was made. This case report and literature review emphasize the need for close observation of patients undergoing ICI therapy for potential rare irAEs. The further investigation aimed at the study of risk factors, disease severity, and treatment response to this form of secondary TTP is needed to guide treatment decisions.

Nephrotoxicity of Immune Checkpoint Inhibitors: Acute Kidney Injury and Beyond

Immune checkpoint inhibitors (ICIs) are novel humanized monoclonal antibodies that release the brakes on the immune system, resulting in the destruction of tumor cells. ICIs are approved for a variety of hematological and solid organ malignancies, and the list has been growing since the approval of ipilimumab in 2011. ICIs are associated with a variety of immune-related adverse events (irAEs). irAEs commonly affect the skin, the gastrointestinal (GI) tract, and the endocrine system. Acute kidney injury (AKI) due to ICIs (ICI-AKI) occurs in a minority of patients, and it is usually due to acute tubulointerstitial nephritis (ATIN). Treatment with corticosteroids is usually successful. There have been reports of electrolyte disorders due to ICIs, including hyponatremia, hypocalcemia, hypokalemia, and Fanconi syndrome. The diagnosis of electrolyte disorders requires vigilance and routine laboratory monitoring.