Thrombotic thrombocytopenic purpura in a patient with lenalidomide-responsive multiple myeloma

Navigating the Nexus: Lenalidomide-Associated Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic microangiopathy (TMA) marked by thrombocytopenia, microangiopathic hemolytic anemia, and microvascular thrombosis leading to end-organ damage. While TTP commonly results from hereditary or acquired ADAMTS13 deficiency, its association with lenalidomide is notably rare. The link between lenalidomide and TMA is unclear and requires more studies, given the high mortality risk associated with TTP. The underlying mechanism may involve immunomodulatory effects leading to ADAMTS13 inhibitory antibody formation. Herein, we present a case of a 56-year-old male with a history of multiple myeloma status post autologous stem cell transplant, on lenalidomide maintenance therapy for over five years, who presented with progressive weakness, jaundice, palpitations, and paraesthesia in his extremities. On arrival, the patient was afebrile and was neurologically intact except for the subjective paraesthesia. He was found to have critically low ADAMTS13 activity at <0.03 IU/mL and detectable ADAMTS13 inhibitors, with other findings of TTP, requiring discontinuation of lenalidomide, in addition to receiving treatment for this life-threatening TMA.

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.

Thrombotic Microangiopathy, an Unusual Form of Monoclonal Gammopathy of Renal Significance: Report of 3 Cases and Literature Review

Monoclonal gammopathies result from neoplastic clones of the B-cell lineage and may cause kidney disease by various mechanisms. When the underlying clone does not meet criteria for a malignancy requiring treatment, the paraprotein is called a monoclonal gammopathy of renal significance (MGRS). One rarely reported kidney lesion associated with benign paraproteins is thrombotic microangiopathy (TMA), provisionally considered as a combination signifying MGRS. Such cases may lack systemic features of TMA, such as a microangiopathic hemolytic anemia, and the disease may be kidney limited. There is no direct deposition of the paraprotein in the kidney, and the presumed mechanism is disordered complement regulation. We report three cases of kidney limited TMA associated with benign paraproteins that had no other detectable cause for the TMA, representing cases of MGRS. Two of the cases are receiving clone directed therapy, and none are receiving eculizumab. We discuss in detail the pathophysiological basis for this possible association. Our approach to therapy involves first ruling out other causes of TMA as well as an underlying B-cell malignancy that would necessitate direct treatment. Otherwise, clone directed therapy should be considered. If refractory to such therapy or the disease is severe and multisystemic, C5 inhibition (eculizumab or ravulizumab) may be indicated as well.

How I treat microangiopathic hemolytic anemia in patients with cancer

Microangiopathic hemolytic anemia (MAHA) with thrombocytopenia, suggests a thrombotic microangiopathy (TMA), linked with thrombus formation affecting small or larger vessels. In cancer patients, it may be directly related to the underlying malignancy (initial presentation or progressive disease), to its treatment, or a separate incidental diagnosis. It is vital to differentiate incidental thrombotic thrombocytopenia purpura or atypical hemolytic uremic syndrome in cancer patients presenting with a TMA, as they have different treatment strategies, and prompt initiation of treatment impacts outcome. In the oncology patient, widespread microvascular metastases or extensive bone marrow involvement can cause MAHA and thrombocytopenia. A disseminated intravascular coagulation (DIC) picture may be precipitated by sepsis or driven by the cancer itself. Cancer therapies may cause a TMA, either dose-dependent toxicity, or an idiosyncratic immune-mediated reaction due to drug-dependent antibodies. Many causes of TMA seen in the oncology patient do not respond to plasma exchange and, where feasible, treatment of the underlying malignancy is important in controlling both cancer-TMA or DIC driven disease. Drug-induced TMA should be considered and any putative causal agent stopped. We will discuss the differential diagnosis and treatment of MAHA in patients with cancer using clinical cases to highlight management principles.

Renal and pulmonary thrombotic microangiopathy triggered by proteasome-inhibitor therapy in patient with smoldering myeloma: A renal biopsy and autopsy case report

RATIONALE

Thrombotic microangiopathy (TMA) is a group of clinical syndromes characterized by excessive platelet activation and endothelial injury that leads to acute or chronic microvascular obliteration by intimal mucoid and fibrous thickening, with or without associated thrombi. It frequently involves the kidney but may involve any organ or system at variable frequencies depending on the underlying etiology. Among its numerous causes, drug toxicities and complement regulation abnormalities stand out as some of the most common. A more recently described association is with monoclonal gammopathy. Lung involvement by TMA is infrequent, but has been described in Cobalamin C deficiency and post stem-cell transplantation TMA.

PATIENT CONCERNS

This is the case of a patient with smoldering myeloma who received proteasome-inhibitor therapy due to retinopathy and developed acute renal failure within one week of therapy initiation.

DIAGNOSES

A renal biopsy showed thrombotic microangiopathy. At the time, mild pulmonary hypertension was also noted and presumed to be idiopathic.

INTERVENTIONS

Given the known association of proteasome-inhibitor therapy with thrombotic microangiopathy, Bortezomib was discontinued and dialysis was initiated.

OUTCOMES

Drug withdrawal failed to prevent disease progression and development of end-stage renal disease, as well as severe pulmonary hypertension that eventually lead to the patient's death.

LESSONS

To our knowledge, this is the first reported case of pulmonary involvement by TMA associated with monoclonal gammopathy which appears to have been triggered by proteasome-inhibitor therapy. Clinicians should be aware of this possibility to allow for more prompt recognition of pulmonary hypertension as a potential manifestation of monoclonal gammopathy-associated TMA, especially in patients also receiving proteasome-inhibitors, so that treatment aiming to slow disease progression can be instituted.

Thrombotic microangiopathy associated with monoclonal gammopathy

Thrombotic microangiopathy (TMA) is a rare disease comprising of a diverse set of disorders linked by a common histologic finding of endothelial injury. Monoclonal immunoglobulins may act as a potential trigger in the pathogenesis of TMA. To determine the prevalence of monoclonal gammopathy and clinicopathological features of TMA associated with monoclonal immunoglobulin, we performed a retrospective study in adults (18 and older) with a clinical diagnosis of TMA. Of 146 patients with TMA, we detected monoclonal immunoglobulin in 20 patients (13.7%). Among patients 50 and older, the prevalence of monoclonal gammopathy was 21%, which is approximately five-fold higher than the 4.2% expected rate in this population. Fifteen patients had monoclonal gammopathy of undetermined significance, one had multiple myeloma, one with smoldering myeloma, two had POEMS syndrome, and one had T-cell lymphocytic leukemia. Renal biopsy was performed in 15 cases, of which six showed thrombi, 11 showed mesangiolysis, and all showed double contours along glomerular capillary walls. Acute tubular injury was present in 12 cases. Treatment options were varied and included therapeutic plasma exchange in 11 patients. Ten patients progressed to end-stage renal disease, of which two received kidney transplant. Thus, our study shows an unexpectedly high prevalence of monoclonal gammopathy in patients with TMA, suggesting a potential pathogenetic mechanism. This study underscores the importance of evaluating for a monoclonal gammopathy in patients with TMA as well as the potential for targeting the underlying hematologic disorder as an approach to treating TMA.