Does Systemic Lupus Erythematosus (SLE) increase the risk of Thrombotic Thrombocytopenic Purpura (TTP)?

From the Guidelines

Systemic lupus erythematosus (SLE) is indeed associated with an increased risk of thrombotic thrombocytopenic purpura (TTP), with patients having approximately 20-40 times higher risk of developing TTP compared to the general population. This association is clinically significant because both conditions can present with overlapping features including thrombocytopenia, hemolytic anemia, and neurological symptoms, making diagnosis challenging 1. The increased risk is thought to be related to the autoimmune nature of both conditions, with SLE patients having dysregulated immune responses that can lead to ADAMTS13 autoantibody formation, the key pathophysiological mechanism in acquired TTP.

Key Considerations

• The presence of antiphospholipid antibodies in many SLE patients may contribute to microvascular thrombosis.
• Management of TTP in SLE patients typically requires prompt plasma exchange therapy, high-dose corticosteroids, and often rituximab.
• Immunosuppressive agents used for SLE management, such as cyclophosphamide or mycophenolate mofetil, may also help control the underlying autoimmune process.
• Close monitoring of ADAMTS13 activity levels and platelet counts is essential for tracking treatment response and predicting relapse risk in these patients.

Diagnosis and Treatment

• The diagnosis of TTP is mainly reserved for patients with TMA and low ADAMTS13 activity (<10%) 1.
• The treatment of confirmed TTP in LN is extrapolated from that of acquired TTP and includes plasma exchange, high-dose glucocorticoids, rituximab, and/or caplacizumab (von Willebrand factor inhibitor) 1.
• Patients with LN and suspected thrombotic microangiopathy should be managed according to the underlying etiology of TMA, as shown in Figure 13.1 1.
• Testing for ADAMTS13 activity and antibodies to ADAMTS13, as well as antiphospholipid antibodies, is crucial in diagnosing and managing TTP in SLE patients 1.

Recommendations

• Prompt plasma exchange therapy, high-dose corticosteroids, and rituximab should be considered in the management of TTP in SLE patients.
• Immunosuppressive agents, such as cyclophosphamide or mycophenolate mofetil, may also be used to control the underlying autoimmune process.
• Close monitoring of ADAMTS13 activity levels and platelet counts is essential for tracking treatment response and predicting relapse risk in these patients.

From the Research

Association between Systemic Lupus Erythematosus (SLE) and Thrombotic Thrombocytopenic Purpura (TTP)

• The association between SLE and TTP is a rare but life-threatening condition, with studies suggesting that SLE may increase the risk of developing TTP 2, 3, 4, 5, 6.
• Clinical manifestations of SLE-associated TTP include hemolytic anemia, thrombocytopenia, neurological deficits, and renal impairment 2, 3, 4, 5, 6.

Clinical Features and Prognosis

• Patients with SLE-associated TTP often have moderate to severe lupus disease activity, and testing of LDH level and blood smear should be performed when kidney and neurological symptoms arise in children with SLE 4.
• The use of combination therapy, including glucocorticoids, immunosuppressive agents, and plasma exchange, has been shown to provide satisfactory clinical outcomes in patients with SLE-associated TTP 2, 4, 5.
• Renal impairment may be a risk factor related to poor prognosis in patients with SLE-associated TTP 2.

Treatment and Management

• Plasma exchange combined with glucocorticoids is an effective treatment method for SLE-associated TTP, and the use of low-dose rituximab has been shown to be effective in refractory cases 5.
• Early diagnosis and treatment are crucial to improve prognosis, and measurement of ADAMTS13 activity and the anti-ADAMTS13 antibody titer are necessary for diagnosis and predicting prognosis and recurrence of the disease 6.