A 35-year-old woman with influenza A-associated thrombotic thrombocytopenic purpura

Influenza-associated thrombotic thrombocytopenic purpura: A report of two cases and a brief review of the literature

BACKGROUND AND OBJECTIVES

Thrombotic thrombocytopenic purpura (TTP) is often preceded by a recent history of an acute infection and influenza is the most implicated virus.

MATERIALS AND METHODS

We identified two cases of TTP, which were preceded by influenza between 2010 and 2021. In one patient, we epitope mapped the binding specificity of antibodies using an overlapping peptide approach of the stalk protein of Influenza B and the cysteine-rich spacer domain (CRSD) of ADAMTS13. A literature search was performed for reports of influenza-associated TTP over the period 1980-2021.

RESULTS

Two patients were identified in which TTP was preceded by influenza, one Influenza A and the other Influenza B. Epitope mapping of the latter's plasma identified target epitopes in both the stalk protein of Influenza B and CRSD of ADAMTS13. The literature review revealed only seven case reports, all but one from Europe or Asia and associated with Influenza A. Severe ADAMTS13 deficiency was demonstrated in only four cases.

CONCLUSION

We report the first small case series of influenza-associated TTP. Moreover, it is the first case implicating Influenza B and a mechanism favouring polyclonal B-cell proliferation rather than molecular mimicry as the stimulus to form anti-ADAMTS13 auto-antibodies is suggested.

Sjögren's Syndrome Associated With Thrombotic Thrombocytopenic Purpura: A Case-Based Review

OBJECTIVE

To review all published cases of the rare association between thrombotic thrombocytopenic purpura (TTP) and Sjögren's syndrome (SS). The authors report an additional case of this unique association.

METHODS

Systematic review of the literature and a case report. The database were articles published in PubMed/MEDLINE, Web of Science, LILACS, and SciELO, registered from 1966 to August 2020. The DESH terms were "Sjögren's syndrome" and "thrombotic thrombocytopenic purpura," without language limitation.

RESULTS

Most patients were female (88%), and the age varied from 30 to 75 years old. Concerning the sequence of disease appearance, SS followed by TTP was seen in seven articles, TTP and SS in three, and simultaneous appearance of both diseases in three studies. Primary SS was observed in 16 patients, and secondary SS was detected in two cases: dermatomyositis and rheumatoid arthritis. Anemia was the most common TTP manifestation, followed by thrombocytopenia, fever, consciousness alteration, renal impairment, and schistocytes' appearance on a blood smear. Treatment involved plasmapheresis, plasma exchange, rituximab, glucocorticoid, and cyclophosphamide. A good outcome was noted in most studies; few patients died.

CONCLUSIONS

TTP is a rare manifestation associated with SS. After the TTP diagnosis, plasmapheresis and/or plasma exchange should be immediately implemented.

Scleroderma Renal Crisis Complicated with Thrombotic Microangiopathy Triggered by Influenza B Virus Infection

A 44-year-old Japanese man with a 14-year history of limited cutaneous systemic sclerosis (SSc) was admitted with a fever, hypertension, anemia, thrombocytopenia, and renal dysfunction. On admission, hypertension, hyperreninemia, acute renal dysfunction, hemolytic anemia, and thrombocytopenia led to the diagnosis of scleroderma renal crisis (SRC) complicated with thrombotic microangiopathy (TMA). The patient had also been infected with influenza B virus almost six days before admission. Following treatment with plasma exchange, an angiotensin-converting enzyme inhibitor, and an anti-virus agent, his general condition improved. He had no risk factors for SRC. In SSc patients, an influenza virus infection might trigger SRC complicated with TMA.

Thrombocytopenia in hospitalized patients: approach to the patient with thrombotic microangiopathy

Thrombotic microangiopathies (TMAs), specifically, thrombotic thrombocytopenic purpura (TTP) and complement-mediated hemolytic uremic syndrome (CM-HUS) are acute life-threatening disorders that require prompt consideration, diagnosis, and treatment to improve the high inherent mortality and morbidity. Presentation is with microangiopathic hemolytic anemia and thrombocytopenia (MAHAT) and variable organ symptoms resulting from microvascular thrombi. Neurological and cardiac involvement is most common in TTP and associated with poorer prognosis and primarily renal involvement in CM-HUS. TTP is confirmed by severe ADAMTS13 deficiency (which can be undertaken in real time) and CM-HUS by an abnormality in complement regulators, confirmed by mutational analysis (in 60% to 70% of cases) or the presence of Factor H antibodies (which may not be available for weeks or months). Plasma exchange (PEX) should be started as soon as possible following consideration of these TMAs. Differentiation of the diagnosis requires specific treatment pathways thereafter (immunosuppression primarily for TTP and complement inhibitor therapy for CM-HUS). As the diagnosis is based on MAHAT, there are a number of other medical situations that need to be excluded and these are discussed within the article. Other differentials presenting as TMAs may also be associated with micro- or macrovascular thrombosis, yet are more likely to be due to direct endothelial damage, many of which do not have a clear therapeutic benefit with PEX.

Aberrant coagulation causes a hyper-inflammatory response in severe influenza pneumonia

Influenza A virus (IAV) infects the respiratory tract in humans and causes significant morbidity and mortality worldwide each year. Aggressive inflammation, known as a cytokine storm, is thought to cause most of the damage in the lungs during IAV infection. Dysfunctional coagulation is a common complication in pathogenic influenza, manifested by lung endothelial activation, vascular leak, disseminated intravascular coagulation and pulmonary microembolism. Importantly, emerging evidence shows that an uncontrolled coagulation system, including both the cellular (endothelial cells and platelets) and protein (coagulation factors, anticoagulants and fibrinolysis proteases) components, contributes to the pathogenesis of influenza by augmenting viral replication and immune pathogenesis. In this review, we focus on the underlying mechanisms of the dysfunctional coagulatory response in the pathogenesis of IAV.