Comparison of ADAMTS13 and Von Willebrand factor levels and activities, and plasminogen levels, in plasma products currently available for the treatment of thrombotic thrombocytopenic purpura in South Africa

Spontaneous recovery in a patient with acquired thrombotic thrombocytopenic purpura (TTP): observation of a 'subclinical' TTP state

OBJECTIVES

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy that can have high mortality rates without prompt treatment. Standard treatment is urgent plasma exchange (PLEX), which leads to disease remission in the vast majority of patients. Deficiency of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) alone is not sufficient to cause the clinical manifestations characteristic of TTP. We present a case of acquired TTP, where spontaneous recovery was observed prior to initiation of any TTP-specific therapy.

CLINICAL PRESENTATION

A 73-year-old asymptomatic female presented with new-onset mild haemolytic anaemia and thrombocytopenia. Further testing revealed a significantly reduced ADAMTS13 activity level and an ADAMTS13 inhibitor, concerning for acquired TTP. On reassessment, the patient's haematologic parameters had been corrected prior to initiation of therapy. During subsequent follow-up three months later, she developed acute worsening thrombocytopenia indicative of relapsed, acute TTP. The patient was then successfully managed with PLEX and rituximab and achieved a sustained remission.

DISCUSSION AND CONCLUSION

TTP is a haematologic emergency that requires urgent therapy to reduce morbidity and mortality. However, it is well documented that individuals with hereditary TTP and a proportion with acquired TTP in clinical remission can have low or nearly absent ADAMTS13 activity levels without evidence of microangiopathic haemolytic anaemia (MAHA) or thrombotic manifestations. Our patient represents a unique case of confirmed ADAMTS13 deficiency due to a documented inhibitor, leading to mild haemolytic anaemia and thrombocytopenia both of which recovered spontaneously. We propose that this scenario could represent a 'subclinical' TTP state that precedes the development of clinically significant disease.

Efficacy of albumin and compounded plasma for plasma exchange in acquired thrombotic thrombocytopenic purpura

INTRODUCTION

Thrombotic thrombocytopenic purpura (TTP) is a rare life-threatening thrombotic microangiopathy. Therapeutic plasma exchange (TPE) is the first-line treatment for TTP. In our institution, albumin plus plasma (fresh frozen plasma [FFP] and/or cryoprecipitate-reduced plasma [CRP]) has been used as replacement fluid since 2014. We aimed to evaluate the efficacy of albumin combined with plasma as TPE for TTP.

MATERIAL AND METHODS

We retrospectively evaluated 20 patients admitted to our institution due to an acute episode of TTP between January 1, 2014 and February 1, 2019. They were divided into two groups according to the replacement fluid protocols: (a) albumin plus FFP (1:1) and (b) albumin plus mixed plasma [ie, albumin and FFP with CRP (2:1:1)] groups. Data on patient characteristics, replacement parameters, outcome, and hemorrhage risk were collected and analyzed.

RESULTS

There were no significant differences in treatment outcomes between the two groups (P > .05). However, the albumin plus mixed plasma group tended to require fewer plasma exchanges (median, 4) and shorter time to response (median, 15 days) compared to albumin plus FFP group (median, 6; 31 days). Although the cumulative survival of the albumin plus mixed plasma group was higher than the other group starting from day 23 after treatment, we did not observe significant difference (P = .50). No significant increase in the risk for hemorrhage was observed in either group.

CONCLUSIONS

The therapeutic efficacy of albumin and mixed plasma (2:1:1) is not inferior to that of albumin and FFP (1:1), and it can be used in treating TTP.