Indium‐labelled autologous platelet sequestration studies predict response to splenectomy in immune thrombocytopenia: an Australian experience

• Published in: Internal medicine journal 2022-08, Vol.52 (8), p.1387-1393
• Main Authors: Ratnasingam, Sumita, Reid, Amy S., Ma, Dickson, Bucki‐Smith, Daniel, Gwini, Stella M., Seneviratna, Leah, Campbell, Philip J.
• Format: Article
• Language: English
• Subjects: Idiopathic thrombocytopenic purpura; immune thrombocytopenia; indium scan; Patients; Platelets; Remission; Rituximab; Spleen; Splenectomy; Thrombocytopenia; Thrombopoietin
• ISSN: 1444-0903; 1445-5994
• DOI: 10.1111/imj.15344

Background Splenectomy is an effective intervention in primary immune thrombocytopenia (ITP). Attempts to define pre‐clinical predictors of platelet response to splenectomy are inconsistent. Based on international studies defining the likelihood of platelet response using platelet sequestration, patients with relapsed/refractory ITP being considered for splenectomy at a regional Australian hospital were assessed with 111indium‐labelled autologous platelet sequestration (ILAPS) studies. Aims To audit the use of ILAPS in an Australian setting and define its role in predicting response to splenectomy. Methods A retrospective review of all patients referred for an ILAPS study at a regional hospital was performed. Results for each patient were expressed as an ‘R’ value (spleen/ liver uptake ratio) to quantify the platelet sequestration pattern and outcome post‐splenectomy, based on platelet counts. Results A total of 45 patients was identified: 13 underwent splenectomy and 32 were medically managed. Patients with favourable ILAPS scans (pure or predominant splenic sequestration) demonstrated a superior response post‐splenectomy (100% overall response rate (ORR); 83.5% complete remission (CR)) compared with those with unfavourable ILAPS scans (mixed or pure hepatic sequestration) (71.4% ORR; 57.1% CR) over 12 months. Conclusions The use of ILAPS in the Australian setting is feasible and this experience confirms larger international studies demonstrating its utility as a predictor of response to splenectomy in ITP. An unfavourable ILAPS scan could be considered a negative predictor of response prompting consideration for other emerging ITP treatments such as thrombopoietin‐receptor agonists or B‐cell depleting therapy such as Rituximab.