Early Detection of Immune-Dysregulation Predicts a Better Response to Immunosuppressive Treatment in Chronic Immune Thrombocytopenia

Introduction: chronicimmune thrombocytopenia (ITP) is a highly heterogeneous condition in terms of clinical course and response to treatment and it could represent the epiphenomenon of a complex immune-dysregulation process. Not all patients respond with equal effectiveness to different therapeutic approaches. However, specific indicators to predict therapeuthic response to the most suitable second-line therapy (mycophenolate mofetile, sirolimus and TPO agonists) in the acute phase have not yet been identified.

Aims: to describe the clinical and immunological features and the treatment response in order to identify a group of clinical and immunological variables predictive of a response to a specific second-line therapy.

Methods: 72 paediatric patients with persistent or chronic ITP followed at Haematology Unit, Gaslini Children Hospital have been reviewed retrospectively. Our patients present a baseline assessment with extended analysis of lymphocyte subpopulations (immunophenotype), and a follow up of at least 6 months. In this cohort, 51 patients also have an assessment of response to a second-line therapy.

Results: signs of immune-dysregulation in the aute phase, such as an increased in double T negative lymphocytes (DNT), defined according to ALPS NIH 2009 criteria (>1,5%), a reduced in T-CD4 cells and NK cells compared to age reference values (rispectively p=0.05, 0<0.05 and p<0.05) and the simultaneous presence of ¾ positive parameter of the ALPS panel (DNT, T lymphocytes B220, memory B lymphocytes CD27 and CD3+CD25+/HLADR+ ratio) (p<0.05) predict a better response to immunomodulatory therapy than TPO agonists.

Conclusion: an early immonophenotypic characterisation at diagnosis represent an excellent tool to identify the best second-line therapy (immunomodulators or TPO-agonists); it is also crucial to guide an early indication to perform genetic studies in order to orientate the use of a possible target therapies.

Dufour:Sobi: Consultancy; Pfizer: Consultancy, Speakers Bureau; Gilead: Consultancy; Ono: Consultancy; Rockets: Consultancy; Novartis: Consultancy.