Immune Thrombocytopenia in Two Unrelated Fanconi Anemia Patients - A Mere Coincidence?

Primary Immunodeficiency and Thrombocytopenia

Primary immunodeficiency (PID) or Inborn errors of immunity (IEI) refers to a heterogeneous group of disorders characterized by immune system impairment. Although patients with IEI manifest highly variable symptoms, the most common clinical manifestations are recurrent infections, autoimmunity and malignancies. Some patients present hematological abnormality including thrombocytopenia due to different pathogenic mechanisms. This review focuses on primary and secondary thrombocytopenia as a complication, which can occur in IEI. Based on the International Union of Immunological Societies phenotypic classification for IEI, the several innate and adaptive immunodeficiency disorders can lead to thrombocytopenia. This review, for the first time, describes manifestation, mechanism and therapeutic modalities for thrombocytopenia in different classes of IEI.

Treatment of immune-mediated cytopenias in patients with primary immunodeficiencies and immune regulatory disorders (PIRDs)

Severe immune cytopenias (SICs) are rare acquired conditions characterized by immune-mediated blood cell destruction. They may necessitate emergency medical management and long-term immunosuppressive therapy, strongly compromising the quality of life. The initial diagnostic workup involves excluding malignancies, congenital cytopenias, bone marrow failure syndromes, infections, and rheumatologic diseases such as systemic lupus erythematosus. Causal factors for SIC such as primary immunodeficiencies or immune regulatory disorders, which are referred to as inborn errors of immunity (IEIs), should be diagnosed as early as possible to allow the initiation of a targeted therapy and avoid multiple lines of ineffective treatment. Ideally, this therapy is directed against an overexpressed or overactive gene product or substitutes a defective protein, restoring the impaired pathway; it can also act indirectly, enhancing a countermechanism against the disease-causing defect. Ultimately, the diagnosis of an underling IEI in patients with refractory SIC may lead to evaluation for hematopoietic stem cell transplantation or gene therapy as a definitive treatment. Interdisciplinary care is highly recommended in this complex patient cohort. This case-based educational review supports decision making for patients with immune-mediated cytopenias and suspected inborn errors of immunity.