Thrombocytopenia in patients with inborn errors of immunity.

Background: Inborn errors of immunity (IEI) are inherited defects of innate or adaptive immune system. Thrombocytopenia is a significant multifactorial complication in IEI patients leading to severe clinical consequences including coagulative disorders and vasculopathies.

Methods: In the present study, we assessed frequency of thrombocytopenia in the most common IEI including combined immunodeficiency (CID), common variable immunodeficiency (CVID), selective immunoglobulin A deficiency (SIgAD), agammaglobulinemia (AGA), hyper immunoglobulin M (HIGM) syndrome, chronic granulomatous disease (CGD) and congenital neutropenia (CN). Also, we compared demographic, clinical and laboratory data between IEI patients with and without thrombocytopenia.

Results: A total of 890 patients (37% female) were included in this study. The frequency of thrombocytopenia in total IEI was 26.6%. Patients with CID and SIgAD had the highest and lowest frequency of thrombocytopenia (50.9% and 8.7%), respectively. Although rare, thrombocytopenia was more severe (< 50000/ul) among patients with AGA compared to other IEI entities. Notably hepatosplenomegaly and autoimmunity were significantly associated with thrombocytopenia and higher mortality in patients with humoral immunodeficiencies.

Conclusion: The significant association between thrombocytopenia with lymphoproliferation and autoimmunity emphasizes the importance of paying attention to these clinical features for suspecting IEI disorders. Understanding the pathophysiology of thrombocytopenia in various genetic defects associated with IEI is required for the development of proper diagnostic and therapeutic techniques as well as improved quality of life of these patients.