Delineating the Clinical and Immunologic Characteristics: A Comparative Study of Inborn Errors of Immunity in Adult versus Pediatric Diagnosed

Abstract

Introduction: Inborn errors of immunity (IEIs) are rare genetic disorders primarily identified in children due to their significant effects on immune system functionality. However, an increasing number of IEI cases are being diagnosed in adults, attributed to delayed presentation or advancements in diagnostic capabilities. This study explores the clinical and immunologic distinctions between IEIs diagnosed in adulthood versus childhood, shedding light on their differential presentations, the impact of diagnostic delays, and treatment outcomes.

Methods: This study focused on 122 adult patients with IEI above 17 years old, diagnosed in adulthood or childhood. We collected comprehensive data on demographics, clinical presentations, genetic mutations, and therapeutic interventions.

Results: The study revealed that 72.9% of participants were diagnosed in adulthood, facing a median diagnostic delay of 96 months. Diagnostic delays were longer in adults (132 months vs. 24 months) than in children. The most common clinical manifestations at onset were recurrent infections (46.7%) and autoimmunity (18%). Predominantly antibody deficiency was the most frequently diagnosed immunodeficiency (54.9%), followed by immunodysregulation at a rate of 26.2%. A higher incidence of immune thrombocytopenia or other complications, such as hepatomegaly and enteropathy, was observed in adult-diagnosed patients with IEI. Malignancies were more prevalent in patients with adult-onset IEI compared to those with childhood-onset (18.1% vs. 5.2%). Overall, 15 different malignancies were recorded in 13 patients (10.6%), including lymphomas and cancers of the stomach, thymus, skin, breast, and colon.

Conclusions: The findings highlight a considerable diagnostic delay in recognizing IEI, especially in adults, and illustrate distinct differences in disease manifestation and progression between adult-onset and delayed-diagnosis groups.

Keywords: Adult primary immunodeficiency; Immune dysregulation; Inborn errors of immunity; Malignancy.