Comparison of Demographic and Clinical Characteristics among X-Linked and Autosomal Recessive Agammaglobulinemia

Background: Congenital agammaglobulinemia is an inborn error of immunity, resulting in the impairment of effective antibody production. Agammaglobulinemia may be due to X-linked or autosomal genetic abnormalities. The primary defect in X-Linked agammaglobulinemia (XLA) and autosomal recessive agammaglobulinemia (ARAG) is the B cell precursors’ failure to mature B-lymphocytes and, ultimately, plasma cells. This study aims to evaluate the differences in clinical and paraclinical characteristics of XLA and ARAG patients. Method: A total of 58 patients were enrolled in this retrospective study. The data were extracted from the Iranian primary immunodeficiency registry (IPIDR). Forty-eight of the patients were diagnosed with XLA, while the other ten were diagnosed with ARAG. Measures including demographic data, clinical manifestations, and laboratory data of the patients were compared between the groups. Results: Patients with ARAG, presented manifestations at an earlier age and had a lower diagnosis delay compared to XLA patients. However, the mortality rate was not significantly affected. The pattern of organ involvement also differed between the two groups, as patients with ARAG showed manifestations that are more chronic in nature (e.g., autoimmunity, lymphoproliferation, and allergy). In contrast, XLA patients were more prone to infections and other associated complications (e.g., meningitis, sinusitis, diarrhea, and bronchiectasis). Meningitis was exclusively observed in the XLA group. The number of CD19+ B cells was significantly higher in the ARAG group (P=0.002), While the level of IgM was significantly higher in the XLA group (P=0.045). Conclusion: Identifying the clinical presentations of XLA and ARAG, may assist clinicians in early diagnosis in the setting of limited available genetic studies.