100163 - Comparison Of Clinical Features In Primary Immunodeficiency Patients With And Without Autoimmunity Or Autoinflammation

Primary immunodeficiencies (PIDs) are a heterogeneous group of disorders characterized by impaired immune function. While infections are the hallmark feature, non-infectious complications such as autoimmunity, autoinflammation, lymphoproliferation, and malignancies are also increasingly recognized. These immune dysregulation patterns may appear at any point during the disease course and may contribute to morbidity and diagnostic delay. However, comparative studies evaluating the clinical profiles of PID patients with versus without such manifestations remain limited.

To determine the prevalence of autoimmune and autoinflammatory features in patients with PID, compare their clinical, laboratory, and immunological characteristics, and assess potential prognostic differences. 

 A total of 130 adult PID patients followed in a tertiary university immunology clinic were retrospectively analyzed. Based on clinical findings, patients were categorized into three groups: Group 1: No autoimmune or autoinflammatory findings , Group 2: Presence of autoimmune manifestations (e.g., autoimmune cytopenia, thyroiditis, hepatitis, alopecia, type 1 diabetes, celiac disease) , Group 3: Presence of autoinflammatory features (e.g., familial Mediterranean fever, Behçet disease, inflammatory bowel disease, NLRC4 mutation).Data on demographics, laboratory parameters, immunoglobulin levels, lymphocyte subsets, switched memory B cells, and genetic mutations were collected. Statistical comparisons were performed using non-parametric and categorical tests with Bonferroni correction for post-hoc analysis. 

Autoimmunity was observed in 32.3% and autoinflammation in 9.2% of patients.Group 3 showed significantly higher levels of CRP, ESR, and fibrinogen (p < 0.05), reflecting heightened systemic inflammation. Platelet counts were significantly lower in Group 2, possibly due to autoimmune cytopenias (p = 0.001). Serum IgE levels were significantly reduced in autoimmune patients (p = 0.007), while IgG, IgA, and IgM did not show significant differences. Switched memory B cells (CD19⁺CD27⁺IgD⁻) were markedly lower in Group 2 (p = 0.005), supporting their association with autoimmune susceptibility.No significant differences in genetic mutation types or mortality were observed across the groups. 

Autoimmune and autoinflammatory manifestations are prevalent among PID patients and are associated with distinct inflammatory and immunological patterns. Low IgE and reduced switched memory B cells may serve as useful markers for early identification of autoimmunity. Routine screening for immune dysregulation should be integrated into the diagnostic and long-term management strategies of PID.