Abstract / Summary
Abstract Immunoglobulin G subclass deficiency (IgGSD) is a heterogeneous antibody deficiency associated with recurrent sinopulmonary infections in children. This prospective study characterized the clinical, immunological, and genetic features of pediatric IgGSD patients receiving immunoglobulin replacement therapy (IgRT) and evaluated its impact on quality of life (KINDL-R) and treatment satisfaction (TSQM-9). Forty-four pediatric patients (30 males, 14 females; median age 78 months) started on regular IgRT were enrolled. Baseline clinical, lymphocyte-subset, and next-generation sequencing data were recorded; age-specific KINDL-R questionnaires were administered at baseline and Month 12, and treatment satisfaction was assessed with the TSQM-9 at Month 12, with all scores standardized to a 0-100 scale. Combined IgG2 + IgG3 deficiency was the most frequent pattern (34.1%), and the risk of lower respiratory tract infection was significantly higher with IgG2 deficiency (p = 0.021). Absolute CD3 + T-cell counts were reduced for age in 29.7% of patients, and primary immunodeficiency-associated genetic variants (e.g., NFKB1, TNFRSF13B, TCF3) were detected in 52.9% of those tested. After 12 months of IgRT, the mean KINDL-R score increased from 64.79 to 74.45 (p < 0.001), while TSQM-9 Effectiveness was high (79.67) and Global Satisfaction was comparatively lower (59.09), reflecting the burden of intravenous administration. Baseline IgGSD phenotype did not significantly affect the magnitude of quality-of-life improvement (p > 0.05). IgGSD is a complex entity that may involve genetic variants and cellular immune defects. IgRT exerts an equalizing effect that improves quality of life regardless of baseline immunological disadvantage, but intravenous administration limits global satisfaction, supporting consideration of subcutaneous immunoglobulin and routine use of patient-reported outcome measures.