Introduction Immunoglobulin represents the main therapy for patients with inborn errors of immunity (IEI) and it is a safe procedure, but adverse events (AEs) can occur with variable frequencies. Objective To evaluate the frequency of immediate AEs to intravenous immunoglobulin (IVIG) regular therapy in a pediatric cohort with IEI after a pre-IVIG infusion protocol. Methods This was a longitudinal study from 2011 to 2019 at a tertiary pediatric hospital in Brazil. Results A total of 1736 infusions were studied in 70 patients with IEI, 46 (65.7%) of whom were males and whose median age was 5.8 years old (range: 6 mo - 18 yo). Seven different brands of IVIG were used with the median loading dose of 0.57g/kg (range: 0.23 - 0.88g/Kg). According to the protocol, pre-medication and step-up infusion rate, were performed in 1305 (75.2%) infusions. Immediate AEs were noted in 10 children (14.3%) and in 22 (1.2%) infusions. Skin reactions (rash or urticaria) were the most common AE with 14 episodes (0.8% of all infusions). Almost all AEs were mild (19/86.4%), with no severe ones being observed. The majority of the AEs (81.8%) was identified at a 0.04ml/kg/min infusion rate. Gender, age at first infusion, presence of infection on the infusion day and change of the IVIG brand were evaluated and none of them were associated with AEs. Conclusion The low frequency of immediate AEs in children with IEI highlights the safety and tolerability of intravenous immunoglobulin replacement with the procedures established at our center.

Abstract Objectives: To compare the frequency of hospitalization in children with Inborn Errors of Immunity with antibody deficiency previous to intravenous immunoglobulin (pre- IVIG) with a one-year period after initial IVIG (post-IVIG). Methods: Medical reports of 45 patients during an eight-year period were reviewed from 2018 to 2019. Wilcoxon-test was used for related samples. Results: Forty-five children were included in the study, aged 29-249 months of age, and most of them (64.4%) were males. Median ages at onset symptoms and at diagnosis were 6 and 73 months old, respectively. Specific antibody deficiency and unclassified hypogammaglobulinemia were the predominant diagnoses (31.1% and 17.8%, respectively). X-linked agammaglobulinemia, Hyper IgE syndrome, Hyper IgM, transient hypogammaglobulinemia of infancy, and Common Variable Immunodeficiency (CVID) were also reported, in a low frequency. Forty-four (97.8%) patients were hospitalized before IVIG, and 10 patients (22.2%) after. Annual mean hospital admission reduced from 2.5 to 0.5, pre and post-IVIG, respectively (p < 0.0001). Mean length of stay (LOS) reduced from 71 to 4.7 days/year (p < 0.0001) in general ward and in the PICU from 17.2 days/year to zero (p < 0.0002). Pneumonia was the main cause of hospital admission with a reduction in the number of episodes per patient from an average of 2.2–0.1 per year (p < 0.001). Concomitant use of antibiotic prophylaxis did not influence the number of hospital admission. Conclusion: One-year intravenous IVIG significantly decreased the number of hospitalizations and length of stay in children with impaired antibody production. Social and economic impacts would be required.