D1.337 - Clinical features of patients submitted to immunoglobulin replacement therapy in an outpatient regimen at a tertiary hospital during 2024

Inborn errors of immunity and secondary hypogammaglobulinemia represent heterogeneous conditions characterized by impaired function of the immune system, leading to increased susceptibility to severe and recurrent infections. The replacement of human immunoglobulin (IgRt) can be intravenous (IVIG) or subcutaneous (SCIG) and is the cornerstone therapy for patients with impaired antibody production. The individualized choice of the administration route is essential to ensure the success of the treatment. 

This is a retrospective study that include patients who received IgRT between March 2024 and February 2025 in a tertiary hospital. Data were obtained through electronic medical records. Variables include: administration route, monthly dose, interval between applications and the presence of adverse events.

54 patients were included (72.2% male), total of 521 infusions: 60% IVIG, 39% SCIG, and 1% facilitated SCIG. The indications for IgRT were: Secondary hypogammaglobulinemia due to chronic kidney disease (7), common variable immunodeficiency (6), X-linked agammaglobulinemia (5), prematurity (5), undefined hypogammaglobulinemia (5), Hyper-IgM syndrome (4), Wiskott-Aldrich syndrome (3), DiGeorge syndrome (3), secondary to lymphatic loss (3), secondary to infectious conditions (3), secondary to nephrotic syndrome (3), secondary to Down syndrome (2), ataxia-telangiectasia (1), X-linked ichthyosis (1), APLS-like syndrome (1), secondary to protein-losing enteropathy (1), and secondary to chemotherapy (1). The mean monthly dose was 541 mg/kg. Among IVIG users, 84.2% received infusions every four weeks, while the remaining received them every three weeks. In the SCIG group, 56% had biweekly infusions, and the others received them weekly. Both IVIG and SCIG infusions were safe and well tolerated, with no severe adverse events. 

IVIG was predominant, due to the availability of the medication in the public health system and to the patients´ choice. There were only mild adverse events such as headache and asymptomatic hypertension.  SCIG demonstrated good adherence and tolerance and it was the preferable choice for patients with hypogammaglobulinemia secondary to protein loss (renal, intestinal, lymphatic), ensuring more stable levels of IgG. Although there are challenges in the access of subcutaneous formulations, it is essential to individualize the therapy for each patient to assure effective control of the disease.