Quality of Life Evaluation in Saudi Arabian Pediatric Patients with Primary Immunodeficiency Diseases Receiving 20% Subcutaneous IgG Infusions at Home.

BACKGROUND AND AIMS: Subcutaneous immunoglobulin (SCIG) home infusion is widely used as an alternative to intravenous immunoglobulin (IVIG). This study aimed to determine the quality of life (QoL) of patients with primary immunodeficiency (PID) after switching to home-based SCIG. METHODS: In this prospective open-label single-center study, QoL was determined using the validated Arabic version of the Child Health Questionnaire at baseline and 3 and 6 months after switching from IVIG to SCIG. RESULTS: Twenty-four patients were recruited from July 2018 to August 2021, including 14 females and 10 males. The median age of the patients was 5 years (range, 0-14 years). The patients' diagnoses included severe combined immunodeficiency, combined immunodeficiency, agammaglobulinemia, Omenn syndrome, immunodysregulation, hyper-IgE syndrome, common variable immunodeficiency, and bare lymphocyte syndrome. The median duration on IVIG before inclusion was 40 months (range, 5-125 months). The QoL score showed a significant improvement in the patients' global health at 3 and 6 months compared with those at baseline and a significant improvement in the patients' general health at 3 and 6 months compared with that at baseline. The mean baseline serum IgG trough level was 8.8 ± 2.1 g/L. The mean serum IgG level was significantly higher on SCIG at both 3 and 6 months (11.7 ± 2.3 and 11.7 ± 2.5 g/L, respectively). CONCLUSIONS: This is the first study involving an Arab population to show improvement in the QoL of patients with PID after switching from hospital-based IVIG to home-based 20% SCIG.

Rituximab-induced hypogammaglobulinemia and infection risk in pediatric patients.

BACKGROUND: Rituximab is a B-cell depleting agent used in B-cell malignancies and autoimmune diseases. A subset of adult patients may develop prolonged and symptomatic hypogammaglobulinemia following rituximab treatment. However, this phenomenon has not been well delineated in the pediatric population. OBJECTIVES: This study sought to determine the prevalence, risk factors, and clinical significance of hypogammaglobulinemia following rituximab therapy in children. METHODS: This was a multicenter, retrospective cohort study that extracted clinical and immunological data from pediatric patients who received rituximab. RESULTS: The cohort comprised 207 patients (median age, 12.0 years). Compared to baseline values, there was a significant increase in hypogammaglobulinemia post-rituximab therapy, with an increase in prevalence of hypo-IgG (28.7%-42.6%; P = .009), hypo-IgA (11.1%-20.4%; P = .02), and hypo-IgM (20.0%-62.0%; P < .0001). Additionally, low IgG levels at any time post-rituximab therapy were associated with a higher risk of serious infections (34.4% vs 18.9%; odds ratio, 2.3; 95% CI, 1.1-4.8; P = .03). Persistent IgG hypogammaglobulinemia was observed in 27 of 101 evaluable patients (26.7%). Significant risk factors for persistent IgG hypogammaglobulinemia included low IgG and IgA levels pre-rituximab therapy. Nine patients (4.3%) within the study were subsequently diagnosed with a primary immunodeficiency, 7 of which received rituximab for autoimmune cytopenias. CONCLUSIONS: Hypogammaglobulinemia post-rituximab treatment is frequently diagnosed within the pediatric population. Low IgG levels are associated with a significant increase in serious infections, and underlying primary immunodeficiencies are relatively common in children receiving rituximab, thus highlighting the importance of immunologic monitoring both before and after rituximab therapy.

Prolidase deficiency, a rare inborn error of immunity, clinical phenotypes, immunological features, and proposed treatments in twins.

BACKGROUND: Prolidase deficiency (PD) is an autosomal recessive inborn multisystemic disease caused by mutations in the PEPD gene encoding the enzyme prolidase D, leading to defects in turnover of proline-containing proteins, such as collagen. PD is categorized as a metabolic disease, but also as an inborn error of immunity. PD presents with a range of findings including dysmorphic features, intellectual disabilities, recurrent infections, intractable skin ulceration, autoimmunity, and splenomegaly. Despite symptoms of immune dysregulation, only very limited immunologic assessments have been reported and standard therapies for PD have not been described. We report twin females with PD, including comprehensive immunologic profiles and treatment modalities used. CASE PRESENTATION: Patient 1 had recurrent infections in childhood. At age 13, she presented with telangiectasia, followed by painful, refractory skin ulcerations on her lower limbs, where skin biopsy excluded vasculitis. She had typical dysmorphic features of PD. Next-generation sequencing revealed pathogenic compound heterozygous mutations (premature stop codons) in the PEPD gene. Patient 2 had the same mutations, typical PD facial features, atopy, and telangiectasias, but no skin ulceration. Both patients had imidodipeptiduria. Lymphocyte subset analysis revealed low-normal frequency of Treg cells and decreased frequency of expression of the checkpoint molecule CTLA-4 in CD4+ TEM cells. Analysis of Th1, Th2, and Th17 profiles revealed increased inflammatory IL-17+ CD8+ TEM cells in both patients and overexpression of the activation marker HLA-DR on CD4+ TEM cells, reflecting a highly activated proinflammatory state. Neither PD patient had specific antibody deficiencies despite low CD4+CXCR5+ Tfh cells and low class-switched memory B cells. Plasma IL-18 levels were exceptionally high. CONCLUSIONS: Immunologic abnormalities including skewed frequencies of activated inflammatory CD4+ and CD8+ TEM cells, decreased CTLA-4 expression, and defects in memory B cells may be a feature of immune dysregulation associated with PD; however, a larger sample size is required to validate these findings. The high IL-18 plasma levels suggest underlying autoinflammatory processes.