Advantage of the subcutaneous immunoglobulin replacement therapy in primary immunodeficient patients with or without secondary protein loss.

Gür-Çetinkaya P, Çagdas-Ayvaz DN, Öksüz AB, Ertoy A, Hayran U, Özkan F, Erol M, Tezcan I. Advantage of the subcutaneous immunoglobulin replacement therapy in primary immunodeficient patients with or without secondary protein loss. Turk J Pediatr 2018; 60: 270-276. In recent years subcutaneous immunoglobulin is widely used for primary immunodeficient patients. Subcutaneous administration provides a more stable and higher serum immunoglobulin levels due to continuous and steady transition from lymphatics to the systemic circulation. We aimed to evaluate the changes in serum immunoglobulin levels under subcutaneous immunoglobulin therapy in patients with primary immunodeficiency with or without secondary protein loss. Nine patients with primary immunodeficiency who switched to subcutaneous immunoglobulin were enrolled. Age, gender, diagnosis, reasons of transition to subcutaneous route, reasons of secondary protein loss were recorded. A questionnaire consisting of frequencies and types of infections, side effects observed with intravenous and subcutaneous routes; date and reason of transition to subcutaneous route were asked to all participants. Serum immunoglobulin levels at the 3rd and the 6th months before and after subcutaneous route were recorded. Of the 9 patients (M/F=4/5) the median age was 12 years (6.1-28.7) and 5 of them had protein loss. In total, 444 injections were applied, and all patients experienced local reactions. Infections were more frequent under intravenous than subcutaneous route (p=0.004). We observed an increase in immunoglobulin levels under subcutaneous route (p=0.069 at 3rd; p=0.13 at 6th month). This increase was evident at the 3rd month of transition to subcutaneous route in patients with protein loss (p=0.080). There was an increase in serum immunoglobulin levels under subcutaneous route. However, increase was not statistically significant since the study group was small. This increment was prominent in patients with protein loss. Subcutaneous administration may be a good alternative for primary immunodeficient patients with protein loss who have persistent low serum immunoglobulin levels despite increments in the intravenous immunoglobulin doses.

Type I IFN-related NETosis in ataxia telangiectasia and Artemis deficiency.

BACKGROUND: Pathological inflammatory syndromes of unknown etiology are commonly observed in ataxia telangiectasia (AT) and Artemis deficiency. Similar inflammatory manifestations also exist in patients with STING-associated vasculopathy in infancy (SAVI). OBJECTIVE: We sought to test the hypothesis that the inflammation-associated manifestations observed in patients with AT and Artemis deficiency stem from increased type I IFN signature leading to neutrophil-mediated pathological damage. METHODS: Cytokine/protein signatures were determined by ELISA, cytometric bead array, or quantitative PCR. Stat1 phosphorylation levels were determined by flow cytometry. DNA species accumulating in the cytosol of patients' cells were quantified microscopically and flow cytometrically. Propensity of isolated polymorhonuclear granulocytes to form neutrophil extracellular traps (NETs) was determined using fluorescence microscopy and picogreen assay. Neutrophil reactive oxygen species levels and mitochondrial stress were assayed using fluorogenic probes, microscopy, and flow cytometry. RESULTS: Type I and III IFN signatures were elevated in plasma and peripheral blood cells of patients with AT, Artemis deficiency, and SAVI. Chronic IFN production stemmed from the accumulation of DNA in the cytoplasm of AT and Artemis-deficient cells. Neutrophils isolated from patients spontaneously produced NETs and displayed indicators of oxidative and mitochondrial stress, supportive of their NETotic tendencies. A similar phenomenon was also observed in neutrophils from healthy controls exposed to patient plasma samples or exogeneous IFN-α. CONCLUSIONS: Type I IFN-mediated neutrophil activation and NET formation may contribute to inflammatory manifestations observed in patients with AT, Artemis deficiency, and SAVI. Thus, neutrophils represent a promising target to manage inflammatory syndromes in diseases with active type I IFN signature.