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Low anti-RhD IgG-Fc-fucosylation in pregnancy: a new variable predicting severity in haemolytic disease of the fetus and newborn.

ABSTRACT: Haemolytic disease of the fetus and newborn (HDFN) may occur when maternal IgG antibodies against red blood cells (RBCs), often anti-RhD (anti-D) antibodies, cross the placenta and mediate the destruction of RBCs via phagocytic IgG-Fc-receptors (Fc?R). Clinical severity is not strictly related to titre and is more accurately predicted by the diagnostically-applied monocyte-based antibody-dependent cellular cytotoxicity (ADCC), a sensitive test with relatively low specificity. This suggests that other factors are involved in the pathogenesis of HDFN. Binding of IgG to Fc?R requires the N-linked glycan at position 297 in the IgG-Fc-region, consisting of several different glycoforms. We therefore systematically analysed IgG-derived glycopeptides by mass spectrometry from 70 anti-D IgG1 antibodies purified from the plasma of alloimmunized pregnant women. This revealed a variable decrease in Fc-fucosylation in the majority of anti-D IgG1 (even down to 12%), whereas the total IgG of these patients remained highly fucosylated, like in healthy individuals (>90%). The degree of anti-D fucosylation correlated significantly with CD16 (Fc?RIIIa)-mediated ADCC, in agreement with increased affinity of defucosylated IgG to human Fc?RIIIa. Additionally, low anti-D fucosylation correlated significantly with low fetal-neonatal haemoglobin levels, thus with increased haemolysis, suggesting IgG-fucosylation to be an important pathological feature in HDFN with diagnostic potential.

SUBMITTER: Kapur R

PROVIDER: S-EPMC4282073 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature

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Low anti-RhD IgG-Fc-fucosylation in pregnancy: a new variable predicting severity in haemolytic disease of the fetus and newborn.

Kapur Rick R Della Valle Luciana L Sonneveld Myrthe M Hipgrave Ederveen Agnes A Visser Remco R Ligthart Peter P de Haas Masja M Wuhrer Manfred M van der Schoot C Ellen CE Vidarsson Gestur G

British journal of haematology 20140607 6

Haemolytic disease of the fetus and newborn (HDFN) may occur when maternal IgG antibodies against red blood cells (RBCs), often anti-RhD (anti-D) antibodies, cross the placenta and mediate the destruction of RBCs via phagocytic IgG-Fc-receptors (FcγR). Clinical severity is not strictly related to titre and is more accurately predicted by the diagnostically-applied monocyte-based antibody-dependent cellular cytotoxicity (ADCC), a sensitive test with relatively low specificity. This suggests that ...[more]

PMID: 24909983

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Project description:BackgroundClinical manifestations of hemolytic disease of the fetus and newborn include anemia, hyperbilirubinemia, hydrops fetalis, kernicterus, and fetal or neonatal demise. More than 50 antibodies are linked to hemolytic disease of the fetus and newborn, with Rhesus (including D and c) and Kell antigens carrying the highest risk of disease. To date, a multicenter, comprehensive evaluation of hemolytic disease of the fetus and newborn due to Rhesus antigen alloantibodies in the United States has not been undertaken.ObjectiveThis study aimed to implement a novel severity index to characterize the real-world disease spectrum of hemolytic disease of the fetus and newborn due to alloantibodies from the Rhesus class.Study designThis retrospective cohort study was conducted in neonates with commercial insurance available through Optum's deidentified Clinformatics® Data Mart Database (Clinformatics®) and Merative MarketScan® Commercial Claims and Encounters (CCAE) Database from 2000 to 2022. Neonatal and maternal records were linked algorithmically by shared family identifier. A hierarchical severity index was developed for neonates with a Rhesus antigen hemolytic disease of the fetus and newborn diagnosis code in the first 30 days of life, using antenatal and neonatal diagnoses and treatments: Severe (neonatal death, hydrops fetalis, intrauterine transfusion); Moderate (neonatal exchange transfusion); Mild (neonatal simple transfusion); Minimal (neonatal phototherapy or hyperbilirubinemia). Maternal, antenatal, and perinatal demographic and clinical characteristics were summarized descriptively by severity.ResultsIn Clinformatics® and Commercial Claims and Encounters Database, respectively, 1927 and 1268 neonates met the inclusion criteria. Most (93.1% Clinformatics®; 93.5% CCAE Database) displayed minimal severity, although in both databases nearly 40% of these neonates still required phototherapy. More neonates were mildly affected (3.3% Clinformatics®; 2.2% Commercial Claims and Encounters Database) than moderately (1.0% Clinformatics®; 1.1% Commercial Claims and Encounters Database). In Clinformatics® and Commercial Claims and Encounters Database, respectively, severe hemolytic disease of the fetus and newborn affected 2.6% and 3.2% of neonates, 54% and 46% of whom received exchange or simple transfusions. Severely affected neonates were more commonly delivered by cesarean delivery and at a lower gestational age (34.1 weeks Clinformatics®; 35.4 weeks Commercial Claims and Encounters Database) than those minimally affected (38.5 weeks Clinformatics®; 38.4 weeks Commercial Claims and Encounters Database).ConclusionResults across 2 real-world US databases found that although most neonates affected by hemolytic disease of the fetus and newborn due to Rhesus antigen alloantibodies did not require intervention beyond phototherapy, nearly 7% experienced disease severity requiring invasive intervention or resulting in neonatal mortality. More severely affected neonates had lower gestational age at birth, higher rates of cesarean delivery and neonatal intensive care unit admission, and longer length of hospital stay at birth compared with minimally affected neonates. The HDFN Severity Index is a useful tool to characterize hemolytic disease of the fetus and newborn and may be valuable alongside guideline-driven care in subsequent pregnancies.

Project description:BackgroundIn recent years the generation of antibodies by recombinant methods, such as phage display technology, has increased the speed by which antibodies can be obtained. However, in some cases when recombinant antibodies have to be validated, expression in E. coli can be problematic. This primarily occurs when codon usage or protein folding of specific antibody fragments is incompatible with the E. coli translation and folding machinery, for instance when recombinant antibody formats that include the Fc-region are needed. In such cases other expression systems can be used, including the protozoan parasite Leishmania tarentolae (L. tarentolae). This novel host for recombinant protein expression has recently shown promising properties for the expression of single-chain antibody fragments. We have utilised the L. tarentolae T7-TR system to achieve expression and secretion of two scFvs fused to the Fc-region of rabbit immunoglobulin G (IgG).ResultsBased on the commercial vector pLEXSY_IE-blecherry4 (Jena Bioscience; Cat. No. EGE-255), we generated a vector containing the Fragment Crystallisable (Fc) region of rabbit IgG allowing insertions of single chain antibody fragments (scFvs) in frame via Ncol/Notl cloning (pMJ_LEXSY-rFc). For the expression of rabbit Fc-fusion scFvs (scFv-rFc) we cloned two scFvs binding to human vimentin (LOB7 scFv) and murine laminin (A10 scFv) respectively, into the modified vector. The LOB7-rFc and A10-rFc fusions expressed at levels up to 2.95 mg/L in L. tarentolae T7-TR. Both scFv-rFcs were purified from the culture supernatants using protein A affinity chromatography. Additionally, we expressed three different scFvs without the rFc regions using a similar expression cassette, obtaining yields up to 1.00 mg/L.ConclusionsTo our knowledge, this is the first time that antibody fragments with intact Fc-region of immunoglobulin have been produced in L. tarentolae. Using the plasmid pMJ_LEXSY-rFc, L. tarentolae T7-TR can be applied as an efficient tool for expression of rFc fusion antibody fragments, allowing easy purification from the growth medium. This system provides an alternative in cases where antibody constructs express poorly in standard prokaryotic systems. Furthermore, in cases where bivalent Fc-fused antibody constructs are needed, using L. tarentolae for expression provides an efficient alternative to mammalian expression.

Dataset Information

Low anti-RhD IgG-Fc-fucosylation in pregnancy: a new variable predicting severity in haemolytic disease of the fetus and newborn.

Publications

Low anti-RhD IgG-Fc-fucosylation in pregnancy: a new variable predicting severity in haemolytic disease of the fetus and newborn.

Similar Datasets

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