Evidence map›Paper›PMID 41307134›Full record

ArticleHaematologica2026

Divergent processing of FVIII light chain variants: secretory potential

Heike Singer, Payal Chawla, Katrin J Czogalla-Nitsche, Pujan Engels, Francesco Forin, Marc Sylvester, Melanie Rath, Jens Müller, Tobias Feist, Behnaz Pezeshkpoor and 3 more

Abstract read
In one paragraph

Article in Haematologica, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors.

Heike SingerInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Payal ChawlaInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Katrin J Czogalla-NitscheInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Pujan EngelsInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Francesco ForinInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Marc SylvesterMedical Faculty, Core Facility Mass Spectrometry, Institute of Biochemistry and Molecular Biology, University of Bonn, Bonn.
Melanie RathInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Jens MüllerInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Tobias FeistInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Behnaz PezeshkpoorInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Rawya Al-RifaiInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Osman El-MaarriInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn.
Johannes OldenburgInstitute of Experimental Haematology and Transfusion Medicine, University of Bonn. johannes.oldenburg@ukbonn.de.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

In 20-30% of severe hemophilia A (HA) patients, FVIII replacement therapy is hindered by inhibitory antibodies. Nonsense mutations in the FVIII light chain (A3-C1-C2) carry a higher risk of inhibitor formation than those in the heavy chain (A1-A2-B). The underlying molecular mechanism remains unclear. Using induced pluripotent stem (iPS) cells from HA patients, we developed two types of endothelial cell models, induced lymphatic endothelial cells (iLEC) and induced liver sinusoidal endothelial cells (iLSEC), that mimic native F8 mRNA expression and protein synthesis. Immunoassays detected FVIII protein in wild-type, intron 22 inversions (I22I), and two high inhibitor risk light chain variants (R1960X, R2228X). Co-staining with ER markers (PDI, BiP) revealed differential processing: R1960X exhibit enhanced proteasomal degradation with SEL1L, essential for MHC-I peptide loading, possibly contributing to higher immunogenicity. In contrast, R2228X showed a pattern more similar to wild-type, suggesting partial secretory potential. Although a mild co-localization with SEL1L was observed, it was not significant. Clinically, this patient did not develop inhibitors. In addition, exploratory in silico peptide binding predictions suggested that R1960X may generate a higher number of FVIII-derived epitopes presented via patient-specific HLA alleles compared to R2228X, further supporting differential immunogenicity. The I22I variant also showed detectable FVIII protein, which was deglycosylated and retained in the ER but did not co-localize with SEL1L; no inhibitor was observed in this case either. This cellular model shows reduced variability compared to primary cells, enabling patient-specific FVIII variant analyses, including intracellular processing, within the genetic background of the individual patient.

Indexed as

Factor VIIIHemophilia AProteasome Endopeptidase ComplexEndothelial CellsHumansInduced Pluripotent Stem CellsF8 protein, humanFactor VIIIProteasome Endopeptidase Complex

Identifiers

PMID41307134
PMCPMC13040200

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