Severe fetal anemia caused by <scp>anti‐Jr<sup>a</sup></scp>: Burst forming unit‐erythroid colony formation inhibition assay suggesting possible erythroid suppression mechanism
Bibliographic record
Abstract
Abstract Background The Jr blood group system includes a single, high‐prevalence antigen, Jra, encoded by the ABCG2 gene. The impact of anti‐Jra in pregnancy is variable, ranging from no clinical effect to severe anemia including some fetal deaths. Case reports have postulated that anti‐Jra mediated fetal anemia is poorly hemolytic, suggesting other mechanisms of anemia may be involved. Study Design and Methods We describe the case of severe anti‐Jra mediated fetal anemia. At Canadian Blood Services laboratories, maternal anti‐Jra was tested for phagocytic activity via a monocyte monolayer assay (MMA) and erythroid suppression via inhibition of burst forming unit‐erythroid (BFU‐E) colony formation assays. The New York Blood Center sequenced exons 4 and 7 of the ABCG2 gene. Results and Discussion Sequencing of exons 4 and 7 of the ABCG2 gene revealed maternal compound heterozygosity for two nonsense mutations at exon 7 (c.706 C > T and c.784G > T). Fetal sequencing revealed the c.706C > T polymorphism. The MMA showed a borderline phagocytic index (around the cutoff of five for both donor segments tested [5 ± 1 and 7 ± 3]). The BFU‐E colony formation inhibition assay suggested a dose‐dependent inhibition of BFU‐E colony formation with inhibition percentages of 4%, 11%, and 43% at maternal serum concentrations of 2%, 5%, and 10%, respectively. Our findings support the hypothesis that anti‐Jra may impair erythropoiesis leading to clinically significant fetal/neonatal anemia. A referral to maternal fetal medicine is recommended if anti‐Jra is detected in pregnancy, regardless of the titer.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".