A case of aggressive atypical anti-GBM disease complicated by CMV pneumonitis
Bibliographic record
Abstract
BACKGROUND: Anti-glomerular basement membrane (anti-GBM) disease is characterized by circulating IgG glomerular basement membrane antibodies and is clinically expressed as a rapidly progressive crescentic glomerulonephritis (GN), with 30-60% of patients also developing pulmonary hemorrhage. Classically, the renal biopsy shows glomerular crescent formation, bright linear staining of glomerular basement membranes (GBM) for IgG on direct immunofluorescence (IF), and the serologic presence of circulating anti-GBM antibodies. Recently, patients with linear IgG IF staining, undetectable circulating anti-GBM antibodies and glomerular changes atypical for anti-GBM disease have been described as "atypical anti-GBM disease", with a distinctly more benign clinical course than typical anti-GBM disease. We present a case report of a patient with negative anti-GBM serology but positive linear IgG staining by IF, severe diffuse crescentic and endocapillary proliferative glomerulonephritis, and renal failure, complicated by severe pulmonary hemorrhage after immunosuppression, likely due to cytomegalovirus (CMV) pneumonitis. CASE PRESENTATION: A 24-year-old man was admitted to hospital with hemoptysis and renal failure. Investigations for anti-GBM serology by addressable laser bead immunoassay (ALBIA) was negative for anti-GBM antibodies. Renal biopsy showed diffuse endocapillary proliferative glomerulonephritis with membranoproliferative features and diffuse circumferential crescents. Direct IF showed strong linear staining for IgG along GBMs. The patient's hemoptysis improved with immunosuppression, but 1 month later he was readmitted with gross hemoptysis, which was refractory to further cyclophosphamide, plasma exchange and rituximab. Bronchoalveolar lavage (BAL) and blood work confirmed CMV pneumonitis, and the patient's hemoptysis resolved with ganciclovir, though he became dialysis dependent. CONCLUSIONS: This case demonstrates an atypical presentation of anti-GBM disease with both crescents and endocapillary hypercellularity and negative serology. The patient is dialysis dependent, unlike most previously described patients with atypical anti-GBM disease. The course was complicated by CMV pneumonitis, which contributed to the severity of the pulmonary manifestations and added diagnostic difficulty.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".