Anti-GBM disease without antibodies following H1N1 infection: A seronegative variant or an atypical entity?

A female in her mid-twenties presented with fever and a dry cough for 15 days, following which she developed rapidly progressive glomerulonephritis culminating in anuria.She had a tattoo made 10 days earlier.She denied any smoking in the recent past, though she did acknowledge a few days of recreational smoking several months earlier.Nasopharyngeal swab reverse transcription polymerase chain reaction was positive for H1N1, influenza A, and B.She was isolated and initiated on hemodialysis.Her urinary lead, cadmium, and chromium levels were elevated.She was given an injection of ethylenediaminetetraacetic acid and three sessions of hemoperfusion with no clinical improvement.Kidney biopsy [Figure 1] was suggestive of crescentic glomerulonephritis (11/20 cellular and 5/20 fibrocellular crescents) with linear immunoglobulin G (IgG) deposits https://jlabphy.org/