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Abstract: TH-PO1109

Elucidating the Mechanism of Gross Hematuria in IgA Nephropathy: Analysis of the Biomarkers in Patients with Gross Hematuria After COVID-19 Vaccination

Session Information

  • COVID-19 - I
    November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Coronavirus (COVID-19)

  • 000 Coronavirus (COVID-19)


  • Aoki, Ryousuke, Juntendo Daigaku, Bunkyo-ku, Tokyo, Japan
  • Nihei, Yoshihito, Juntendo Daigaku, Bunkyo-ku, Tokyo, Japan
  • Matsuzaki, Keiichi, Kitasato Daigaku Igakubu, Sagamihara, Kanagawa, Japan
  • Kihara, Masao, Juntendo Daigaku, Bunkyo-ku, Tokyo, Japan
  • Suzuki, Hitoshi, Juntendo Daigaku, Bunkyo-ku, Tokyo, Japan
  • Suzuki, Yusuke, Juntendo Daigaku, Bunkyo-ku, Tokyo, Japan

Gross hematuria (GH) is observed shortly after an upper respiratory tract infection in 30–40% of the patients with immunoglobulin A nephropathy (IgAN), however, its mechanism is unclear. Recently, several reports showed the cases with GH after vaccination against coronavirus disease 2019 (COVID-19) in patients with IgAN. Here, we sought to clarify the mechanism of GH in IgAN by detailing the clinical characteristics and measuring serum and urinary galactose-deficient IgA1 (Gd-IgA1), which are known to be associated with development of IgAN, in patients with GH after COVID-19 vaccination. We conducted a prospective cohort study of 82 patients who presented with GH after COVID-19 vaccination.


All the patients visited either Juntendo University Hospital or Juntendo University Urayasu Hospital between May 11, 2021, and July 31, 2022. We collected the serum and urine samples at the time of the first presentation to the hospital with GH (GH 0) and six months after GH (GH 6). IgA1 were measured by enzyme-linked immunosorbent assays.


We found that majority of patients who developed GH after COVID-19 vaccination were females (58 patients, 71%). GH was observed after the second or subsequent vaccinations in most patients (75 patients, 92%). Among the 82 patients, 22 had been already diagnosed with IgAN or IgA vasculitis (IgAV) prior to vaccination. In the remaining 60 patients, 42 performed kidney biopsies, who were all diagnosed with IgAN or IgAV. Although serum Gd-IgA1 were comparable throughout the observation period (GH 0: 5135.7 ng/mL; interquartile range [IQR] 3930.3-6914.4 ng/mL vs. GH 6: 5354.8 ng/mL; IQR, 4288.5-7937.9 ng/mL; p=0.319), urinary Gd-IgA1 was increased at the time of GH (GH 0: 42.7ng/mL; IQR, 21.6-110.1 ng/mL vs. GH 6: 31.7ng/mL; IQR, 12.8-93.9 ng/mL; p=0.030). These data suggests that deposition of Gd-IgA1 in the glomeruli was enhanced by COVID-19 vaccination by a mechanism other than increasing serum Gd-IgA1.


Our cohort study suggests that GH in IgAN is triggered by some alternations in glomerulus itself that facilitate the deposition of Gd-IgA1. Increased incidence of GH after COVID-19 vaccination in females and after the second or subsequent vaccinations may help to clarify the mechanism of GH in detail.