key: cord-0995543-8hmvwghy
authors: Morisawa, Kazumi; Honda, Masataka
title: Two patients presenting IgA nephropathy after COVID-19 vaccination during a follow-up for asymptomatic hematuria
date: 2022-03-29
journal: Pediatr Nephrol
DOI: 10.1007/s00467-022-05518-0
sha: c012ee0c05eb25de2dc11518b07f1fff971d4d59
doc_id: 995543
cord_uid: 8hmvwghy

nan

We read with great interest the report of a case of de novo immunoglobulin A nephropathy (IgAN) with gross hematuria following the use of an mRNA vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1] . In Japan, 27 cases of gross hematuria with related IgAN were reported following the use of an mRNA vaccine, but hitherto there have been no pediatric reports [2] . We herein report our experience of two pediatric patients with post-vaccination IgAN undergoing a follow-up for asymptomatic hematuria. Clinical information is shown in Table 1 .

Case 1 was a 16-year-old male with occult hematuria detected by a school urinalysis. Asymptomatic hematuria (RBC: 50-100/HPF) was diagnosed, and he was seen regularly at our outpatient clinic for 2 years. His mother had received a diagnosis of IgAN. On the day following his second vaccination, the patient experienced fever and gross hematuria. Three days post-vaccination, the gross hematuria resolved, but 6 days post-vaccination, the serum creatine and proteinuria values were 1.1 mg/dL and 0.28 g/g creatinine, respectively, with the former increasing to 1.26 mg/dL on day 20 post-vaccination. Based on a kidney biopsy, IgAN with mild proliferation of mesangial cells and cellular crescents was diagnosed (Oxford Score: M0E1S0T0C1).

From post-vaccination day 35, pulse methylprednisolone 1 g was administered for three consecutive days over two consecutive weeks followed by prednisolone 60 mg every 2 days. On day 55 after vaccination, serum creatinine had failed to improve to 1.29 mg/dL; therefore, prednisolone was administered daily for 4 weeks with the addition of azathioprine. Thereafter, prednisolone was reduced to 60 mg every other day, and then gradually reduced to a maintenance dose of 30 mg every other day. At present, 3 months after vaccination, serum creatinine has decreased to 1.05 mg/dL. Case 2 was that of a 13-year-old female patient in whom occult hematuria was detected by a school urinalysis. She was followed up for 2 months for the asymptomatic hematuria (RBC: 10-20/HPF). On the day after her second vaccination, she experienced fever and gross hematuria. Her urine protein-to-creatinine ratio rose to 1.99 g/g on day 7 postvaccination. Her gross hematuria gradually resolved. IgAN with mild proliferation of mesangial cells was diagnosed by kidney biopsy (Oxford Score: M0E0S0T0C0). Her proteinuria resolved on day 26 post-vaccination without treatment.

Both patients had only microscopic hematuria in the past and had been followed up regularly before their vaccination against SARS-CoV-2. They both experienced gross hematuria for the first time, and the serum creatinine in one patient increased with crescent formation.

The SARS-CoV-2 vaccine may make subclinical IgAN manifest. In a previous report, two cases of acute serum creatinine increase after vaccination were reported in children and were later diagnosed as de novo IgAN [1, 3] . In Matsuzaki et al., 19 cases of IgAN in 27 adult patients who experienced gross hematuria after vaccination were linked to a history of IgAN. A similar association may occur in pediatric patients. Thus, not only children who have already received the diagnosis of IgAN but also those with asymptomatic hematuria should be informed of the risks and benefits of COVID-19 vaccination to prevent complications.

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IgA nephropathy presenting as rapidly progressive glomerulonephritis following first dose of COVID-19 vaccine

Gross hematuria after SARS-CoV-2 vaccination: questionnaire survey in Japan

IgA nephropathy presenting as macroscopic hematuria in 2 pediatric patients after receiving the Pfizer COVID-19 vaccine

Acknowledgements We thank Tsutomu Takahashi, Riku Hamada, and Kentaro Matsuoka for their contributions to this report. We also thank Valera James Robert for his assistance with editing.

The authors declare no competing interests.