ESPN 50th Annual Meeting

ESPN 2017


 
Five cases of group A streptococcus –associated C3 glomerulonephritis: pathological findings and response to treatment
MATSUMURA SOHSHI 1 Koichi Kamei 1 Yuji Kano 1 Mai Sato 1 Masao Ogura 1 Yu Kamigaki 2 Aya Inaba 2 Hiroyuki Machida 2 Takashi Oda 3 Shuichi Ito 4 Kenji Ishikura 1

1- NATIONAL CENTER FOR CHILD HEALTH AND DEVELOPMENT
2- Yokohama City University Medical Center
3- Tokyo Medical University Hachioji Medical Center
4- Yokohama City University
 
Introduction:

To clarify the hypothesis that group A streptococcus (GAS) infection could trigger C3 glomerulonephritis (C3GN).

Material and methods:

We retrospectively reviewed patients in whom C3GN was diagnosed at our institution between 2014 and 2016 based on the findings of a renal biopsy and the 2013 C3 glomerulopathy consensus report. We then performed immunofluorescent staining of nephritis-associated plasmin receptor (NAPlr) antigen, previously described as a nephritic antigen causing poststreptococcal acute glomerulonephritis, in order to extract patients among this population who were positive for NAPlr staining (Oda et al., J Am Soc Nephrol 2005).

Results:

Five patients with C3GN (3 boys; mean age: 11.2 years) were enrolled. The average duration of the follow-up was 23.2 months (range: 19-34). Urinalysis showed proteinuria and hematuria in all the patients. However, none had nephrotic syndrome. The renal function of all the patients was normal, but the serum C3 levels were below the normal range (12-26 mg/dL; normal range 80-140 mg/dL) despite normal serum C4. The serum titer of antistreptolysin O antibody (ASO) was elevated (315-527 IU/mL; normal range <240 IU/mL). GAS infection in three patients was confirmed by pharyngeal cultures. The patients’ renal pathological findings were consistent with typical C3GN. Furthermore, the glomeruli of all the patients showed positive staining for NAPlr. Three patients were treated with two courses of intravenous methylprednisolone pulse therapy (MPT) followed by oral prednisolone. The other two were given lisinopril. At the last visit, the proteinuria in the two patients treated with MPT showed improvement. However, with the exception of one patient treated with MPT, four of the patients showed persistent hypocomplementemia.

Conclusions:

Together with the elevated ASO, NAPlr staining of the glomeruli suggested an association between GAS infection and C3GN among a number of the patients. As with GAS-independent C3GN cases, those associated with GAS should be followed up over the long-term.