A case of post-pneumococcal acute glomerulonephritis with glomerular depositions of nephritis-associated plasmin receptor

Abstract

We report the case of a 12-year-old girl who was referred to our hospital with anuria associated with pneumonia. On admission, the patient's blood test results revealed severe renal failure, hypoproteinemia, and hypocomplementemia. Her urinalysis results revealed hematuria, proteinuria, and a positive titer for Streptococcus pneumoniae. S. pneumoniae was also detected in her sputum and blood cultures. The patient was diagnosed with post-pneumococcal acute glomerulonephritis (AGN) with acute renal failure. A renal biopsy demonstrated the infiltration of neutrophils and mononuclear cells into capillary loops. Immunofluorescence studies showed dominant-positive deposition of C3c along the capillary loops and nephritis-associated plasmin receptor (NAPlr) depositions in the mesangial area and capillary loops. Electron microscopy revealed dense deposits in the glomerular basement membrane without a hump in the subepithelial area. These findings were consistent with endocapillary proliferative glomerulonephritis. AGN associated with pneumococcal infection is very rare. This case suggests that NAPlr is the causative antigen not only of post-streptococcal AGN, but also of post-pneumococcal AGN. To our knowledge, this is the first report that shows a relationship between post-pneumococcal AGN and NAPlr depositions in the glomeruli.

Glomerular Deposition of Nephritis-Associated Plasmin Receptor (NAPlr) and Related Plasmin Activity: Key Diagnostic Biomarkers of Bacterial Infection-related Glomerulonephritis

“…Interestingly, glomerular NAPlr deposition and plasmin activity have recently been demonstrated in patients with IRGN induced by some bacterial strains, such as Streptococcus pneumoniae [28], Aggregatibacter actinomycetemcomitans (a Gram-negative coccobacillus that sometimes causes periodontal disease and infectious endocarditis) [29], Mycoplasma pneumoniae [30], or S. aureus (both methicillin-sensitive and -resistant strains; unpublished observations). The sequences of S. pneumoniae GAPDH share high identity with NAPlr, and the C-terminal sequences of S. pneumoniae GAPDH, which are most likely to be associated with the plasmin-binding activity, are completely identical to those of streptococcal GAPDH [28]. M. pneumoniae GAPDH has been shown to not only have cross-immunoreactivity to the anti-NAPlr antibody but also to have a plasmin-binding function.…”

Post-infectious Proliferative Glomerulonephritis with Monoclonal Immunoglobulin G Deposits Associated with Complement Factor H Mutation

“…Glomerular deposition of NAPlr is usually seen in the early phase of acute poststreptococcal glomerulonephritis and pathogenically causes glomerular damage by trapping plasmin and maintaining its activity ( 7 ). However, NAPlr deposition is observed in other glomerular diseases as well, such as dense deposit disease or MPGN after streptococcal infection ( 13 ), and even after other bacterial infections such as pneumococcal infection ( 14 ) or staphylococcal infection (unpublished data). NAPlr is basically identical to streptococcal glyceraldehyde-3-phosphate dehydrogenase (GAPDH) ( 7 ).…”

Galactose-deficient IgA1 and nephritis-associated plasmin receptors as markers for IgA-dominant infection-related glomerulonephritis

“…NAPlr is a nephritogenic protein isolated from group A streptococcus (GAS). Recent reports also describe positive NAPlr staining in IRGN induced by bacteria Streptococcus pneumoniae , [ 6 ] Aggregatibacter actinomycetemcomitans (a component of the Gram-negative oral flora), [ 7 ] and Mycoplasma pneumoniae . [ 8 ] Therefore, NAPlr and plasmin activity have been proposed as the general biomarkers of bacterial IRGN.…”