13 F with Nephrotic Range Proteinuria Patrick D. Walker, M.D.
History – 13 F with nephrotic range proteinuria –U P/C - 6.3 –Creatinine 1.1 mg/dl
– U/A 3+ protein, 2+ blood – Negative routine serologic studies – C3 and C4 WNL
Past History – No Significant Illnesses
Family History – Parents expired, cause not known – Three siblings with no medical illnesses
– All four live in an orphanage
Social History – Student – Actively participates in life at the orphanage
Physical Examination – Height – 165 cm; Weight – 41 kg (5’ 5”; 90 lbs) – Temp – normal – Blood Pressure 130/85 mmHg
– Respiratory rate – 14, Pulse – 68 beats/min – Edema of the lower extremities 1+ – No skin lesions, no organomegaly or lymphadenopathy – Systemic examination normal
Initial Laboratory Values – Creatinine 0.6 mg/dl – Serum albumin 2.2 – Normal urine output
– Urinalysis: 4+ protein, RBC: 2-5, WBC- 0-2, no casts, no crystals – 24 hour urine protein: 6.5 gm
Initial laboratory studies – Hematology –Mild iron deficiency anemia, normal WBC count and platelets
– Serologies –HIV, HbsAg and anti-HCV normal
–Complements normal –RA factor negative –Ultrasound R – 10.5 cm and L – 10 cm
–Normal echogenicity and corticomedullary junctions
Problem List
Problem List – Nephrotic syndrome
– Borderline hypertension
Differential Diagnosis
Renal Biopsy was performed
Immunofluorescence • 22 glomeruli with 0 globally sclerotic
IgG
C3
Kappa
Lambda
Electron Microscopy – Numerous subepithelial deposits with GBM ‘spikes’ – No subendothelial deposits – No mesangial deposits
– Diffuse foot process effacement
Summary • Light Microscopy
• Immunofluorescence Microscopy
• Electron Microscopy
Diagnosis
Diagnosis – Membranous Glomerulopathy, Stage 1 – Interstitial Fibrosis, Mild
– After the Diagnosis – Special stains were ordered – What Stains????
PLA2r
Comment – PLA2r positive – Correlates with the serologic studies and is a leading indicator for treatment response
APPENDIX
Membranous Glomerulopathy in Children – Uncommon in childhood – Falls under the group “Children with Nephrotic Syndrome” – also uncommon
Nephrotic Syndrome in Children – Incidence – 2-7 cases per 100,000/year – Prevalence – 16 cases per 100,000
– But, really need to sort these cases by age – Congenital < 1 year (genetic causes actually up to age 6) – Children 2 years through 12 years
– Teens 13 years through 19 years
Idiopathic Nephrotic Syndrome in Children
– Minimal Change Disease – Focal Segmental Glomerulosclerosis
– Membranous Glomerulopathy – < 5% –Very Misleading statistic! –Again, need to sort by age
Idiopathic Nephrotic Syndrome in Children – Minimal Change Disease – Focal Segmental Glomerulosclerosis – Membranous Glomerulopathy – < 5% –Ages 1 –12 years – >> Children –M>F::65%>35%
Membranous Glomerulopathy
– Clinical Syndrome –Most common cause of Idiopathic Nephrotic Syndrome – White Adults: MG – African American Adults: FSGS – Children: MCD
Membranous Glomerulopathy – It became clear over time that MG could be primary or secondary to a
variety of conditions – Secondary Causes more common – In Children 60 years
– MG almost always due to a Secondary Cause in Neonates
– Given the implications, this is critically important – What are these secondary associations?
Conditions Associated with MG Autoimmune Disease
Drugs|Chemicals Infections
Neoplasms Others
Conditions Associated with MG Infections
Autoimmune Disease
Others
Drugs|Chemicals Neoplasms
Conditions Associated with MG Infections Hepatitis B Hepatitis C Hydatid disease Parasitic disease Streptococcal infections Syphilis
Drugs|Chemicals Bucillamine Captopril Formaldehyde Gold Lithium 2-Mercaptoproprionly glycine Mercury NSAID Penicillamine Trimethadione
Autoimmune Disease ANCA-positive crescentic GN Anti-GBM disease Autoimmune enteropathy Primary biliary cirrhosis Chronic demyelinating radiculopathy Chronic thyroiditis Cryoglobulinemia Graves disease Hashimoto disease Lupus-like syndromes Mixed connective tissue disease Renal tubular antigen Renal tubular dysfunction Rheumatoid arthritis Sjögren's syndrome Systemic lupus erythematosus
Others Allogeneic stem cell transplant Autosomal dominant polycystic kidney disease Glomerular cystic disease Polyarteritis nodosa Renal vein thrombosis Sarcoid Sickle Cell Trait EVEN MORE NOT LISTED Neoplasms Carcinoma Melanoma Wilm’s tumor CLL Hodgkin’s disease Non-Hodgkin’s lymphoma
Modified from Heptinstall’s Pathology of the Kidney and AFIP Non-neoplastic Kidney Disease
QUESTION: From the following list, choose the one condition most likely to declare itself within the next year. Choose only one answer A.
Hodgkin Disease
B.
Sarcoidosis
C.
Hepatitis C Infection
D.
Lupus
E.
Polyarteritis Nodosa
QUESTION: From the following list, choose the one condition most likely to declare itself within the next year. Choose only one answer A.
Hodgkin Disease
B.
Sarcoidosis
C.
Hepatitis C Infection
D.
Lupus
E.
Polyarteritis Nodosa
Renal only Lupus – Less than 5% of patients with lupus present with renal-only
manifestations – Almost all of these have membranous glomerulopathy – Almost all (>95%) experience a lupus flare within one year of the development of renal disease
Phospholipase A2Receptor… What is going on? – Normal – A few PLA2r on the surface of podocytes
– IF is too insensitive to detect PLA2r in normal glomeruli
– PLA2r in MG – Marked increased in PLA2r on the surface of podocytes is likely, but… – There is also some change in the PLA2r since there are Anti-PLA2r antibodies in serum
Serum Test is excellent… – It was unknown if the renal biopsy could be used for PLA2r? – How sensitive and specific is PLA2r staining of the renal biopsy for
detection of primary MG?
PLA2r in Membranous – Arkana Labs Database examined for MG – Primary v Secondary determined – PLA2r antibody validated (multiple were available)
Membranous Glomerulopathy
– 165 biopsies available for inclusion – 80 cases of secondary MG – 85 of primary MG
– All had LM and IF – EM, 24 hour urine protein and serum creatinine were incorporated, when available
PLA2r Staining – FFPE- Enzyme pretreatment with protease K, 30 minutes
– Primary Antibody- PLA2r, Sigma-Aldrich, 1:50 (HPA012657 SIGMA), 30 minutes – Secondary Antibody- highly cross-adsorbed Alexa Fluor 488 goat anti-rabbit IgG, Life Technologies, 1:100 (A-11034), 30 minutes Larsen, CP, et al. Modern Pathol, 26: 709-715, 2013.
PLA2r Staining – FFPE- Enzyme pretreatment with protease K, 30 minutes
– Primary Antibody- PLA2r, Sigma-Aldrich, 1:50 (HPA012657 SIGMA), 30 minutes – Secondary Antibody- highly cross-adsorbed Alexa Fluor 488 goat anti-rabbit IgG, Life Technologies, 1:100 (A-11034), 30 minutes Larsen, CP, et al. Modern Pathol, 26: 709-715, 2013.
PLA2r by Immunofluorescence
PLA2r Positive
PLA2r Negative
PLA2r in Membranous Glomerulopathy – Diagnostic Utility of a Positive PLA2r on Biopsy – Only rarely are secondary causes found and these are likely unrelated to the presence of primary membranous – This limits the need for extensive screening
PLA2r in Membranous Glomerulopathy – Diagnostic/Treatment Utility –Determine if MG is due to anti-PLA2r antibodies using serum and/or the renal biopsy –If present, serum antibody levels can be used to monitor treatment and progression
Hoxha E, et al. J Am Soc Nephrol 2014; 25: 1357-1366.
Membranous Glomerulopathy – Other known causes of primary MG – Recall, only 70% of know primary MG is due to anti-PLA2r antibodies
