Anti-Tumor Necrosis Factor Treatment for Glomerulopathy: Case Report and Review of Literature
Background: Glomerulopathy involves damage to the glomerular filtration barrier for several reasons, resulting in idiopathic nephrotic syndrome (NS). Treatment options are limited and often include steroids with varying levels of response.
Case Presentation: A 7-year-old male with a history of NS at age 2 years that developed following a respiratory tract infection was found to have a heterozygous variant of uncertain significance in COL4A4 and TRPC6 genes. Biopsy findings included podocytopathy and changes in the basement membrane. Upon initial response to steroids, the patient was treated with a brief course of anakinra followed by adalimumab for > 2 years as steroid-sparing biological response modifiers. After a gradual taper, the patient remains in remission and has not received treatment in the last 12 months.
Conclusions: This case shows the complex nature of biologically predetermined cascading events in the emergence of glomerular disease with environmental triggers and genetic factors. Downregulation of somatic tissue-driven proinflammatory milieu originating from the constituents of the glomerular microenvironment can help in recovery from emerging podocytopathy. Blocking tumor necrosis factor-α early in the disease course, even temporarily, may allow time for the de novo regenerative process to prevail. Additional research is warranted to test this hypothesis and minimize steroid use.
The patient’s initial laboratory results included: complete blood count with white blood cells (WBC) 10 x 103/L (reference range, 4.5-13.5 x 103/L); differential lymphocytes 69%; neutrophils 21%; hemoglobin 10 g/dL (reference range, 12-16 g/dL); hematocrit, 30%; (reference range, 37%-45%); platelets 437 103/L (reference range, 150-450 x 103/L); serum creatinine 0.46 mg/dL (reference range, 0.5-0.9 mg/dL); and albumin 3.1 g/dL (reference range, 3.5-5.2 g/dL). Serum electrolyte levels and liver enzymes were normal. A urine analysis revealed 3+ protein and 3+ blood with dysmorphic red blood cells (RBC) and RBC casts without WBC. The patient's spot urine protein-to-creatinine ratio was 4.3 and his renal ultrasound was normal. The patient was referred to Nephrology.
During the next 2 weeks, his protein-to-creatinine ratio progressed to 5.9 and serum albumin fell to 2.7 g/dL. His urine remained red colored, and a microscopic examination with RBC > 500 and WBC up to 10 on a high powered field. His workup was negative for antinuclear antibodies, antineutrophil cytoplasmic antibody, antistreptolysin-O (ASO) and anti-DNase B. Serum C3 was low at 81 mg/dL (reference range, 90-180 mg/dL), C4 was 13.3 mg/dL (reference range, 10-40 mg/dL), and immunoglobulin G was low at 452 mg/dL (reference range 719-1475 mg/dL). A baseline audiology test revealed normal hearing.
Percutaneous renal biopsy yielded about 12 glomeruli, all exhibiting mild mesangial matrix expansion and hypercellularity (Figure 1). One glomerulus had prominent parietal epithelial cells without endocapillary hypercellularity or crescent formation. There was no interstitial fibrosis or tubular atrophy. Immunofluorescence studies showed no evidence of immune complex deposition with negative staining for immunoglobulin heavy and light chains, C3 and C1q. Staining for α 2 and α 5 units of collagen was normal. Electron microscopy showed patchy areas of severe basement membrane thinning with frequent foci of mild to moderate lamina densa splitting and associated visceral epithelial cell foot process effacement (Figure 2).
These were reported as concerning findings for possible Alport syndrome by 3 independent pathology teams. The genetic testing was submitted at a commercial laboratory to screen 17 mutations, including COL4A3, COL4A4, and COL4A5. Results showed the presence of a heterozygous VUS in the COL4A4 gene (c.1055C > T; p.Pro352Leu; dbSNP ID: rs371717486; PolyPhen-2: Probably Damaging; SIFT: Deleterious) as well as the presence of a heterozygous VUS in TRPC6 gene (c2463A>T; p.Lys821Asn; dbSNP ID: rs199948731; PolyPhen-2: Benign; SIFT: Tolerated). Further genetic investigation by whole exome sequencing on approximately 20,000 genes through MNG Laboratories showed a new heterozygous VUS in the OSGEP gene [c.328T>C; p.Cys110Arg]. Additional studies ruled out mitochondrial disease, CoQ10 deficiency, and metabolic disorders upon normal findings for mitochondrial DNA, urine amino acids, plasma acylcarnitine profile, orotic acid, ammonia, and homocysteine levels.
Figure 3 summarizes the patient’s treatment response during 170 weeks of follow-up (Fall 2019 to Summer 2023). The patient was started on enalapril 0.6 mg/kg daily at week 3, which continued throughout treatment. Following a rheumatology consult at week 30, the patient was started on prednisolone 3 mg/mL to assess the role of inflammation through the treatment response. An initial dose of 2 mg/kg daily (9 mL) for 1 month was followed by every other day treatment that was tapered off by week 48. To control mild but noticeably increasing proteinuria in the interim, subcutaneous anakinra 50 mg (3 mg/kg daily) was added as a steroid
