Fibrillary and immunotactoid glomerulopathies are thought by some experts to be related disorders. They are found in about 0.6% of renal biopsy specimens, occur equally in men and women, and have been described in patients ≥ 10 years. Average age at diagnosis is about 45. Mechanism is unknown, although deposition of immunoglobulin, particularly IgG kappa and lambda light chains and complement (C3), suggests immune system dysfunction. Patients may have accompanying cancer, paraproteinemia, cryoglobulinemia, plasma cell dyscrasia, hepatitis C infection, or systemic lupus erythematous Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic, multisystem, inflammatory disorder of autoimmune etiology, occurring predominantly in young women. Common manifestations may include arthralgias and... read more , or they may have a primary renal disease without evidence of systemic disease. Immunotactoid glomerulonephritis in particular is commonly associated with chronic lymphocytic leukemia Chronic Lymphocytic Leukemia (CLL) Chronic lymphocytic leukemia (CLL) is characterized by progressive accumulation of phenotypically mature malignant B lymphocytes. Primary sites of disease include peripheral blood, bone marrow... read more and B cell lymphoma Overview of Lymphoma Lymphomas are a heterogeneous group of tumors arising in the reticuloendothelial and lymphatic systems. The major types are Hodgkin lymphoma Non-Hodgkin lymphoma See table Comparison of Hodgkin... read more .
All patients have proteinuria, > 60% in the nephrotic range. Microscopic hematuria is present in about 60%; hypertension Hypertension Hypertension is sustained elevation of resting systolic blood pressure (≥ 130 mm Hg), diastolic blood pressure (≥ 80 mm Hg), or both. Hypertension with no known cause (primary; formerly, essential... read more , in about 70%. Slightly > 50% have renal insufficiency at presentation.
Diagnosis is suggested by laboratory data and confirmed by renal biopsy. If nephrotic syndrome Overview of Nephrotic Syndrome Nephrotic syndrome is urinary excretion of > 3 g of protein/day due to a glomerular disorder plus edema and hypoalbuminemia. It is more common among children and has both primary and secondary... read more is present, testing is done as for other cases of nephrotic syndrome.
Urinalysis usually shows features of nephritic syndrome Overview of Nephritic Syndrome Nephritic syndrome is defined by hematuria, variable degrees of proteinuria, usually dysmorphic red blood cells (RBCs), and often RBC casts on microscopic examination of urinary sediment. Often... read more and nephrotic syndrome.
Serum C3 and C4 are usually measured and are occasionally decreased.
Light microscopy of a biopsy specimen shows mesangial expansion by amorphous eosinophilic deposits and mild mesangial hypercellularity. Various other changes may be present on light microscopy (eg, crescent formation, membranoproliferative patterns). Congo red staining is negative for amyloid. Immunostaining reveals IgG and C3 and sometimes kappa and lambda light chains in the area of the deposits.
Electron microscopy shows glomerular deposits consisting of extracellular, elongated, nonbranching microfibrils or microtubules. In fibrillary glomerulonephritis, the diameter of the microfibrils and microtubules varies from 20 to 30 nm. In immunotactoid glomerulonephritis, the diameter of the microfibrils and microtubules varies from 30 to 50 nm. In contrast, in amyloidosis, fibrils are 8 to 12 nm.
Some experts distinguish immunotactoid from fibrillary glomerulopathy by the presence of microtubular (as opposed to smaller microfibrillar) structures in the deposits; others distinguish them by the presence of a related systemic illness. For example, a lymphoproliferative disorder, monoclonal gammopathy, cryoglobulinemia, or systemic lupus erythematosus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic, multisystem, inflammatory disorder of autoimmune etiology, occurring predominantly in young women. Common manifestations may include arthralgias and... read more may suggest immunotactoid glomerulonephritis.
The conditions are usually slowly progressive with renal insufficiency, progressing to end-stage renal disease Chronic Kidney Disease Chronic kidney disease (CKD) is long-standing, progressive deterioration of renal function. Symptoms develop slowly and in advanced stages include anorexia, nausea, vomiting, stomatitis, dysgeusia... read more in 50% of patients within 2 to 4 years. A more rapid decline is predicted by the presence of hypertension Hypertension Hypertension is sustained elevation of resting systolic blood pressure (≥ 130 mm Hg), diastolic blood pressure (≥ 80 mm Hg), or both. Hypertension with no known cause (primary; formerly, essential... read more , nephrotic-range proteinuria, and renal insufficiency at presentation.
Evidence is lacking, but consider angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), immunosuppressants, and/or corticosteroids
Evidence to support specific treatments is lacking although ACE inhibitors and ARBs may be used to reduce proteinuria. Immunosuppressants have been used based on anecdotal evidence but are not a mainstay of therapy; success may be greater with corticosteroids when serum complement is decreased. The disorder may recur after transplantation.
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