Table 1 Classification and clinical features of fibrillary and immunotactoid glomerulopathies
Fibrillary glomerulonephritis | Immunotactoid glomerulopathy | |
|---|---|---|
Composition | Fibrils | Microtubules |
Fibril or microtubule size | Average diameter 18–22 nm (usual range 12–30 nm) | Typically >30 nm (range 16–90 nm) |
Arrangement of fibrils or microtubules | Randomly arranged fibrils | Parallel arrays of microtubules |
Immunoglobulin type | Usually polyclonal (mostly IgG4 sometimes with IGg1) occasionally monoclonal (IgGκ) | Usually monoclonal IgGκ or IgGλ |
Light microscopy | Mesangial proliferation, membranoproliferative GN crescentic GN, sclerosing GN diffuse proliferative GN with endocapilliary exudation | Atypical membranous GN, diffuse proliferative GN membranoproliferative GN |
Association with lymphoproliferative disorder | Uncommon | Common (chronic lymphocytic leukaemia, nonHodgkin lymphoma) |
Renal presentation | Sub nephrotic or nephrotic range proteinuria + haematuria hypertension, rapidly progressive glomerulonephritis | Nephrotic syndrome with microhaematuria and hypertension |
Other manifestations (fibrillar deposits) | Pulmonary haemorrhage | Microtubular inclusions in leukaemic lymphocytes |
Treatment | Various immunosuppressive drugs tried with variable response (see table 1) | Treatment of the associated lymphoproliferative disorder |
Racial predilection | Predominantly Caucasian | Predominantly Caucasian |
Peak occurrence | 5th to 6th decades | Age 60 years |
Prognosis | Established renal failure in half of patients within 2–4 years | Probably better renal prognosis than fibrillary GN |
Frequency in renal biopsies | Approximately 1 % of renal biopsies | 0.06% of renal biopsies |