الفهرس 
amyloidosis overviewOnly 14 pages are availabe for public view
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Abstract
Amyloidosis is the group of heterogeneous diseases caused by deposition of abnormally folded fibrils in extracellular space of any organ (Sipe et al., 2014).
Amyloidosis was described as early as three hundreds years ago. However, the term amyloidosis was introduced by Rudolph Virchow describing corpora amylacea of the nervous system in 1854 (Virchow, 18363).
There are 31 proteins identified so far as amyloidogenic proteins (Sipe et al., 2014). However, AL & AA are the most common types encountered in clinical practice (Said et al., 2013).
Other rare forms of amyloidosis that may affect the kidney are (in order of frequency); leukocyte chemotactic factor 2 (ALECT2) (Benson et al., 2008), fibrinogen A chain (AFib) (Benson et al., 1993), transthyretin (ATTR) (Andrade et al., 1952), Apo AI, Apo AII, or Apo AIV (AApo AI/AII/AIV) (Benson et al., 2001; Soutar at al.,1992; Sethi et al., 2012), lysozyme (ALys) (Pepys et al., 1993) and gelsolin (AGel) (Maury et al., 1993).
Tissue biopsy is mandatory for establishing the diagnosis of amyloidosis (Picken et al., 2010). Histological examination of H&E stained biopsy specimens demonstrates an amorphous, eosinophilic substance that stains pink with the Congo red, and displays unique apple-green birefringence by polarized microscopy.
Ultrastructural examination of amyloid fibrils reveals randomly arranged non branched fibrils measured 7-14 nm (Cohen & Calkins, 1959).
Typing of amyloidosis is a cornerstone in the workup of amyloidosis, it helps tailoring the management strategy and prediction of the prognosis (Gillmore et al., 2014).
Kidney is one of the most commonly involved organs in systemic amyloidosis ((Merlini & Palladini., 2012), renal amyloidosis accounts for approximately 2% of renal biopsies (Said et al., 2013).
Amyloidosis can affect any compartment in renal tissue. However, the glomerulus is the most commonly affected compartment (Casteno et al., 2015).
In this study, 118 cases of renal amyloidosis were collected from ASUS- EM lab diagnosed during the period from January 1990 to December 2015 and 19 cases were subjected to immunohistochemical typing by anti SAA, Kappa light chain & Lambda light chain antibodies.
Our results show that the patients’ ages ranged between 7-68 years with a mean age 41 years. Slight male predominance was found with male to female ratio was 1.7:1. Systemic inflammatory conditions were encountered in 32 cases (27%), 13 of them (11%) suffered from FMF.
Regarding the clinical characteristics; proteinuria was reported in 84 cases (71%), nephrotic range in 66 cases (55.9%) and subnephrotic range in 17 cases (14.4%). Raised serum creatinine was found in 47 cases (39.8%). Acute renal failure was reported in 3 cases (2.5%) and End stage renal disease(ESRD) was reported in 7 cases (5.9%). Hypertension was found in 7 cases (5.9%).
By light microscopic examination of our cases glomerular amyloid deposits were encountered in 115 cases (97.5%), which were diffuse mesangial in 96 cases (81.35%) and nodular in 19 cases (16%). Vascular amyloid deposits were found in 99 cases (83.9%). Interstitial amyloid deposits were seen in 64 cases (54.2%).
Concomitant glomerular, vascular and interstitial involvement were found in 55% of cases & mixed glomerular and vascular involvement only were found in 82.2% of cases.
In the present work, ultrastructural examination revealed randomly arranged non branching fibrils ranging in size between 7-14 nm. The major deposition site was the mesangium in 104 cases (88.1%), along with GBM deposits in 36 cases (32.5%) & isolated GBM deposits were found in 6 cases (5%).
Immunohistochemical typing revealed AA amyloidosis with positive staining for amyloid A protein in 14 cases (73.68%). Light chain AL amyloidosis was found in 5 cases (26.3%), four of them showed positive staining for lambda light chain and one case showed positive staining for kappa light chain.
Regarding the correlation between amyloid type with clinicopathologic features in our cases; Although not a statistically significant result, cases in the current study with AL amyloidosis were older (mean age 57.4 years) than those with the AA type (mean age 46.4 years; p = 0.060). Males were more commonly affected in both types (M: F ratio was1.5:1 & 2.5:1 respectively). Regardless amyloidosis type, distribution among renal compartments was the same in the present study.
This study showed that renal amyloidosis is uncommon but not a rare disease (representing 2.9% of renal biopsies). AA amyloidosis represented the commonest type of renal amyloidosis in this study (73.6%). The most common underlying diseases was systemic inflammatory diseases, on top FMF.