DIAGNOSTIC ANALYSIS OF
THIN BASEMENT MEMBRANE NEPHRITIS USTING THE ELECTRON MICROSCOPE
Liu Jingcheng, Xiao Lihong,
Liu Hong,Yang Jiyun
Department of pediatrics,
First Hospital Beijing University, Beijing, China
Objective: To use the electron
microscope in the diagnostic analysis of results obtained from renal biopsy
specimens showing diffuse thining of the glomerular basement membrane
(thickness<250nm)
Methods: 19 renal biopsy specimens with negative immunofluoresence
results,and showing only minismal pathological-changes under the light
microscope were investigated using the electron microscope.All specimens
observed showed diffused thining of the glomerular basement membrane
(<250nm).Indirect immunofluoreseme technique was employed to investigate
the expression of cutaneous glomerular basement membrane ¦Á 1 (TV) and ¦Á 5 (TV) chains in skin biopsies of 7
casses that had a positive family history (mathernal) of microscopic
hematuria
Results: (1) Two of the 19 cases investigated showed negative skin biopsy
result confirming the diagnosis of alport syndrome (AS). (2) A specimen
that had first been examined using the electron microscope and later
subjected to immunohistochemical studies because the slid cover had slipped
off was discovered to be a thin basement membrane nephropathy complicated
by IgA nephropathy. (3) Electron dense materical deposits was observed in
the mesangium in 6 cases observed, together with the clinical
manifestations of these patients. Thin basement membrain nephropathy
complicated by glomerulenephritis was considered a biagnosis. (4) No
granular deposits was observed along the glomerular basement membrane in
the 17 cases of TBMN whereas this was obsered in the 2 cases with alport
syndrome
Conclusion: When using the electron
microscope to diagnose TBMN, caution should be exercised to rule out alport
syndrome and also the possibility of IgA nephropathy or glomerulnephritis
complicating TBMN. Granular deposits along the glomerular basement membrane
should also lead to a suspicion of alport syndrome.