Clinical Pathology Of Lupus Nephritis With Thrombotic Microangiopathy

BackgroundSystemic lupus erythematosus is a common autoimmune disease and almost all the patients have renal involvement. Lupus nephritis is an important prognostic factor. The currently used classification of lupus nephritis is based on the pathological changes of glomeruli. But recent researches have found that renal vascular lesion is also very common in lupus nephritis. Thrombotic microangiopathy (TMA) is the most sever type and has the poorest prognosis. But few largescale quantitative researches of TMA have been published in our country.ObjectiveTo figure out the character, classification and prognosis of TMA associated with lupus nephritis. To investigate the significance of renal vascular lesions in lupus patients with acute renal failure.MethodsCase selection:the patients undergoing renal biopsy in PUMCH between Jan2000and Feb2009, with intact clinical and pathological data. Groups:(1)Lupus nephritis associated with TMA(n=62), proliferative lupus nephritis without vascular lesion(n=119);(2) Lupus nephritis associated with TMA is further divided into poly-immunocomplex deposit group(n=35) and oligo-immunocomplex deposit group(n=25);(3)SLE associated with ARF is mainly divided into vascular lesion group(n=20) and proliferative lupus nephritis-only group(n=16). The clinicopathological features and renal survival were retrospectively analyzed. Martius acid fuchsin brilliant blue stain was processed to identify thrombi in TMA.Results(1)TMA incidence in lupus nephritis is9.2%(n=62). TMA, which characterized by sever hypertension, prominently elevated serum creatinine, anemia and thrombocytopenia, shows the most sever manifestation and poorest prognosis in all the vascular lesion types. Mortality rate is13.6%. The incidence of death/end stage renal disease is25.0%.(2)TMA associated with lupus nephritis could further be divided into2subtypes based on the immunocomplex deposit observed in renal pathology. They are "poly-immunocomplex deposit subtype" and "oligo-immunocomplex deposit subtype". Poly-immunocomplex deposit subtype seems to be more active both in clinical and pathological manifestations. It also shows a more encouraging response to the steroid and immunosuppressant therapy than oligo-immunocomplex deposit subtype. The latter contributes to a high death/ESRD ratio.(3)The pathological reasons for acute renal failure in lupus patients are vascular lesion(43.5%), lupus nephritis-only(34.8%), crescentic glomerulonephritis(10.9%), crescentic glomerulonephritis associated with vascular lesion(6.5%), acute tubular necrosis(4.3%) in order. The former two are very similar in clinical features. But vacular lesion induced ARF shows a much poorer prognosis.ConclusionsWith the most sever manifestation and poorest prognosis, TMA is not rare in lupus nephritis. TMA associated with lupus nephritis may be divided into poly-immunocomplex deposit subtype and oligo-immunocomplex deposit subtype. This classification may be helpful in disease prognosis for the latter shows little response to steroid-immunosuppressant therapy. The most common pathological reasons for ARF in lupus patients are vascular lesion and sever proliferative lupus nephritis. Vascular lesion induced ARF has a much poorer prognosis.