Abstract:

ABSTRACT Objective: To compare the clinico-pathological characteristics and prognosis in patients with different types of TMA by proven renal biopsy. Methodology: Ninty seven patients who diagnozed as TMA by renal biopsy were enrolled into this retrospective study. They included atypical hemolytic uremic syndrome (aHUS) (n=38), lupus nephritis-associated TMA (LN-TMA) (n=37), and pregnancy-associated TMA (P-TMA) (n=22). Their clinico-pathological characteristics and the prognoses were compared. Results: The patients with aHUS presented a highest level of serum creatinine 791 (397~1148) μmol/L vs. LN-TMA 388 (189~582) μmol/L vs. P-TMA 69.8 (53.9~557) μmol/L)，and a highest incidence of anemia (100% vs. LN-TMA 97.3% vs. P-TMA 63.6%), with a wide variety of TMA lesions. The patients with P-TMA presented the lowest level of systemic involvement, the lowest incidences of renal insufficiency (aHUS 100% vs. LN-TMA 89.2% vs. P-TMA 50.0%), anemia and thrombocytopenia (aHUS 76.3% vs. LN-TMA 75.7% vs. P-TMA 27.3%), and the highest incidence glomerular basement membrane (GBM) reduplication (aHUS 55.3% vs. LN-TMA 45.9% vs. P-TMA 95.5%). However, the patients with LN-TMA presented the highest level of proteinuria (aHUS 1.38 (0.74~2.58)g/24h vs. LN-TMA 2.65 (1.87~5.33) g/24h vs. P-TMA 1.18 (0.68~1.64) g/24h), the highest incidence of microscopic hematuria (aHUS 65.8% vs. LN-TMA 89.2% vs. P-TMA 50.0%), and arterial and glomerular thrombi dominantly (aHUS 57.9% vs. LN-TMA 83.8% vs. P-TMA 22.7%; aHUS 26.3% vs. LN-TMA 59.5% vs. P-TMA 4.5%， respectively). At the end of follow-up, aHUS patients showed the poorest renal outcomes to end-stage renal disease (aHUS 63.2% vs. LN-TMA 24.3% vs. P-TMA 18.2%, P<0.001), whereas LN-TMA patients had the highest incidence of recovery of renal insufficiency (aHUS 15.8% vs. LN-TMA 27.0% vs. P-TMA 18.2%, P<0.001). The percentage of tubular atrophy/interstitial fibrosis (TAIF) independently influenced the renal survival. The presence of arteriolar /arterial intimal fibroplasia, the increased percentages of glomerulosclerosis and TAIF were risk factors for non-recovering from renal insufficiency. Conclusions: The patients with different types of TMA presented a wide variety of clinico-pathological characteristics and prognoses. In these three groups, patients with aHUS had the worst prognoses, whereas patients with LN-TMA and P-TMA had better prognoses.

Key words: thrombotic microangiopathy, atypical hemolytic uremic syndrome, lupus nephritis, pregnancy, renal biopsy, prognosis