ABSTRACT
A 27-year-old man was hospitalized for acute kidney injury associated with antiglomerular basement membrane antibodies (anti-GBM). He underwent immunosuppression and plasma exchange therapy, without recovery of renal function. Later on, he was again admitted to the hospital with seizures. Evidence of microangiopathic hemolytic anemia, with schistocytes in peripheral blood, was present, as well as a persistent low platelet count and activity of von Willebrand factor from adherence to protease (ADAMTS-13) less than 1 %. The presence of IgG antibodies against ADAMTS-13 was documented, leading to a diagnosis of thrombotic thrombocytopenic purpura (TTP) in the context of Goodpasture's syndrome. The TTP was treated with rituximab and plasmapheresis with a good response. We conclude that early measurement of ADAMTS-13 activity dictated the most appropriate therapy and achieved excellent results in this patient.
Subject(s)
ADAM Proteins/deficiency , Anti-Glomerular Basement Membrane Disease/complications , Purpura, Thrombotic Thrombocytopenic/blood , ADAM Proteins/immunology , ADAMTS13 Protein , Adult , Anti-Glomerular Basement Membrane Disease/pathology , Antibodies, Monoclonal, Murine-Derived/therapeutic use , Humans , Immunoglobulin G/blood , Immunologic Factors/therapeutic use , Male , Plasmapheresis , Platelet Count , Purpura, Thrombotic Thrombocytopenic/complications , Purpura, Thrombotic Thrombocytopenic/therapy , RituximabABSTRACT
BACKGROUND: Proteinuria is a significant independent determinant of the progression of chronic renal diseases. It induces an increased synthesis of angiotensin II, endothelin and profibrogenic growth factors, such as transforming growth factor-beta (TGF-beta), by mesangial and tubular cells. The antiproteinuric effect of angiotensin-converting enzyme inhibitors (ACEIs) in diabetic and non-diabetic nephropathies predicts long-term renoprotection afforded by these drugs. Angiotensin II receptor antagonists are renoprotective in patients with type 2 diabetes, but studies about their effect in non-diabetic proteinuric nephropathies are very scarce. METHODS: We randomly assigned 97 patients with non-diabetic nephropathies and proteinuria >1.5 g/24 h to treatment with losartan (50 mg daily) or amlodipine (5 mg daily) for 20 weeks. Doses of the study medications were titrated to achieve a target blood pressure <140/90 mmHg in both groups. Primary outcome was the decrease in the level of 24 h proteinuria. Secondary outcomes were changes in the plasma and urinary levels of TGF-beta. RESULTS: The baseline characteristics in both groups were similar. Proteinuria decreased by 32.4% (95% confidence interval -38.4 to -21.8%) after 4 weeks of treatment and by 50.4% (-58.9 to -40.2%) after 20 weeks in the losartan group, whereas no significant proteinuria changes were observed in the amlodipine group (P < 0.001). There was no significant correlation between the level of baseline proteinuria and the proteinuria decrease induced by losartan. Both losartan and amlodipine induced a similar and significant blood pressure reduction. Target blood pressure was achieved with the initial dose of study medication (50 mg daily) in 76% of losartan group patients and in 68% of the amlodipine group patients (5 mg daily). Urinary TGF-beta significantly decreased with losartan (-22.4% of the baseline values after 20 weeks of treatment), whereas it tended to increase with amlodipine (between-group difference P < 0.05). A significant correlation between proteinuria decrease and urinary TGF-beta reduction was found in the losartan group (r = 0.41, P < 0.005). Serum creatinine and serum potassium remained stable during the study in both groups. CONCLUSIONS: Losartan induced a drastic decrease in proteinuria accompanied by a reduction in urinary excretion of TGF-beta in patients with non-diabetic proteinuric renal diseases.
