Objective    To investigate the conjugated effects of valsartan and prazosin on the patients with diabetic nephropathy and refractory hypertension

who were positive for AT

1

receptor and α

1

-adrenergic receptor antibodies.     Methods    The epitopes of

the second extracellular loop of α

1

receptor and AT

1

receptor were synthesized and used respectively to screen sera autoantibodies from 277 subjects by ELISA

including diabetic nephropathy complicated with refractory hypertension (group A

n=120)

diabetic nephropathy with non-refractory hypertension group (group B

n=111) and control group (group C

n=46). Group A was divided to group A

1

(both positive for autoantibodies against AT

1

receptor and α

1

receptor

n=71) and group A

2

(both negative for autoantibodies against AT

1

receptor and α

1

receptor

n=49)

who were given the following drugs respectively: valsartan 80 mg

po

qd; prazosin 1 mg

po

tid; aspirin 100 mg

po

qd; nitrendipine 10 mg

po

tid; hydrochlorothiazide 12.5 mg

po

qd

for 6 weeks. The blood pressure was measured before and after treatment.     Results    The positive rates of autoantibodies against α

1

receptor and AT

1

receptor in group A were 55.8% and 59.2%

higher than those in group B (27.9%

35.1%) and group C (7.5%

10.0%) (P0.01). In group A

the total effective rate of hypertension improvement of group A

1

was 87.3%

higher than that of group A

2

(49.0%) (P0.05). The clinical effectiveness of group A

1

was also better than group A

2

(P0.05).     Conclusion    The findings suggest that the autoantibodies against α

1

receptor and AT

1

receptor may play important roles in the pathogenesis of diabetic nephropathy and refractory hypertension. Valsartan and prazosin are effective and safe in the treatment of diabetic nephropathy complicated with refractory hypertension.