Acute tubular injury or necrosis is evident. Bowman's space appears widened. But I don't know what it means. Is there ureteral obstruction? This is a challenging case.

 输尿管和肾动脉都正常，我也不太清楚肾为什么会破裂，看起来没有排斥和肾脏也没有肿大

 再发几张图片

 I agree that there is no obvious cellular rejection. The white cell margination in vessels could be secondary change. The tubular necrosis/injury is not proportional to the cellular infiltration. As you mentioned that C4d is focally positive, what about patient's donor specific antibody (DSA)? If DSA is positive, acute antibody-mediated rejection is the differential diagnosis.

The acute tubular necrosis/injury and collapse of glomeruli also suggest ischemia. I had one allograft kidney removed due to dissecting aneurysm at the anastomosis site. Please check renal artery and renal vein (for renal vein thrombosis).