患儿，男，7岁，因反复发作血尿5年入院。既往有支气管哮喘史。其父亲及姑姑在学龄儿童时患过急性肾炎，母亲9年前患过肾盂肾炎均已治愈。体检：BP正常，发育营养欠佳，精神好，咽充血，扁桃体Ⅱ。肿大，心肺无异常，腹平较，肝脾未触及，肾区无叩痛。实验室检查：尿红细胞（＋ Children, male, 7 years old, due to recurrent hematuria admitted for 5 years. Past history of bronchial asthma. His father and aunt had had acute nephritis when they were school-age children and their mother had been cured of pyelonephritis 9 years ago. Physical examination: BP normal, poorly developed nutrition, good spirit, pharyngeal congestion, tonsil Ⅱ. Swollen, no abnormal heart and lung, abdominal flat, liver and spleen not touched, no percussion pain in the kidney area. Laboratory tests: urinary red blood cells (+