患者，男性，发热38.5℃，全身有小出血点，头晕，乏力，经医院检查：血红蛋白80g/L，红细胞3×10<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20221202/13384530_0.gif">/L，白细胞3×10<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20221202/13384530_0_1.gif">/L，血小板70×10<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20221202/13384530_0_2.gif">/L，确诊为再生障碍性贫血。其发热的主要原因是