干扰素诱发自身免疫性血小板减少性紫癜

A case report and literatare review:Interferon induced autoimmune thrombocytopenic purpura

21岁女性,主因"乙肝表面抗原阳性15年余,牙龈出血1周余"入院。2年前确诊为e抗原(HBe Ag)阳性慢性乙型肝炎,予干扰素联合核苷(酸)类似物拉米夫定(LAM)长期抗病毒治疗。治疗过程中定期监测,无明显不良反应。治疗第20个月获HBe Ag血清学转换,表面抗原(HBs Ag)滴度进行性下降。1周前血小板骤然下降至8×109/L。血小板严重下降的原因考虑为自身免疫性血小板减少性紫癜(AITP),依据为:1聚乙二醇干扰素α-2a相对LAM容易引起血象改变;2抗血小板抗体阳性、抗核抗体滴度急剧上升,抗SSA抗体(+),而以往为阴性;3骨髓穿刺结果考虑AITP可能性大;4其他(如肿瘤、非甾体类药物等)病因引起的血小板减少可被排除;5血栓性血小板减少性紫癜可除外;6应用糖皮质激素和丙种球蛋白效果好。提示在干扰素治疗的全程中均应密切注意血常规的变化。出现血小板严重减少者,应先甄别病因,对症处理。

A 21-year-old female patient was admitted in the hospital because of ingival bleeding for more than one week,who had HBsAg positive for more than 15 years. The patient was diagnosed as chronic hepatitis B with positive HBeAg, and was treated with Peg-IFNα-2a and LAM 2 years ago. In the regularly monitor during the treatment, she re- sponded well to the treatment with no obviously adverse effects. However, her platelet count dropped to 8~10^9/L one week before admission. The cause of severe platelet decline was considered as autoimmune thrombocytopenic purpura （AITP）, which was based on the followings： ①Peg-IFNα-2a was much easier to cause platelet dropping compared with LAM. ② The platelet antibody was positive, and the titer of anti nuclear antibody rised sharply, positive SSA antibody were observed, which were negative in the previous tests. ③ The results of bone marrow aspiration showed AITP was the most likely cause. ④ Other causes such as tumor, non-steroidal anti-inflammatory drug could be excluded.⑤Thrombotic thrombocytopenic purpura could be excluded. ⑥Immunoglobulin and glucocorticoid were effective. Therefore, blood routine test should be closely monitored during IFN treatment. In addition, it is not safe to transfuse platelets to the patient when thrombotic thrombocytopenic purpura is suspected. It is the most important to identify the etiology.