In primary immune thrombocytopenia (ITP) patients, the relationship between prior hepatitis B virus (HBV) exposure [hepatitis B surface antigen (HBsAg) negative, hepatitis B core antibody (anti-HBc/HBcAb) positive] and illness severity and treatment choice was unknown. For a study, researchers looked at data from 725 ITP patients to see if there was a link between anti-HBc serological status and illness severity. The results of a published prospective study [high-dose dexamethasone (HD-DXM), HD-DXM plus recombinant human thrombopoietin, NCT01734044] and two retrospective studies (standard-dose and low-dose rituximab) were rearranged to assess the impact of anti-HBc serological status on the response and outcome to ITP-specific treatments, as well as the risk of HBV reactive in ITP patients, the prevalence of HBsAg-HBcAb+ and HBsAg-HBcAb- was 51.03% and 48.97%, respectively. 

Patients in the HBsAg-HBcAb+ group had a lower platelet count, a higher bleeding score, and stayed in the hospital longer than those in the HBsAg-HBcAb- group (P=0.002, 0.033, and 0.008, respectively). In addition, the initial full response rate of HBsAg-HBcAb+ patients was lower than that of HBsAg-HBcAb+ patients (452% vs. 598%) (P=0027). Finally, in ITP patients, past HBV exposure was linked to illness severity and hospitalization. Positive anti-HBc antibodies may be a predictor of poor response to ITP-specific therapies.