TY - JOUR T1 - TYpe d (delta) hepatitis-reply AU - Hoofnagle JH Y1 - 1989/12/01 N1 - 10.1001/jama.1989.03430210033015 JO - JAMA SP - 2996 EP - 2996 VL - 262 IS - 21 N2 - In Reply.—  Caredda et al are correct to point out that not all cases of acute HDV coinfection and superinfection will test positive for HBsAg. In HDV coinfection, HBsAg may have already disappeared by the time the patient is cared for. Furthermore, in HDV superinfection, HBsAg titers may fall transiently to undetectable levels. Thus, testing for antibody to HDV (anti-HDV) in HBsAg-negative patients may occasionally provide evidence of delta infection. In these situations, however, one does not know whether anti-HDV indicates recent or distant infection; more direct markers of delta replication (HDV RNA, HDV antigen, or IgM anti-HDV) would be better evidence that the acute hepatitis is caused by HDV.In this regard, recent evidence suggests that HDV does not require HBsAg for replication, but rather for entry and exit from the hepatocyte. Thus, in some cases of liver transplantation for delta hepatitis, HDV antigen or RNA in the absence SN - 0098-7484 M3 - doi: 10.1001/jama.1989.03430210033015 UR - http://dx.doi.org/10.1001/jama.1989.03430210033015 ER -