RT Journal
A1 Caredda F, Antinori S, Moroni M
T1 TYpe d (delta) hepatitis
JF JAMA
JO JAMA
YR 1989
FD December 1
VO 262
IS 21
SP 2995
OP 2996
DO 10.1001/jama.1989.03430210033013
UL http://dx.doi.org/10.1001/jama.1989.03430210033013
AB To the Editor.— 
    Dr Hoofnagle1 recently presented in JAMA an excellent comprehensive review of the field of type D (delta) hepatitis. However, we believe that some new findings deserve consideration. The author states that "delta hepatitis occurs only in patients who have HBsAg [hepatitis B surface antigen] in serum" and that "the clinician should consider testing for anti-HDV [antibody to hepatitis delta virus] in any patient with acute or chronic hepatitis who is tested HBsAg positive." This statement is suggested by the fact that HDV is a defective virus unable to replicate without the concomitant hepatitis B virus infection and apparently was confirmed by the negative results obtained in patients with acute HBsAg-negative hepatitis.2 Nevertheless, the interference of HDV infection on hepatitis B virus replication is a well-known phenomenon, and a few case reports have shown that HDV can be expressed in the absence of detectable HBsAg in