Posttransfusion non-A, non-B hepatitis after cardiac surgery: a prospective study

Blood transfusion and hepatitis: still a threat?

The incidence of post-transfusion hepatitis (PTH) in recipients of blood products is reviewed. PTH was observed in 10%-12% of recipients of blood products in the United States, 2%-4% in northern Europe and 15%-20% in southern Europe. All studies indicate that 80%-90% of all PTH cases are attributed to non-A/non-B. At least 40% of the patients with PTH non-A/non-B will develop chronic hepatitis or cirrhosis. No specific tests for the detection of the non-A/non-B agent(s) exist. However, several independent studies indicate that part of the donors carrying the infectious non-A/non-B agent have increased levels of alanine amino transferase (ALT). When donors are excluded with elevated ALT values, it is estimated that about 30% of the PTH non-A/non-B cases would be prevented. Some studies indicate that anti-hepatitis B core (anti-HBc) positive donors may carry an increased risk to transmit the non-A/non-B agent, but more recent studies do not confirm this. There is hope that a specific non-A/non-B test will be developed soon.

Transfusion-associated hepatitis B: past and present

Thus, it can be concluded that: (1) Hepatitis B, even before the introduction of donor screening for HBsAg, probably never accounted for more than one-quarter of all cases of transfusion-associated hepatitis. (2) As of 1988, the frequency of this viral infection in blood recipients, now that sensitive donor screening for HBsAg is routine, is less than 10%. The exception are multiply transfused populations, such as hemophiliacs, the majority of whom have evidence of current or past exposure to hepatitis B. However, new inactivation procedures are likely to reduce the attack rate in virgin populations of hemophiliacs. (3) Interdiction of paid blood has proved far more effective than donor screening for HBsAg in reducing the overall frequency of transfusion-associated hepatitis. (4) The current requirement that all donors be screened for anti-HBc and ALT as surrogate markers of non-A, non-B hepatitis infection, and for anti-HIV, is likely to reduce the hepatitis B attack rate even more, perhaps to near zero. (5) The long-term outcome of transfusion-associated hepatitis B has not been determined, a task that will remain difficult to accomplish because of the paucity of current cases. Information in this regard will need to be derived from the recall and reevaluation of pedigreed patients who participated in prospective studies that were conducted in the distant past.

Prevention of post-transfusion non-A, non-B hepatitis by non-specific immunoglobulin in heart surgery patients

To evaluate the effectiveness of immune serum globulin (ISG) in preventing non-A, non-B hepatitis, 291 heart surgery patients who received blood from voluntary donors were randomly assigned to receive either ISG or no additional protection. ISG was given intramuscularly before and 1 week after transfusion. 98 controls and 100 in the ISG group completed the study. Post-transfusion non-A, non-B hepatitis developed in 11 (11.2%) controls but in only 3 (3.0%) of the ISG group (p = 0.0203). 8 (72.7%) of control group with hepatitis had symptoms, and in 5 (45.4%) the disease became chronic. The disease was self-limiting in all 3 ISG patients affected, and only 1 of them had symptoms. Among those with non-A, non-B hepatitis aminotransferase levels were higher in the controls than in the ISG patients. Incubation periods longer than 8 weeks correlated with a tendency for the disease to become chronic. ISG recipients had shorter as well as more homogeneous incubation periods. ISG could be a safe, low-cost means for preventing post-transfusion non-A, non-B hepatitis which does not call for the discarding of donated blood.

Rationale for surrogate testing to detect non-A, non-B hepatitis

NANB hepatitis was initially recognized in 1975 and 13 years later, the exact etiology of this presumed viral disease remains uncertain. The acute illness is relatively mild with only about 25% of patients becoming icteric. Nevertheless, at least one half of the patients have evidence of chronic infection, and, as recently recognized, 10% to 20% develop severe liver disease. Because approximately 2% of patients who receive transfusions and whose underlying medical condition permits long term follow-up develop posttransfusion hepatitis, procedures for reducing this risk are considered prudent. Unfortunately specific tests for detecting NANB hepatitis are not available, and it is unlikely that such tests will be available in the near future. Hence, testing by surrogate or nonspecific tests (ALT and anti-HBc) were recommended because evidence from two studies conducted during the 1970s showed these tests identify some donors thought to transmit the infection. However, randomized, controlled prospective studies to determine whether these tests will, in fact, reduce NANB posttransfusion hepatitis were not performed. By the mid-1980s it was apparent these studies would not be performed nor were studies to determine the incidence of NANB posttransfusion hepatitis in the post-AIDS screening era likely to be initiated. Therefore, surrogate testing, as the best available method for reducing posttransfusion hepatitis, was implemented in the United States in 1986-87.

Post-transfusion non-A, non-B hepatitis after cardiac surgery. Prospective analysis of donor blood anti-HBc antibody as a predictive indicator of the occurrence of non-A, non-B hepatitis in recipients

We prospectively studied the incidence of post-transfusion non-A, non-B hepatitis in 64 cardiac surgery patients: 4 (6.25%) developed non-A, non-B hepatitis after an incubation period of 4-10 weeks. Units of blood products from donors seropositive for antibody to hepatitis B core antigen (anti-HBc) were not associated with a greater risk of non-A, non-B hepatitis in recipients than units from seronegative donors. Our data indicate that donor blood anti-HBc testing is of no value as a screening method to reduce the incidence of post-transfusion non-A, non-B hepatitis.