Epidemiology

Immunoglobulin preparations contain adequate hepatitis A virus antibodies

Last Updated: 2010-01-18 12:00:12 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Although the seroprevalence of hepatitis A virus (HAV) is waning in Europe and the US, human plasma pools still contain enough HAV antibodies to ensure that immunoglobulin preparations will protect patients with primary immune deficiency, researchers say.

The study, which appears in the January Journal of Allergy and Clinical Immunology, was done by researchers from Baxter BioScience in Vienna, Austria.

Little is known about the impact of declining hepatitis A incidence or the introduction of HAV vaccines on HAV antibody abundance and reactivity in intravenous immunoglobulin (IVIG) preparations, the authors explain.

Lead author Dr. Maria R. Farcet and colleagues evaluated the quantity and functionality of HAV antibodies in European and US-sourced human plasma pools and the IVIG preparations made from them.

The average HAV antibody content was higher in the 1310 European plasma pools sourced from 2003 to 2008 (1.70 IU/mL) than in the 2643 US plasma pools (0.82 IU/mL), the authors report, and antibody content declined 28% in European plasma pools and 41% in US plasma pools between 2003 and 2008.

Mean HAV antibody content was also higher in IVIG final containers manufactured from 2005 to 2007 from European sources (22.91 IU/mL) than from US sources (14.60 IU/mL).

"Although the HAV antibody content was significantly lower in US-sourced IVIG, the average US HAV antibody titer of 14.60 IU/mL appears to be adequate for clinical applications, considering that levels of 10 mIU/mL or greater HAV antibody in immunoglobulin preparations are thought to be protective," the researchers say.

HAV microneutralization titers were higher in European-derived IVIG lots (mean, 2477) than in US-derived IVIG lots (mean, 844), and there was a significant correlation between ELISA-determined HAV antibody titers and HAV microneutralization titers.

"Our results add further evidence to a decrease of HAV incidence in the US and the European union," the authors conclude. "Most importantly, though, we showed that although HAV incidence continues to decrease, HAV antibody titers in IVIG remain at protective levels and therefore appear adequate for antibody replacement therapy in patients with primary immune deficiencies."

J Allergy Clin Immunol 2010;125:198-202.