Low IgG Levels Linked to Severe Flu

Australian researchers specializing in infectious diseases found that pregnant women who became severely ill with the H1N1 flu had low levels of IgG to help fight off the virus and help the body respond to vaccine. On the other hand, moderately ill pregnant women were much less likely to have significantly suppressed levels of the antibody.

The researchers tested patients for antibody levels and found that patients who needed ICU were IgG2 deficient. Severe cases had IgG2 levels that were about one-third of those detected in people who were moderately ill. Three of four critically ill patients treated with immune globulin survived. While the testing was performed only in pregnant women, the scientists believe that the deficiency might explain why a small subset of swine flu cases become gravely ill, while most people suffer through only a bout of the flu. The study was conducted at Austin Health, a network of three hospitals in Melbourne, and because the testing involved a small number of people, further study is needed.