Your blood type is determined by the proteins found on the surface of your red blood cells. There are four main types: A, B, AB and O.
They are categorized based on the presence or absence of certain antigens on the surface of red blood cells. For example, people who have type A blood have A antigens and no B antigens; people who have type B blood have B antigens and no A antigen.
People with blood type A have the weakest immune system. The reason for this is that people with blood type A produce IgA antibodies, a type of immune globulin, in small amounts. This means they have fewer antibodies to fight infection and disease. Type A also get sick more often than other types because their bodies are more sensitive to bacteria, viruses and other germs.
People with blood type B have a moderate immune system. They make enough immunoglobulin A to fight off most infections but not as much as type A people do. This means they’re more likely to get sick than someone with type O or AB blood.
Type O people have a strong immune system and are the least susceptible to infections because their bodies produce high levels of immunoglobulin A antibodies. Their bodies also produce fewer antibodies than those of other blood types, so they’re less likely to suffer from autoimmune diseases such as lupus or rheumatoid arthritis.
