Immunoglobulins are proteins produced by plasma cells, a type of white blood cells and are an important part of your defense system. There are 5 types of immunoglobulins namely IgG, IgM, IgA, IgE & IgD. Immunoglobulin IgE is also present in small quantities in the blood and plays a role in allergies & parasitic infections. High IgE levels are seen in asthma, allergic bronchitis, sinusitis, hay fever & allergic skin infections.