PITX2 and infection: Five Ig classes have been distinguished: IgMs, which are the first type of antibody that neonates can produce in case of an infection; IgGs, which appear when the organism is exposed for the second time to a particular antigen and provide protection against toxins and viruses; IgEs, which are produced after an allergic reaction and function to protect the organism against parasite infections; IgAs, which protect the organism against local infections; and IgDs, which act as receptors for B lymphocyte antigens, although their role has not been completely clarified yet[3].