Every year World Health Day is celebrated on 7th April which is the day World Health Organization was born or came into existence. The World Health Day is based on a theme selected by World Health Organization and the theme of 2010 World Health Day is “Urbanization: a challenge for public health” and the World Health Day 2010 campaign is “1000 cities, 1000 lives”.

Why the theme?

The World Health Organization select a theme based on the importance of the particular subject and this year’s theme was selected to give importance to the public health problems of the cities across the globe. At present context the subject of healthy cities is very important as more than 50% of world population live in cities. In the year 2007 itself more than half of the world population started living in the cities, which is only growing and it is estimated that by 2030 more than 60% of the world population will reside in cities. Here lies the importance of urban health and so the World Health Day theme. At present more than 3 billion people live in cities.

The transfusion medicine (blood and blood product transfusion) is basically the study of antigen and antibodies to RBCs (red blood cells). The two most important factors of blood transfusion are ABO antigens and antibodies and Rh system, most important being the ABO blood group antigen system and Rh system is the second most important factor in transfusion medicine. Other factors such as transmission of infectious agents, immunologic and non immunologic reaction of blood and blood product transfusion are secondary to ABO blood group antigen system and Rh system.

What is the importance of ABO antigens and antibodies?

The ABO antigen system is the most important in blood and blood product transfusion (also called transfusion medicine) and was first recognized in the year 1900. The ABO antigens are present in the plasma and other body fluids as glycoprotein, although the ABO antigens are carbohydrates and attached to lipids glycosphingolipids or proteins (glycoprotein). H substance is the precursor on which antigen A and antigen B are attached. Addition of N-acetylgalactosamine forms antigen A and addition of galactose produces antigen B. individuals who can not form H substance due to lack of the gene form Bombay phenotype (Bombay blood group).