Three rheumatologists were recently awarded the 2013 Crafoord Prize in Sweden, a prize of 4 million kronor ($614,000), for discovering a risk gene linking smoking and rheumatoid arthritis. The Crafoord Prize was established in 1980 by Holger Crafoord, inventor of the artificial kidney, and his wife, Anna Greta Crafoord, and is administered by the Royal Swedish Academy of Sciences. It was established to promote and reward fundamental research in scientific fields that were left out of the Nobel Prize. These fields are mathematics, earth sciences, biological sciences, and astronomy. Only one prize is awarded each year. This unique DNA sequence discovered by these three rheumatoid arthritis scientists can greatly increase the risk of rheumatoid arthritis in humans once it is affected by smoking. Back in the 1980s, Peter Gregersen and Robert Winchester began testing for differences between human leukocyte antigen genes. Current research knows that these leukocyte antigen genes are strongly associated with autoimmune diseases. The theory states that these risk genes are supposed to increase the risk of rheumatoid arthritis by controlling the production of human leukocyte antigen (HLA). These HLAs form a pocket structure on the surface of cells, a structure that can trap some molecules (such as viruses) inside. And the body’s immune cells remove unhealthy cells by detecting these pocket structures. The unique pocket structure of some HLAs on the cell surface causes immune cells to misidentify and remove normal cells, which leads to rheumatoid arthritis. They found that a sequence containing five amino acids shared among HLA gene variants had an increased risk of rheumatoid arthritis. Lars Klareskog’s team found a 20- to 40-fold increase in the risk of rheumatoid arthritis in the Nordic population that contained the sequence and smoked, compared with a 4-fold increase in the risk in those who contained the sequence but did not smoke. Based on these findings, the scientists believe that the majority of rheumatoid arthritis development originates in the lungs. They believe that anti-citrulline proteins are involved. The findings could help treat rheumatoid arthritis more precisely.