Scientists from University of California claim to have identified a potential therapeutic target for autoimmune diseases.
They have discovered an abnormality in a patient's immune system that may lead to safer therapies for autoimmune diseases such as rheumatoid arthritis and colitis, as well as potential new ways to treat transplant rejection.
While studying a woman patient with frequent infections in the ears, urinary tract and lungs, the researchers identified antibodies from the immune system that prevent infection-fighting T cells from moving through her blood stream and entering her body's organs to attack invaders such as bacteria or viruses.
Autoimmunity occurs when the body perceives its own cells or tissue as foreign organisms and creates an immune response to itself and the majority of the sufferers are women.
"This is the first selective antibody of its type discovered in a patient," said lead study author Edward J. Goetzl, MD, UCSF professor of medicine and immunology.
"Antibodies that react more generally against blood cells, such as T cells, previously have been identified. However, this is the first to block a specific aspect of T-cell function.
"Our study offers a potential new approach to developing safer, more targeted therapies based on human antibodies," he added.
The woman involved in the study had low number of blood T cells.
The studies revealed that the patient's CD4 T cells did not move out of her lymph nodes as they would in a normal immune system because her body created antibodies to one type of sphingosine 1-phosphate (S1P) receptor.
The patient's antibodies blocked the signalling that triggers T-cell movement from the thymus and lymph nodes into blood and then into many organs.
The researchers then explored whether the woman's antibodies effectively could inhibit an autoimmune response in mice.
Antibodies against the S1P receptor, created from the patient's antibody-producing cells, were injected into mice that were induced to develop colitis.
The result was a significant reduction in severity of their diseases, including colitis-associated weight loss, in those mice compared to mice that did not receive the antibodies.
"These results have broad biological implications, since the cells that carry out our immune responses are present in every organ," said Goetzl, director of UCSF Allergy and Immunology Research.
The study appears in online edition of "The FASEB Journal," the official journal of the Federation of American Societies for Experimental Biology.