IODICALS

SCIENCE & TECHNOLOGY
These signposts are human leukocyte antigens (HLA)-protein
molecules that float in the cell membrane and trigger a rejection re-
sponse to foreign substances, such as organ transplant~. The antigens
also signal the presence of genes that make a person susceptible to
certain diseases. Scientists have found eight kinds of antigens that are
associated-singly or in combination-with more than 40 afflictions
ranging from rheumatoid arthritis to juvenile diabetes.
The H...