Pharmaceutical scientist Derek Lowe writes in his In the Pipeline blog about both the difficulties and ultimate rewards associated with the search for biomarkers. A potential reward is "to find a simple blood test that will give you advance news of how a slow-progressing disease is responding to treatment." However, "we have markers, but that no one can quite agree on how relevant they are (and for which patients), and other times we have nothing to work with at all." In addition, Lowe says, "A patient's antibodies might, in theory, be a good place to look for markers in many disease states, but that's some haystack to go rooting around in."
Lowe points to a new paper in Cell that presents a good starting point. The authors say that the body's own adaptive immune system is likely a rich source of protein biomarkers. But, right now, so much is not known about which antigens trigger which immune responses that diagnostically useful antibodies remain unknown. So, the authors went on a fishing expedition for biomarkers by creating a library of antigen molecules they call "peptoids."
They put them together in a microarray and tried them against serum from a rodent model of multiple sclerosis. They found several peptoids that pulled down antibodies from the model animals and not from the controls. It sounded promising, so they did the same thing with serum from real Alzheimer's patients. Three of them seemed to find antibodies for Alzheimer's.
"So while this isn't good enough for a diagnostic yet, for a blind shot into the wild blue immunological yonder, it's pretty impressive," Lowe writes.