Natalizumab is an effective monoclonal antibody therapy for the treatment of relapsing- remittingmultiple sclerosis(RRMS) and interferes with immune cell migration into the central nervous system by blocking the α(4) subunit of very-late activation antigen-4 (VLA-4). Although well tolerated and very effective, some patients still suffer from relapses in spite of natalizumab therapy or from unwanted side effects like progressive multifocal leukoencephalopathy (PML).
Summing up, this pilot study shows that flow cytometry is a useful method to monitor natalizumab binding to lymphocytes from RRMS patients under therapy. Investigating natalizumab binding provides an opportunity to evaluate the molecular level of effectiveness of natalizumab therapy in individual patients. In combination with natalizumab saturation experiments, it possibly even provides a means of studying the feasability of patient-tailored infusion intervals. A routine-qualified biomarker on the basis of individual natalizumab saturation on lymphocyte subsets might be an effective tool to improve treatment safety.
Tysabri(antibody against alpha 4 integrin) works because it binds to and blocks the action of a marker on white blood cells. If you have effective blockage, you will not be able to add more antibody in a test tube and get more binding, because the binding is saturated, if you follow this you could work of if you should give more because the tysabri binding is no longer saturated