Microarray predictor of response to infliximab in rheumatoid arthritis (RA) patients

We sought to find a gene-expression multigene predictor of response to infliximab therapy in Rheumatoid Arthritis patients. Using internal and external cross-validation systems we have built and validated an 8-gene predictor for response to infliximab. Blood RNA from 48 Rheumatoid Arthritis patients was extracted at baseline of anti-TNF alpha treatment with infliximab. From these 44 reached week 14 of treatment at which the clinical response was determined. Using 2/3 of the sample we built a multigene predictor using kNearest-Neighbour algorithm and Leave-One Out cross validation. The remaining 1/3 of the sample was used to estimate the precision accuracy of the predictor model.