Analysis of Lymphocyte Proliferation Data: Do Different Approaches Yield the Same Results?

We addressed whether different approaches to the treatment of lymphocyte proliferation data influence the interpretation of results. We focused on two specific issues: (1) the impact of using optimal concentrations of mitogen versus a repeated measures approach using all concentrations and (2) the impact of correcting for unstimulated wells, and the method chosen for doing so. First, analysis of only the optimal concentration yields the same results as using a repeated measures approach. Second, uncorrected stimulated data, difference scores, and statistical control of unstimulated values all yield identical conclusions. The stimulation index, however, frequently yields different outcomes than the other approaches. We discuss reasons for these differences, note that the equivalence between repeated measures and optimal concentration techniques is limited to studies predicting suppression of proliferation irrespective of concentration, and suggest situations when the various approaches to analysis be used.