CXCR5 and post-transplant lymphoproliferative disease: Most notably, CXCR5+ Naive CD4 T cells were positively associated with the “Musculoskeletal Pain” factor in the PTLD cohort (rho = 0.21, Padj= 0.041), but negatively associated with this factor in healthy control data (rho = -0.56, Padj = 0.017, Figure 4D). Multiple PLQS factors were also associated with NK cell frequencies.