CD19 and fibromyalgia: This research delineated three pivotal findings [152]: the first observation highlighted differences in monocytic cell percentages among fibromyalgia patients, especially when considering baseline conditions, the second discovery indicated a diminished percentage of CD19+ B cells in those patients with fibromyalgia, and, finally, the third finding revealed reduced stimulation indices of IFN-γ within the fibromyalgia cohort.