A structural equation model was performed illustrating the relationships between various clinical and laboratory parameters—age at onset, disease duration, CSF protein, EDSS, presence of OCB, IgG index, Qalb, occurrence of relapse, number of T2-weighted white matter (WM) lesions on the initial MRI, and the presence of new T2 WM lesions on follow-up MRI—and CSF CXCL13, CCL11, and CCL20 levels in the MS group. The gene discussed is CXCL13; the disease is myeloid sarcoma.