HSP pooled from HIV negative fertile donors compared to HSP pools from random donors showed statistically significant higher concentrations of TGF-ß1 (p = 0.0001), IL-2 (p = 0.0297), CCL3 (p = 0.0001), CCL2 (p = 0.001) and statistically significant lower concentration of IL-4 (p = 0.0008), IL-13 (p = 0.0001), TGF-ß2 (p = 0.0039), TGF-β3 (p = 0.0001), IL-1 ß (p = 0.0061), IL-1ra (p = 0.0013), CCL4 (p = 0.0002), IP-10 (p = 0.033), CXCL12 (p = 0.0001), CCL5 (p = 0.0002) and CXCL9 (p = 0.0001). The gene discussed is IL4; the disease is hereditary spastic paraplegia.