The levels of anti-CXCR3 and anti-CXCR4 abs strongly correlate with each other in HD and in SSc patients (r = 0.89 and r = 0.85, respectively; p ≤ 0.001, n = 198 and n = 312; Fig. 1). The gene discussed is CXCR4; the disease is systemic sclerosis.