In particular, we observed that TACI expression >20% and a high CD11c (>70%) were mutually exclusive events (P = 0.008), while patients with monoclonal gammopathy have higher TACI expression on malignant B cells compared to patients without monoclonal M-component (mean ± SD: 26.2 ± 17.3 versus 12.6 ± 14.7, P = 0.020; confirmed also by ROC curve analysis: AUC = 0.765, 95% CI: 0.626–0.964). Here, ITGAX is linked to monoclonal gammopathy.