Overall, the healthy controls had significantly higher frequencies of the HLA-C1 ligand (C1/C1 or C1/C2) compared to patients (72.7 vs. 60 %, p = 0.014); on the other hand, frequency of the HLA-C2 ligand (C2/C2 or C1/C2) was significantly higher in cHL patients (88.9 vs. 76 %, p = 0.003). Here, C2 is linked to classic Hodgkin lymphoma.