Considering vaccine non-responders (both IgG/IgM and S(ELISPot)-negative), the factors that were associated with an absence of response at univariable analysis were diabetes (OR [95%CI] 3.41 [1.41–8.22], p = 0.006), receiving ATG during the last year (OR [95%CI] 10.07 [2.64–38.31], p = 0.001), lymphopenia (OR [95%CI] 3.82 [1.64–8.89], p = 0.001), time from transplant <1 year (OR [95%CI] 3.51 [1.52–8.08], p = 0.003) and eGFR < 30 mL/min/1.73 m2 (OR [95%CI] 4.95 [1.48–16.46], p = 0.009). The gene discussed is CD40LG; the disease is diabetes mellitus.