The remaining 34 proteins showed at least 2-fold higher expression in periodontitis, highlighting immunoglobulins (Ig) heavy constant gamma 3 (3.78), kappa light chain (2.19), and heavy variable 5-51 (2.18), plasma protease C1 inhibitor (3.61), haptoglobin (3.35), and another Hb, delta (3.26) (Table 2). Here, GSTM1 is linked to periodontitis.