By mixed linear regression, glycosylation values were compared between individuals with RA and controls (healthy = 0, RA = 1; adjusted for pregnancy) (Table S5 in Supplementary Material). For immunoglobulin type glycosylation, we observed in RA a lower galactosylation (A2FS0G, βA2FS0G = −0.44 ± 0.07), higher bisection (A2FS0B, βA2FS0B = 0.55 ± 0.08), and a higher sialylation per galactose (A2FGS, βA2FGS = 0.75 ± 0.08). In addition, differences were found in several non-fucosylated diantennary traits (higher A2F0G, A2F0GS, and A2GE, lower A2F0B, A2F), all mainly driven by elevated levels of H5N4E2 (βH5N4E2 = 0.97 ± 0.07) in RA patient serum. For tri- and tetraantennary N-glycosylation, we observe with RA a higher fucosylation (e.g., A3F, βA3F = 0.34 ± 0.08; A4F, βA4F = 0.56 ± 0.08) particularly within species with α2,3-linked sialylation (A3LF, βA3LF = 0.35 ± 0.08; A4LF, βA4LF = 0.58 ± 0.08), suggesting an increase in sialyl-Lewis X/A.