Mackler B F, Schur P, Waldrop T, Coker E, Rossen R
J Dent Res. 1979 Jul;58(7):1701-4. doi: 10.1177/00220345790580070901.
No quantitative changes in serum IgG subclass concentrations could be correlated clinically with periodontal disease, despite evidence of restrictive IgG sublcass antibody responses in inflamed gingiva. Serum from periodontal patients also lacked circulating immune complexes.