Detection and clinical significance of serum autoantibodies in patients with myasthenia gravis

Abstract

Objective To investigate the expressions and clinical significance of serum anti - acetylcholine receptor antibodies (AChR-Ab), anti-Titin antibodies (Titin-Ab), and anti-Ryanodine receptor antibodies (RyR-Ab) in patients with myasthenia gravis (MG). Methods Serum AChR-Ab, Titin-Ab and RyR-Ab were detected with enzyme-linked immunosorbent assay (ELISA) in 182 MG patients, 105 patients of other neurological diseases (OND) and 62 normal controls. Results Serum AChR-Ab, Titin-Ab and RyR-Ab were detected positive respectively in 68.13% (124/182), 64.29% (117/182) and 67.03% (122/182) of patients in MG group. The positive rates of those antibodies in MG group were significantly higher than those in OND group ( P = 0.000, for all) and control group ( P = 0.000, for all). When 3 antibodies coexisted, the sensitivity in the diagnosis of MG was 41.21%, with 99.40% of specificity. There was no significant difference in the positive rate of serum AChR-Ab, Titin-Ab and RyR-Ab between early-onset MG subgroup and late-onset MG subgroup ( P > 0.05, for all). The positive rates of AChR-Ab were significantly higher in MG patients with thymoma than in those without thymoma ( P = 0.004). There was no significant difference in the positive rate of Titin-Ab and RyR-Ab between MG with thymoma subgroup and MG without thymoma subgroup ( P > 0.05, for all). The prevalence of AChR-Ab in generalized MG (GMG) atients (Ⅱa and Ⅱb) was higher than those in ocular MG (OMG) patients (typeⅠ; P = 0.005, 0.012). There was no significant difference in the positive rate of Titin-Ab and RyR-Ab between GMG subgroup and OMG subgroup ( P > 0.05, for all). Conclusions Serum AChR-Ab, Titin-Ab and RyR-Ab can be used as ndicators of the diagnosis of MG. Patients with 3 coexisted positive antibodies are highly suspected as MG. Higher AChR-Ab level in serum of OMG patients indicates the possibility of progressing to GMG. DOI: 10.3969/j.issn.1672-6731.2016.10.007