Serum ryanodine receptor antibody on the assessment of clinical symptoms in patients with myasthenia gravis

Xiang ZHANG; Jian QIAO; Chuanzhen Lü

ABSTRACT

BACKGROUND:

Myasthenia gravis (MG) patients with thymoma were often neglected in clinical work and delayed the therapy.

OBJECTIVE:

To investigate the significance of the Ryanodine receptor (RyR) antibody on the assessment of MG.

DESIGN:

A case analysis.

SETTING:

Institute of neurology in a hospital of a university.

PARTICIPANTS:

This experiment was carried out in the Institute of Neurology, Fudan University from June 1999 to March 2002. There were 66 MG patients with thymoma(MGT group), 98 MG patients with non-thymoma (NTMG group), 50 patients with non-myasthenia gravis(NMG) and 123 normal persons (NC group).

METHODS:

Sarcoplasmic reticulum(SR) abounded in RyR was extracted with differential centrifugation, in order to establish a detecting system of ELISA-RyR-RyR antibody (RyR-ab).MAIN OUTCOME

MEASURES:

The levels of RyR-ab in serum of researched subjects.

RESULTS:

Positive rate of RyR-ab in MGT group was higher than that in NTMG and NMG groups(P ＜ 0.01), moreover, the sensitivity and the specificity were 81.8% and 94.5% respectively. The positive rates of MGT groups with different thymus histology were no significant difference(P＞ 0.05). Ages, clinical scores and levels of acetylcholine receptor antibody (AchR-ab) in patients with positive RyR-ab were higher than those in patients with negative RyR-ab( P ＜ 0.01 ) in MG group. The levels of RyR-ab was positive correlated with the severities of clinical symptoms in MG patients, especially the patients in MGT group( r = 0. 626, P ＜ 0.01) . And among the different histological types of MGT, thymoma of epithelioid cells has the highest correlation coefficient ( r = 0. 592, P ＜ 0. 01).

CONCLUSION:

The detection of RyR-ab has better sensitivity and specificity for the diagnosis of MGT and the levels of RyR-ab is positive correlatied with the severities of MG patients.