Relationship between Low and High Anti-acetylcholine Receptor Antibody Titers and Clinical Severity in Myasthenia Gravis.

OBJECTIVE

To determine the frequency of low and high anti-AChR (acetylcholine receptor) antibody titers and to evaluate their relationship with clinical severity in myasthenia gravis.

STUDY DESIGN

Cross-sectional, observational study.

PLACE AND DURATION OF STUDY

Department of Neurology, King Edward Medical University/Mayo Hospital, Lahore from April 2017 to March 2018.

METHODOLOGY

Fifty-six seropositive patients, aged between 18-75 years, were included. A blood sample was obtained from each patient to assess for the anti-AChR antibody titers by enzyme-linked immunosorbent assay (ELISA) technique and classified as low (0.4-<50 nmol/L) and high AChR antibody titers (>50 nmol/L). Clinical severity was graded according to the Osserman's classification.

RESULTS

Out of 56 patients, 51.79% (n=29) were males and 48.21% (n=27) were females, and mean age was 32.73 +8.48 years. Mean anti-AChR antibody titer was found 40.45 + 13.54; 60.71% (n=34) had low and 39.29% (n=22) had high titers. Upon grading the severity, 1.79% (n=1) had grade I, 25% (n=14) had grade IIa, 26.79% (n=15) had grade IIb, 37.5% (n=21) had grade III, and 8.93% (n=5) had grade IV. These grades were significantly associated with high/low titers of anti-AChR antibody (p<0.001) but no significant association was found with age and gender (p=0.39 and 0.19 respectively).

CONCLUSION

Serum concentration of anti-AChR antibodies has significant association with the clinical severity in myasthenia gravis. Key Words: Anti-acetylcholine receptor antibody, Myasthenia gravis, Neuromuscular junction diseases.