Human Leucocyte Antigen B50 Is Associated with Conversion to Generalized Myasthenia Gravis in Patients with Pure Ocular Onset.
OBJECTIVE
The aim of this study was to investigate the associations between major histocompatibility complex (MHC) class I and II alleles and disease characteristics in Turkish patients with myasthenia gravis (MG).


METHODS
The MHC class I and II alleles of 108 unrelated MG patients were genotyped. The human leucocyte antigen (HLA) distribution of all MG patients and subgroups of MG patients (grouped according to disease characteristics) was compared to that of 250 healthy controls.


RESULTS
Overall distributions of HLA-B*61 and C*05 were more frequent in MG patients (7.4 vs. 2.0% and 14.8 vs. 6.8%, respectively) than in non-MG patients. Subgroup analyses revealed that HLA-DRB1*14 and DQB1*02 alleles were more frequent in early-onset MG [n = 10 (20.8%) vs. n = 25 (10.0%) and n = 21 (43.8%) vs. n = 59 (23.6%)]. In patients seropositive for anti-AchR antibodies, the frequencies of HLA-B*50 and C*05 were higher. HLA-C*05, DRB1*01, and DRB1*11 were higher in patients with ocular MG. In addition, HLA-A*01, A*31, B*08, and DRB1*14 were higher among patients with thymic hyperplasia, whereas DQB1*03 was lower. However, all of these differences lost significance after correction of the p value for multiple comparisons. No allele association was found among patients with thymoma. Strikingly, patients with generalized MG who had pure ocular symptoms at disease onset had significantly increased HLA-B*50 compared to the controls (corrected p < 0.001, OR = 9.92; 95% CI 3.05-32.22).


CONCLUSIONS
The HLA-B*50 allele was associated with conversion to generalized disease in patients with pure ocular symptoms at disease onset. This finding could extend our understanding of the complex interactions between the pathogenesis of MG and genetic heritage.
Department of Neurology, TCSB Izmir Tepecik Education and Research Hospital, Izmir, Turkey.
Bedile Irem
BI
Tiftikcioglu
Irem Fatma
IF
Uludag
Yasar
Y
Zorlu
İbrahim
İ
Pirim
Ufuk
U
Sener
Figen
F
Tokucoglu
Meltem
M
Korucuk
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D005128:Eye Diseases / Q000150:complications; D005260:Female; D005805:Genes, MHC Class I / Q000235:genetics*; D005802:Genes, MHC Class II / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006680:HLA Antigens; D059866:HLA-DQ beta-Chains / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000097:blood / Q000150:complications / Q000235:genetics*; D014421:Turkey; D055815:Young Adult
D006680:HLA Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens