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Background: Acquired myasthenia gravis (MG) is a rare antibody-mediated autoimmune disease caused by impaired neuromuscular transmission, leading to abnormal muscle fatigability. The aetiology is complex, including genetic risk factors of the human leukocyte antigen (HLA) complex and unknown environmental factors. Although associations between the HLA complex and MG are well established, not all involved components of the HLA predisposition to this heterogeneous disease have been revealed. Well-powered and comprehensive HLA analyses of subgroups in MG are warranted, especially in late onset MG., Methodology/principal Findings: This case-control association study is of a large population-based Norwegian cohort of 369 MG patients and 651 healthy controls. We performed comprehensive genotyping of four classical HLA loci (HLA-A, -B, -C and -DRB1) and showed that the DRB1*15:01 allele conferred the strongest risk in late onset MG (LOMG; onset ≥ 60 years) (OR 2.38, p(c)7.4 × 10(-5)). DRB1*13:01 was found to be a protective allele for both early onset MG (EOMG) and LOMG (OR 0.31, p(c) 4.71 × 10(-4)), a finding not previously described. No significant association was found to the DRB1*07:01 allele (p(nc) = 0.18) in a subset of nonthymomatous anti-titin antibody positive LOMG as reported by others. HLA-B*08 was mapped to give the strongest contribution to EOMG, supporting previous studies., Conclusion: The results from this study provide important new information concerning the susceptibility of HLA alleles in Caucasian MG, with highlights on DRB1*15:01 as being a major risk allele in LOMG.

The Norwegian Radiation Protection Authority has performed measurements of finger doses to nuclear medicine staff exposed to 99Tc(m), researchers handling 32P, surgeons performing X-ray guided orthopaedic surgery and surgeons and radiologists performing X-ray guided endovascular treatment of abdominal aortic aneurysms (AAA). Calibrations were done with X-ray qualities N-40, N-60 and N-300 and with the beta source 90Sr + 90Y. Annual doses were estimated for the nuclear medicine staff and the orthopaedic surgeons. The mean annual finger dose to nuclear medicine staff exposed to 99Tc(m) was estimated to be 18.8 mSv, and the mean annual finger dose to surgeons performing X-ray guided orthopaedic surgery was 13.7 mSv. The surgeons and radiologists performing X-ray guided endovascular treatment of AAA received a mean finger dose of 0.35 mSv per treatment. The majority of researchers handling 32P received no finger dose at all, and the maximum reading was 1.65 mSv. All occupational groups received finger doses well below the annual finger dose limit of 500 mSv.