Identification of HLA-DQA1 as a Susceptibility Gene for Spinal Tuberculosis by Exome Sequencing.

BACKGROUND Spinal tuberculosis (STB) is the main cause of bone and joint tuberculosis. This study aimed to screen and analyze the susceptibility genes for STB using whole-exome sequencing (WES). MATERIAL AND METHODS All exon regions of peripheral blood DNA from 6 STB patients were captured and sequenced using WES and the sequencing data were analyzed by modern bioinformatics methods to identify disease-causing mutations. Sanger sequencing was then used to validate the mutation sites in normal controls (207) and STB patients (193). The mRNA expression of the mutant gene and the serum levels of IL-6 and TNF-α were detected using qPCR or ELISA assay, respectively. RESULTS A nonsynonymous single-nucleotide polymorphism (SNP) in the gene HLA-DQA1 (rs796778515, c.592delCinsG, CAG to GAG, p.Q198E) was identified and further validated by Sanger sequencing. The percentage of the 3 genotypes C/C, C/G and G/G in STB patients and normal controls were 37.3%, 32.1%, and 30.6% and 47.8%, 33.8%, and 18.4%, respectively. Furthermore, the C>G mutation was significantly associated with the occurrence of STB. In addition, the levels of HLA-DQA1 mRNA were significantly lower in blood cells from STB patients compared with normal controls, while the serum levels of IL-6 and TNF-α were significantly higher. CONCLUSIONS The C>G mutation in the HLA-DQA1 gene was associated with the occurrence of STB. This variation may result in the decreased level of HLA-DQA1 mRNA and increased serum levels of IL-6 and TNF-α, which finally led the STB susceptibility.

Absence of autoreactive CD4+ T-cells targeting HLA-DQA1*01:02/DQB1*06:02 restricted hypocretin/orexin epitopes in narcolepsy type 1 when detected by EliSpot.

Narcolepsy type 1, a neurological sleep disorder strongly associated with Human Leukocyte Antigen (HLA-)DQB1*06:02, is caused by the loss of hypothalamic neurons producing the wake-promoting neuropeptide hypocretin (hcrt, also known as orexin). This loss is believed to be caused by an autoimmune reaction. To test whether hcrt itself could be a possible target in the autoimmune attack, CD4+ T-cell reactivity towards six different 15-mer peptides from prepro-hypocretin with high predicted affinity to the DQA1*01:02/DQB1*06:02 MHC class II dimer was tested using EliSpot in a cohort of 22 narcolepsy patients with low CSF hcrt levels, and 23 DQB1*06:02 positive healthy controls. Our ELISpot assay had a detection limit of 1:10,000 cells. We present data showing that autoreactive CD4+ T-cells targeting epitopes from the hcrt precursor in the context of MHC-DQA1*01:02/DQB1*06:02 are either not present or present in a frequency is <1:10,000 among peripheral CD4+ T-cells from narcolepsy type 1 patients.

Human leukocyte antigen DQ2.2 and celiac disease.

Patients with celiac disease (CD) lacking both human leukocyte antigen (HLA)-DQ2.5 in cis (DQA1*05:01, DQB1*02:01) or trans (DQA1*05:05, DQB1*02:02) configuration and HLA-DQ8 (DQA1*03:01, DQB1*03:02) are considered to be rare. Therefore, absence of these genotypes is commonly used to exclude the diagnosis of CD. To investigate whether this approach is justified, the HLA-distribution in 155 children with CD was studied. A total of 139 (89.7%) patients carried HLA-DQ2.5. Of the remaining patients, 7 (4.5%) carried HLA-DQ8. Interestingly, the 9 (5.8%) patients lacking HLA-DQ2.5 and HLA-DQ8 carried HLA-DQA1*02:01 and -DQB1*02:02 (HLA-DQ2.2). Therefore, HLA-DQ2.2 should be included as an important HLA-type related to CD.

Fulminant Type 1 diabetes in a pregnant woman as an initial manifestation of the insulin autoimmune syndrome.

Fulminant Type 1 diabetes is a subtype of Type 1 diabetes characterized by (1) abrupt onset of diabetes, (2) very short duration of hyperglycaemia with mildly elevated HbA(1c) (< 69 mmol/mol, 8.5%), (3) rapid progression to diabetic ketoacidosis, (4) very low C-peptide level, and (5) often associated with elevated serum pancreatic enzymes, and absence of diabetes-related autoantibodies. We encountered a case of fulminant Type 1 diabetes that developed with an initial manifestation of the insulin autoimmune syndrome and rapidly progressed to diabetic ketoacidosis during pregnancy. A 31-year-old Korean woman presented with recurrent sudden onset of sweating and change of consciousness during sleep at 19 weeks gestation. During a 72-h fasting test, hypoglycaemia (1.72 mmol/l) occurred at 4 h after the start of the test. At that time, there was a high insulin level (370.2 µU/ml), a paradoxically low C-peptide level (0.01 nmol/l) and a positive insulin autoantibody test. An oral glucose tolerance test revealed postprandial hyperglycaemia. She was initially diagnosed as the insulin autoimmune syndrome. On the day 5 of admission, she developed diabetic ketoacidosis. Her HbA(1c) was 62 mmol/mol (7.8%). The rapid progression of diabetic ketoacidosis altered the diagnosis to fulminant Type 1 diabetes. This case differed from typical fulminant Type 1 diabetes because it presented with hypoglycaemia, and positive insulin and anti-phospholipid antibody tests. Her HLA typing was HLA-DQA1*0302, 0501, HLA-DRB1*0301 (DR3), 0901(DR9). Her glucose level was subsequently very well controlled with multiple insulin injections and she successfully delivered a healthy baby.