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HLA-B*07:510, a novel HLA-B allele with one exonic mutation identified in two Russian individuals., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Human leukocyte antigen (HLA) allele frequencies have a known association with the pathogenesis of various autoimmune diseases., Methods: We recruited 31 Indian patients of acquired dermal macular hyperpigmentation (ADMH) and 60 unrelated, age-and-gender-matched healthy controls. After history and clinical examination, 5 ml of blood in EDTA vials was collected. These samples were subjected to DNA extraction and the expression of HLA A, B, C, DR, DQ-A, and DQ-B was studied., Results: There was a predominance of females with a gender ratio of 23 : 8 and the most common phototype was Fitzpatrick type IV (83.9%). There was a significant association of HLA A*03:01 (OR: 5.8, CI: 1.7-17.0, P = 0.005), HLA B*07:02 (OR: 5.3, CI: 1.9-14.6, P = 0.003), HLA C*07:02 (OR: 4.3, CI: 1.8-9.6, P = 0.001), HLA DRB1*10:01 (OR: 7.6, CI: 1.7-38.00, P = 0.022), and HLA DRB1*15:02 (OR: 31.0, CI: 4.4-341.8, P < 0.001) with patients compared to controls, whereas HLA DQB*03:01 was less associated with patients compared to controls (OR: 0.2, CI: 0.0-0.6, P = 0.009)., Conclusion: Patients with ADMH are more likely to have the HLA A*03:01, HLA B 07*02, HLA C*07:02, HLA DRB1*10:01, HLA DRB1*15:02 and less likely to have the HLA DQB*03:01 allele. Larger cohort studies may thus be conducted studying these specific alleles., (© 2024 the International Society of Dermatology.)

Cross reactivities are known for human leukocyte antigen inside HLA-B7 related Cross-Reactive Group (B7CREG). Some CE-IVD flow-cytometry kits use double monoclonal antibodies (mAb) to distinguish HLA-B27 and HLA-B7 but practice reveals more complexes results. This study explores the performances of this test. Analysis of 466 consecutive cases using HLA-B27 IOTest™ kit on a Navios™ cytometer from Beckman-Coulter, partially compared to their genotypes. Expected haplotypes HLA-B27-/HLA-B7- (undoubtedly HLA-B27 negative) and HLA-B27+/HLA-B7- (undoubtedly HLA-B27+) were clearly identified according to the manufacturer's instructions. On the opposite, patients strongly labeled with anti-HLA-B7 showed three different phenotypes regarding anti-HLA-B27 labeling: (1) most of the cases were poorly labeled in accordance with cross reactivity inside B7CREG (HLA-B27-/HLA-B7+ haplotype); (2) rare cases had strong B7 and B27 labeling corresponding to HLA-B27+/HLA-B7+ haplotype; (3) even less cases had strong labeling by anti-HLA-B7 but non for anti-HLA-B27, all expressing HLA-B44 and no B7CREG molecules. Surprisingly, more cases were not labeled with anti-HLA-B7 antibody but partially labeled with anti-HLA-B27 suggesting another cross reactivity out of B7CREG. mAb HLA typing suggests new, cross reactivities of anti-HLA-B27 antibody to more molecules out of B7CREG and of anti-HLA-B7 antibody but not anti-HLA-B27 to HLA-B44 molecule also out of B7CREG. HLA-B27 could surely be excluded in most samples labeled with HLA-B27, below a "grey zone" on intermediate intensity. More comparison is needed in future studies., (© 2024 International Society for Advancement of Cytometry.)