Evaluation of PR3- and MPO-ANCA line and dot immunoassays in ANCA-associated vasculitis.

OBJECTIVE: This study was performed to evaluate the diagnostic accuracy of novel line and dot immunoassays for detection of MPO and PR3 ANCA. METHODS: Sera from 50 patients with ANCA-associated vasculitis (AAV), including granulomatosis with polyangiitis and microscopic polyangiitis, and from 45 disease controls were tested by IIF and for the presence of PR3-ANCA and MPO-ANCA by four different line or dot immunoassays, as well as by a chemiluminescence immunoassay. RESULTS: The area under the curve of the receiver operating characteristic curve to discriminate AAV from controls was 0.858 (95% CI 0.785-0.931) for the IIF method. For the antigen-specific immunoassays, the area under the curve varied between 0.869 (95% CI 0.797-0.941) and 0.936 (95% 0.886-0.985). CONCLUSIONS: Our comparison of various ANCA detection methods showed a high degree of diagnostic precision for all of the PR3- and MPO-ANCA line and dot immunoassays investigated. The performance was equal to or better than the performance of IIF. These results indicate that novel line and dot immunoassays can serve as a first-line test method in patients with the suspected diagnosis of AAV.

Maternal and fetal PROGINS progesterone receptor polymorphism reduces the risk for transient tachypnea of the newborn.

BACKGROUND: Transient tachypnea of the newborn (TTN) is the most common perinatal respiratory disorder. It was suggested that the pathogenesis of TTN might involve altered activity of female sex hormones. This study analyzed whether the PROGINS progesterone receptor polymorphism, which is less responsive to progesterone, is associated with TTN. METHODS: A cohort of 2352 infants born to Caucasian women at the Obstetrics Department of the Charite was investigated prospectively. The collected information included the occurrence of respiratory disorders, birth weight, gestational age at delivery, mode of delivery, and maternal morbidity. Mothers and newborns were genotyped for the PROGINS progesterone receptor polymorphism. Statistical analyses considered correction for confounding factors. RESULTS: The presence of the mutated T2-allele either in mothers or in infants was associated with a reduction of the incidence of TTN in a gene dose-dependent manner (mothers T1/T1: 6.6%, T1/T2: 4.3% T2/T2: 2.3%, p < 0.01; infants T1/T1: 6.5%, T1/T2: 4.7%, T2/T2: 0.0%, p = 0.02 in a multivariable regression model). The total number of mutated T2-alleles present in a mother/child pair was associated with a reduction of TTN (4 T2-alleles: 6.4%, n=95; 3: 5.9%, n=30; 2: 3.1%, n=9; 1: 1.4%, n=1; 0:0%, n=0; p < 0.01 in a multivariable regression model). CONCLUSIONS: Both the maternal and fetal mutated alleles of the PROGINS progesterone receptor polymorphism seem to protect from TTN. The same phenotype occurs regardless of whether the mutation is localized in the mother or in the infant. Fetal as well as maternal T2-alleles synergistically reduce the risk for TTN in a gene dose-dependent manner.