The effect of antinuclear antibody titre and its variation on outcomes in children with primary immune thrombocytopenia.

Antinuclear antibody (ANA) can be positive in children with primary immune thrombocytopenia (ITP), but the effect of ANA titre and its variation on outcomes of children with primary ITP remains unclear. Here, we conducted a single-centre retrospective cohort study of children with primary ITP at the Peking Union Medical College Hospital in China. A total of 324 children with primary ITP included in this study were followed for a median time of 25 months. In this cohort, 39.2% had an ANA titre of 1:160 or higher. Results from a generalized estimating equation model revealed that patients with higher ANA titres had lower platelet counts at onset but a higher recovery rate of subsequent platelet counts. Results from Cox regression models adjusted for potential confounders revealed that patients with ANA titres of 1:160 or more were more likely to develop to autoimmune disease (AID) than those without, and the risk of AID development increased with the rise of ANA titres (p value for trend less than 0.001). These data highlight the predictive value of ANA titre for platelet counts and the risk of AID development in children with primary ITP.

The features of rare pathogenic BMPR2 variants in pulmonary arterial hypertension: Comparison between patients and reference population.

BACKGROUND: Mutations in the gene encoding bone morphogenetic protein receptor type 2 (BMPR2) are the most common genetic risk factors underlying pulmonary arterial hypertension (PAH). However, the features of PAH-related BMPR2 rare variants remain unclear. We propose that the discrepancy of BMPR2 rare variants landscape between patients with PAH and reference population would be important to address the genetic background of PAH-related variants. METHODS: We genotyped BMPR2 rare variants in 670 Chinese patients with pulmonary arterial hypertension. The BMPR2 rare variants were screened in 10,508 reference people from two exome databases. RESULTS: The prevalence of rare BMPR2 variants in patients with PAH was significantly higher compared to the reference population (21.5%, 144/670 vs 0.87%, 91/10508, p = 1.3 × 10-118). In patients with PAH, 49% of identified BMPR2 rare variants were loss-of-function or splicing. These BMPR2 rare variants were only observed in 1% of the reference population (p = 9.0 × 10-12). Arg491, which is absent in the reference population, represented as hot-spot site (14.6%, 21/144) in PAH patients. BMPR2 missense mutations in PAH patients were more likely distributed in extracellular ligand-binding domain (ECD, 29.7% vs 11.1%, p < 0.001). Compared with Non-PAH-related variations, PAH-related missense variants tend to alter the amino acid electric status (51.4% vs 23.3%, p < 0.001). CONCLUSIONS: BMPR2 variants located in extracellular ligand-binding domain or altered the amino acid electric status are more pathogenic.