Seasonal patterns of myositis-specific and myositis-associated autoantibodies in Italy: Seasonal patterns of myositis autoantibodies.

Objective: Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of systemic autoimmune disorders affecting skeletal muscles but also other organs. There are different forms of IIM, each with peculiar clinical manifestations and prognosis. Accordingly, several autoantibodies have been described in IIM, with different prevalence in the different forms of the disease.

FLT3L governs the development of partially overlapping hematopoietic lineages in humans and mice.

FMS-related tyrosine kinase 3 ligand (FLT3L), encoded by FLT3LG, is a hematopoietic factor essential for the development of natural killer (NK) cells, B cells, and dendritic cells (DCs) in mice. We describe three humans homozygous for a loss-of-function FLT3LG variant with a history of various recurrent infections, including severe cutaneous warts. The patients' bone marrow (BM) was hypoplastic, with low levels of hematopoietic progenitors, particularly myeloid and B cell precursors.

Presentation and progression of MPO-ANCA interstitial lung disease.

The association between MPO-ANCA-associated vasculitis (AAV) and interstitial lung disease (ILD) has been well established. Pulmonary fibrosis may coexist with, follow, or even precede the diagnosis of AAV, and its presence adversely affects the prognosis. The optimal approach to investigating ANCA in patients with ILD remains a subject of ongoing debate.

The immunopathological landscape of human pre-TCRα deficiency: From rare to common variants.

We describe humans with rare biallelic loss-of-function variants impairing pre-α T cell receptor (pre-TCRα) expression. Low circulating naive αβ T cell counts at birth persisted over time, with normal memory αβ and high γδ T cell counts. Their TCRα repertoire was biased, which suggests that noncanonical thymic differentiation pathways can rescue αβ T cell development.