Through single-cell transcriptomic analysis, Feng et al. identified a novel T follicular helper cell subset with stem cell–like transcriptional features and long-term survival ability, which gave rise to effector Tfh cells in recall immune responses.

Lui et al. describe a human LCK variant causing partial loss-of-function (LOF), including defective TCR signaling and T cell development. Using mouse models, they show that while complete LCK LOF results in SCID, partial LCK LOF causes CID with autoimmunity.

We show in polyclonal settings that GC B cell differentiation into plasma cells is affinity dependent, resulting in the generation of high-affinity serum responses. We profile GC cells poised for PC differentiation compared with GC B cells selected for further affinity maturation.

We established an Arl6ip1^−/− mouse model mimicking HSP with severe spastic paralysis and gait abnormalities. Neuroinflammation was identified as a key pathophysiological change. AAV9-ARL6IP1 delivery reduced limb paraplegia and gait abnormality, making ARL6IP1 a potential target for HSP gene therapy.

The work demonstrates that a primary oncogene of B-ALL (i.e., PAX5-ELN) confers stem cell–like features to a subset of committed B cell progenitors, converting them to quiescent/resistant pre-LSCs. Moreover, EGR1 represents a strong candidate to control the quiescence/resistance of murine pre-LSCs and of blasts from patients.

Solomon et al. establish that the Flt3⁺ multipotent progenitor (MPP4) compartment contains a quiescent/slow-cycling cell subpopulation, which has a prolonged in vivo hematopoietic potential and which constitutes a key transitional cell population between the hematopoietic stem cell and the lineage-biased MPP compartments.

The authors describe the first patient treated with a new cell therapy consisting of Tregs purified from pediatric thymus (thyTreg). 2 years after thyTreg administration in a heart-transplant child, no adverse effects have been reported and the peripheral Treg pool is preserved.