Tracking Immune Clues: How B-Cell and Cytokine Signatures Reveal the Severity of Combined Immunodeficiency

Understanding why some patients with monogenic combined immunodeficiencies (CID) experience severe disease while others do not remains a key challenge in clinical immunology. A new study led by Paola Suhet and colleagues, published in The Journal of Allergy and Clinical Immunology (2025), takes a major step toward answering that question by profiling immune cell subsets and soluble biomarkers across 56 patients with genetically defined CIDs.

Using the Immune Deficiency and Dysregulation Activity (IDDA v2.2) score, the researchers stratified patients into “IDDA-low” and “IDDA-high” groups, uncovering patterns that tracked closely with clinical severity. Patients in the IDDA-high category showed expansion of activated naïve (aN) T-bet⁺ B cells and T follicular helper (TFH) cells—immune features reminiscent of chronic activation and dysregulation. Elevated serum markers such as BAFF and soluble IL-2 receptor (sIL2R) mirrored these cellular changes, aligning with more severe immune-mediated manifestations.

Interestingly, regulatory T cells (Tregs) appeared suppressed as TFH numbers rose, hinting at a loss of immunological balance driving pathogenic inflammation. Among genetic subtypes, NFKB1 deficiency stood out as the most symptomatic, reinforcing its established role in immune homeostasis breakdown.

By linking immunophenotypic fingerprints with clinical activity, Suhet et al. reveal that even across diverse genetic defects, common themes - B-cell hyperactivation and cytokine imbalance - shape disease course. This integrative approach could refine how physicians monitor CIDs, moving beyond genotype to functionally track immune dysregulation in real time.

References:

https://www.sciencedirect.com/science/article/pii/S0091674925020226