CASP8 and CASP3 mRNA Expression in Autoimmune Lymphoproliferative Syndrome (ALPS) and Chronic Immune Thrombocytopenia (ITP)

Background: Fas/FasL-mediated apoptosis is central to immune homeostasis and is implicated in autoimmune lymphoproliferative syndrome (ALPS) and immune thrombocytopenia (ITP). We aimed to compare whole-blood transcriptional levels of CASP8 and CASP3 across ALPS, chronic ITP, and healthy controls. Methods: CASP8 and CASP3 mRNA expression was quantified by real-time PCR in whole blood from clinically diagnosed ALPS patients, chronic ITP patients, and healthy controls. Results: CASP8 mRNA expression was significantly increased in ALPS and ITP versus controls (p = 0.0009 and p < 0.0001, respectively) and was lower in ALPS than in ITP (p = 0.0265). CASP3 mRNA was also increased in both patient groups versus controls (ALPS: p = 0.0045; ITP: p < 0.0001), with no significant difference between ALPS and ITP (p = 0.1692). Conclusions: ALPS and chronic ITP show distinct CASP8 transcriptional patterns and a shared upregulation of CASP3 at the whole-blood mRNA level. These findings are descriptive and do not directly assess caspase activation or apoptotic pathway activity; further protein- and cell subset-based studies are needed to clarify functional implications.