Cognitive impairment is associated with altered blood cell profiles in aggressive lymphoma

Cognitive and psychological symptoms in neuropsychiatric disorders have been linked to blood cell parameters, including neutrophil-to-lymphocyte ratios (NLRs), systemic immune-inflammation indices (SIIs), and platelet-to-lymphocyte ratios (PLRs). It remains unclear whether cognitive impairments in haematological cancers are associated with biological vulnerabilities reflected in these parameters. We examined whether cognitive and psychological morbidity correlated with blood cell parameters before, during, and after chemotherapy in individuals with aggressive lymphoma.

Neuropsychological testing and self-reported questionnaires were administered at diagnosis, mid-chemotherapy, and 6-8 weeks post-treatment (n = 30). Regression models assessed associations between cognition and blood cell parameters. Bootstrapped Pearson correlations examined relationships between NLRs, SIIs, PLRs, and psychological symptoms. To test specificity, similar analyses were conducted in healthy controls (n = 72).

In individuals with aggressive lymphoma, NLRs, SIIs, and PLRs correlated with impairments in inhibitory control, cognitive flexibility, delayed recall, and working memory across time points (p < 0.05). A disconnect emerged between these parameters and subjective self-reports. At diagnosis, lower NLRs, SIIs, and PLRs were associated with worse objective cognitive performance but better perceived cognition. Mid-chemotherapy, higher NLRs correlated with worse delayed recall but fewer reported depression and anxiety symptoms (p < 0.05). No significant associations were observed in healthy controls.

Cognitive impairment was associated with blood cell parameters in individuals with aggressive lymphoma, indicating distinct biological patterns of dysfunction before, during, and after chemotherapy. The disconnect between objective neuropsychological performance and subjective self-reports reinforces the value of incorporating biomarkers into cognitive assessments in this population.