Correlation of low numbers of intratumoral FOXP3+ cells with worse progression-free survival in angioimmunoblastic T cell lymphoma.

AIMS: Angioimmunoblastic T cell lymphoma (AITL) is a T cell lymphoma with aberrant immune activity. It is characterised by inflammatory and immune reactions. However, the impact of regulatory T (Treg) cells on AITL remains unclear.

METHODS

We retrospectively collected 46 AITL cases and performed immunohistochemical analysis of forkhead box P3 (FOXP3) expression. The number of immunostained FOXP3 cells was determined using a digital pathology system with whole-slide imaging. The average number of FOXP3+ cells per high-power field (HPF) was determined by randomly counting 20 HPFs. AITL cases were categorised into high-expression and low-expression groups based on the median count of FOXP3+ cells in all analysed samples. The relationship between FOXP3 expression and clinicopathological features was assessed.

RESULTS

Among the studied patients, 14 (30.4%) were females and 32 (69.6%) were males, and the median age at diagnosis was 64.1 years. The median expression of FOXP3 was 84.9 positive cells/HPF. FOXP3 expression negatively correlated with Epstein-Barr virus-encoded small RNA positivity in tumour (p=0.041). The patients with low FOXP3 expression presented with aggressive clinical behaviour, including advance-staged diseases (p=0.043), splenomegaly (p=0.008), B symptoms (p=0.019) and extranodal involvement (p=0.019). The neutrophil-to-lymphocyte ratio was higher in the patients with low FOXP3 expression, compared with those with high FOXP3 expression. Low FOXP3 expression had an adverse effect on progression-free survival (PFS, p=0.033), and increased the risk of recurrence 2.320-fold (HR 2.320 (95% CI 1.109 to 4.856); p=0.025).

CONCLUSIONS

Patients with AITL with low FOXP3 expression tend to have aggressive clinical presentation and shortened PFS. These findings may help with risk stratification and determination of new treatment strategy.