Clinical Impact of CD8+ Cells in Hodgkin Lymphoma Lymphadenopaties. Contribution of Flow Cytometry

CONTEXT:Microenvironment of Hodgkin and Reed Sternberg(H-RS) cells is a current focus of interest to define risk and predict evolution of HodgkinÕs Lymphoma.

OBJECTIVES:To determine the role of infiltrating CD8+ cells, using flow cytometry (FCM), in the evolution of patients with HL.

DESIGN:Cell suspensions obtained after mechanical disintegration of ganglion biopsies of patients with newly diagnosed HL were analyzed using FCM. Definitive diagnosis was made by conventional histology and immunohistochemistry. Clinical data were collected from medical records. Statistical analysis was performed using SPSS 20.0 software.

SETTING:In the University Hospital of Salamanca, we consecutively analyzed by FCM all lymph nodes with suspected lymphoma at diagnosis. There was no selection bias when collecting patients, except for some cases with inadequate quality(insufficient cells).

PATIENTS OR OTHER PARTICIPANTS: From 1996(earliest available FCM data) to 2014, 104 of that samples had a definitive diagnosis of HL. Treatment depended on stage: a)early diagnosis received ABVD(x3) & local radiotherapy(RT) (20-30 Gy), b)advanced: ABVD(x6 to 8), plus RT in selected cases. Median follow-up was 10 years.

INTERVENTIONS:This was a retrospective observational study.

MAIN OUTCOMES MEASURES:Primary end points were overall survival(OS) and freedom from treatment failure(FFTF), considered from diagnosis to progression or relapse .

RESULTS:Most cells obtained were lymphocytes (Median17.1±86.9%) with a T/B/NK distribution of 72%/27%/1.6%(median) and predominance of CD4+ (median CD4:51%-CD8:12%). Median CD8+ cells(12%) was used to divide patients into 2 groups. FFTF was longer in patients with more than 12% of CD8+cells(93% vs. 71%, p=0.01). When analyzed separately patients with early/advanced disease, the clinical benefit remained in the group with advanced disease (p=0.006), whereas the statistical significance was lost in the group with early disease, possibly due to the excellent prognosis for those patients(FFTF 10 years > 95%). No differences were observed in the OS, because second line therapy was highly effective. In the multivariate analysis using Cox regression, advanced stage (HR=9.6 with 95% CI 1.2 to 73.9) and>12% CD8+ tumor infiltrating T-cells were independent variables(HR=0.26, 95% CI 0.07 to 0.9).

CONCLUSIONS:Increased number of CD8+ in the H-RSC microenvironment of HL is associated with better FFTF, particularly in the advanced-disease group. This should be considered as a new biomarker to identify high-risk patients.