High numbers of tumor-infiltrating programmed cell death 1-positive regulatory lymphocytes are associated with improved overall survival in follicular lymphoma.
OBJECTIVE
Tumor microenvironment influences the behavior of follicular lymphoma (FL), although the specific cell subsets involved are not well known. The aim of this study was to determine the impact of programmed cell death 1 (PD-1) -positive inhibitory immunoregulatory lymphoid cells in the clinicobiologic features and outcome of patients with FL.


METHODS
We examined samples from 100 patients (53 men and 47 women; median age, 54 years) at diagnosis, as well as in 32 patients at first relapse, with a recently generated monoclonal antibody against PD-1. The cells were quantified using computerized image analysis. Additional analysis consisted of double immunofluorescence and flow cytometry.


RESULTS
PD-1 expression was alternative to FOXP3 in lymphoid cells from both reactive tonsils and FL. At diagnosis, the median percentage of PD-1-positive cells was 14% (range, 0.1% to 74%). Patients with grade 3 FL, poor performance status, and high serum lactate dehydrogenase showed lower numbers of PD-1-positive cells. After a median follow-up of 6.2 years, patients with PD-1-positive cells <or= 5% (n = 25), 6% to 33% (n = 50), and more than 33% (n = 25) had a 5-year progression-free survival rate of 20%, 46%, and 48% (P = .038) and overall survival (OS) of 50%, 77%, and 95% (P = .004), respectively. PD-1 and FL International Prognostic Index maintained prognostic value for OS in multivariate analysis. Patients with PD-1-positive cells <or= 5% showed a higher risk of histologic transformation. At that time, transformed diffuse large B-cell lymphomas had lower percentage of PD-1-positive cells than FL.


CONCLUSIONS
A high content of PD-1-positive cells predicted favorable outcome of FL patients, whereas a marked reduction is observed in transformation.
Carreras
Joaquim
J
Hematopathology Section, Department of Pathology, Hospital Clinic, Institut d'Investigacions Biomèdiques August Pi-Sunyer, University of Barcelona, Spain.
Lopez-Guillermo
Armando
A
Roncador
Giovanna
G
Villamor
Neus
N
Colomo
Lluis
L
Martinez
Antonio
A
Hamoudi
Rifat
R
Howat
William J
WJ
Montserrat
Emili
E
Campo
Elias
E
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000096:biosynthesis* / Q000276:immunology; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis* / Q000276:immunology; D005260:Female; D051858:Forkhead Transcription Factors / Q000096:biosynthesis / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D008224:Lymphoma, Follicular / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000276:immunology; D061026:Programmed Cell Death 1 Receptor; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D009363:Neoplasm Proteins; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor