Increased intratumor Valpha24-positive natural killer T cells: a prognostic factor for primary colorectal carcinomas.
OBJECTIVE
Human invariant natural killer T (NKT) cells are novel, distinct lymphocyte populations with a restricted T-cell receptor repertoire (Valpha24-Vbeta11). They play a pivotal role in immunoregulation and in antitumor activities. This study focused on Valpha24+ NKT cells in colorectal carcinomas and their clinicopathologic significance.


METHODS
Valpha24+ NKT-cell infiltration immunohistochemistry was studied in a total of 103 colorectal carcinoma cases. The degree of NKT-cell infiltration in tumors was evaluated as low (<7 NKT cells/5 HPF) or high (> or =7 NKT cells/5 HPF). The correlation between the degree of infiltrated Valpha24+ NKT cells and clinicopathologic variables was studied statistically.


RESULTS
A small number of Valpha24+ NKT cells were found in the normal colorectal mucosa (2.6 +/- 3.7 cells/5 HPF); however, their number increased remarkably in colorectal carcinomas (15.2 +/- 16.3 cells/5 HPF; P = 0.0003) and a majority showed phenotype of activation. Higher NKT-cell infiltration was more frequent in women than in men (P = 0.034) and correlated with fewer lymph node metastases (P = 0.042). Patients with high NKT-cell infiltration showed higher overall (P = 0.018) as well as disease-free (P = 0.0006) survival rates. Intratumor NKT-cell infiltration was an independent prognostic factor for the overall (P = 0.033) and disease-free (P = 0.0064) survival rates.


CONCLUSIONS
Increased infiltration of Valpha24+ NKT cells was observed in colorectal carcinomas. Higher Valpha24+ NKT-cell infiltration in colorectal carcinomas was an independent prognostic factor for favorable prognosis.
Tachibana
Tsuyoshi
T
Department of Surgery and Surgical Basic Science, Graduate School of Medicine, Kyoto University, Kyoto, and Shiga Medical Center for Adults, Shiga, Japan.
Onodera
Hisashi
H
Tsuruyama
Tatsuaki
T
Mori
Akira
A
Nagayama
Satoshi
S
Hiai
Hiroshi
H
Imamura
Masayuki
M
D000368:Aged; D000954:Antigens, Surface / Q000032:analysis; D019002:CD56 Antigen / Q000032:analysis; D018959:CD57 Antigens / Q000032:analysis; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007694:Killer Cells, Natural / Q000276:immunology / Q000473:pathology*; D037181:Lectins, C-Type / Q000032:analysis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D055651:NK Cell Lectin-Like Receptor Subfamily B; D011379:Prognosis; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis*; D016019:Survival Analysis; D015996:Survival Rate
D000954:Antigens, Surface; D019002:CD56 Antigen; D018959:CD57 Antigens; C527203:KLRB1 protein, human; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B; D016693:Receptors, Antigen, T-Cell, alpha-beta