Immunotherapeutic approaches in biliary tract carcinoma: Current status and emerging strategies

Table 1 Cellular mediators of innate and adaptive immune system in biliary tract carcinoma

Cell type	Frequency of infiltration	Clinical significance	Ref.
Natural killer cells	19.1%-33% overall	No correlation with disease stage, grade, or survival	[12,13]
	20% of ICC, 21% of ECC, 16% of GBC
Mast cells	2% of ICC, 2.5% of ECC, 8.5% of GBC	No correlation with survival	[13]
Macrophages	87% of ICC, 70% of ECC, and 71% of GBC	Associated with more advanced disease	[13]
Dendritic cells	Not determined	Associated with improved survival	[12,14]
CD4+ helper T-lymphocytes	43% of ICC, 30% of ECC, and 34%-51% of GBC	Associated with reduced probability of metastases and improved survival in ECC	[12,13]
CD8+ cytotoxic T-lymphocytes	46% of ICC, 49%-55% of ECC, and 38%-51% of GBC	Associated with reduced probability of metastases and improved survival in ECC	[12,13,15]
B-lymphocytes /plasma cells	4.5% of ICC, 6.7% of ECC, and 10.1% of GBC	Associated with improved survival	[13]

ECC: Extrahepatic cholangiocarcinoma; GBC: Gallbladder carcinoma; ICC: Intrahepatic cholangiocarcinoma.