Table 1.
Changes in the frequency and function of immune cell population in endometriosis.
| Immune cell | Peritoneal fluid | Eutopic endometrium | Ectopic endometrium | Function |
|---|---|---|---|---|
| Macrophages | Increased M2 macrophages[4] | Increased macrophages in global[4] | Increased M2 macrophages[4] | Deficient cytotoxicity in eliminating refluxed fragments |
| Decreased M1 macrophages[4] | Decreased M1 macrophages[4] | Neurogenesis and neuroinflammation[85,90] | ||
| Angiogenesis[3] | ||||
| Promotion of lesion growth by M2 macrophages[3] | ||||
| Inhibition of lesion growth by M1 macrophages[3] | ||||
| NK cells | – | No differences in global[18] | – | Impaired uNK cell maturation[18] |
| Increased immature NK cells[18] | Deficient cytotoxicity in eliminating refluxed fragments[5,12] | |||
| Endometriosis-associated infertility[18] | ||||
| Induction of immune escape[16] | ||||
| DCs | No differences in global[19] | Increased immature DCs[20] | Increased immature DCs[20] | Impaired DC maturation[20] |
| Increased immature DCs[20] | Angiogenesis[22] | |||
| Promotion of lesion growth[22,24] | ||||
| Inhibition of lesion growth[25] (controversies) | ||||
| MDSCs | Increased MDSCs[26] | – | Increased MDSCs[27] | Immunosuppression |
| Promotion of lesion growth[28] | ||||
| CD8+ T cells | – | – | – | Deficient cytotoxicity in eliminating refluxed fragments[31] |
| CD4+ Th17 cells | Increased Th17 cells[34] | – | – | Promotion of ESC proliferation[37] |
| Angiogenesis[38] | ||||
| Pro-inflammation responses[38] | ||||
| Recruitment of macrophages and neutrophils[39] | ||||
| Induction of M2 macrophages[39] | ||||
| CD4+ Treg cells | Increased Treg cells[41] | Increased Treg cells[42] | Increased Treg cells[61] | Angiogenesis[45] |
| Induction of pro-repair macrophages[46] | ||||
| Promotion of lesion growth[47] | ||||
| Immunosuppression[47] | ||||
| CD4+ Th1 cells | – | – | Decreased Th1/Th2 ratio[48] | Proinflammatory immune responses[49] |
| CD4+ Th2 cells | – | – | Decreased Th1/Th2 ratio[48] | Anti-inflammatory immune responses[49] |
| Promotion of lesion growth[50] | ||||
| B cells | Increased B cells[52] | Increased B cells[61] | Increased B cells[52] | Aberrant production of autoantibodies[53] |
| Deceased B cells[52] | No differences[61] (controversies) | Deceased B cells[61] | Endometriosis-associated infertility[81,82] | |
| No differences[52](controversies) | No differences[52] (controversies) | Promotion of lesion growth[60] |
DCs: Dendritic cells; ESC: Endometrial stromal cell; MDSCs: Myeloid-derived suppressor cells; M1: Classically activated phenotypes of macrophages; M2: Alternatively activated phenotypes of macrophages; NK cells: Natural killer cells; Th: T helper; Tregs: Regulatory T cells; uNK: Uterine NK.