Table 3.
Alterations and characteristics of parasite-induced thymic atrophy.
| Parasite | Reference | Histological and immunophenotype alteration | Molecular characteristic |
|---|---|---|---|
| Trypanosoma cruzi | (85, 86) (87, 88) |
1. Cortical thymocytes loss. 2. Apoptosis of thymocytes, especially DP thymocytes. 3. Migration disturbances. 4. Premature exit of thymocytes. |
a) Decrease in IL-2. b) Increase in IL-4,5,6, IFN-γ, TNF-α. |
| Leishmania infantum | (89, 90) | 1. Reduced cortical area. 2. Decreased proliferation and increased apoptosis. |
a) Reduced chemotactic factors and dysregulated of migratory factors. |
| Plasmodium berghei | (91–93) | 1. Loss of cortical-medullary delimitation. 2. Apoptosis of thymocytes especially DP and DN thymocytes. 3. Premature exit of thymocytes. |
a) Altered thymic microenvironment with significantly increased CXCL12 and CXCR4, decreased CCL25 and CCR9. b) Increased expression of ECM component, downregulated expression of laminin and FN receptor on thymocytes surface. |
| Plasmodium chabaudi | (94) | 1. Depletion of SP (CD4+ or CD8+) and δγ+ T cells. | |
| Plasmodium yoelii lethal (17XL) | (95) | 1. Depletion of DP and CD4+ SP thymocytes. 2. Reduced proliferation of DP thymocytes. 3. Downregulation of CD8 expression. |
|
| Plasmodium yoelii nonlethal (17XNL) | (95) | 1. Depletion of DN, DP, and CD4+ SP thymocytes. 2. Reduced proliferation of DN and DP thymocytes. |
|
| Angiostrongylus cantonensis | (96, 97) | 1. Depletion of CD3+, CD4+, and CD8+ T cells. 2. Increased thymocytes and thymic epithelial cells apoptosis. |
|
| Schistosoma mansoni | (98) | 1. Cortical thymocytes loss. 2. Loss of distinction in the corticomedullary region. |
|
| Schistosoma japonicum | (99, 100) | 1. Thymic atrophy but with both CD8+CD28- T cells and CD4+CD28- T cells increased. | a) Thymocytotoxic autoantibodies was found in thymus. |
DP, double positive; ECM, extra-cellular matrix; SP, single positive; DN, double negative.