TABLE 1.
List of pathogens detected in the thymus.
| Infectious agent | Alterations observed in the thymus | Type of infection (organism) | References | |
| Protozoa parasites | Leishmania infantum | Increased cortex:medulla index; altered abundance of extracellular matrix proteins and cell migration-related molecules; altered thymocyte homeostasis | Experimental (Mouse) Natural (Dog) |
(69, 70, 72) |
| Leishmania donovani | Not reported | Experimental (Mouse) | (71) | |
| Trypanosoma cruzi | Atrophy; alteration in extracellular matrix; depletion of DP cells; early export of DN/DP cells; increased expression of cell adhesion and cell migration-related molecules. | Experimental (Mouse) | (15, 73–76) | |
| Plasmodium berghei | Atrophy; histological alterations; increased apoptosis; DP cells depletion, changes in cell migration-related molecules, early release of DN/DP cells | Experimental (Mouse) | (77–79) | |
| Toxoplasma gondii | Atrophy; decreased thymic output; parasite-induced destruction of the thymic epithelium; altered thymic microarchitecture. | Experimental (Mouse) | (80, 81) | |
| Bacteria | Mycobacterium tuberculosis | Increased iNOS, IFN-γ and TNF expression | Experimental (Mouse) | (82–84) |
| Mycobacteria | Not reported | Natural (Human) | (85) | |
| Mycobacterium avium | Atrophy; pathogen-specific immune tolerance | Experimental (Mouse) | (82, 83, 86, 87) | |
| Salmonella Typhimurium | Atrophy; thymocyte apoptosis; depletion of DP cells | Experimental (Mouse) | (88, 89) | |
| Francisella tularensis | Atrophy; depletion of DP cells | Experimental (Mouse) | (90) | |
| Viruses | Influenza virus | Atrophy; Depletion DP cells; Decreased TCR repertoire diversity; Increased apoptosis index | Experimental (Mouse) | (91–93) |
| Mouse Hepatitis virus (MHV) | Atrophy | Experimental (Mouse) | (94–96) | |
| Human Immunodeficiency virus (HIV) | Atrophy; decreased thymic output; depletion of DP, CD4+ cells | Natural (Human) | (97–104) | |
| Zika virus | Cortical atrophy; alteration in extracellular matrix | Natural (Human) | (105, 106) | |
| Coxsackievirus | Hypertrophy; disruption of T cells export; sjTREC frequencies decreased; depletion of DP cells; altered TEC gene expression | Experimental (Mouse) TEC primary cultures (Human) |
(107–115) | |
| Cytomegalovirus (CMV) |
Atrophy; reduced IL-1 secretion | Experimental (Mouse) TEC primary cultures (Human) |
(116–119) | |
| Measles virus | Cortical atrophy; Depletion DP cells | Experimental (Mouse) | (120–122) | |
| Porcine reproductive and respiratory syndrome virus (PRRSV) | Atrophy; decreased thymic cortex; thymocyte apoptosis; thymic epithelial cell autophagy. | Experimental (Piglets) | (123, 124) | |
| Lymphocytic choriomeningitis virus (LCMV) | Atrophy; severe thymocyte depletion; impaired thymic negative selection; escape of self-reactive T cells; pathogen-specific immune tolerance | Experimental (Mouse) | (125, 126) | |
| Murine eucemia virus (MLV) | Atrophy; thymocyte apoptosis | Experimental (Mouse) | (127, 128) | |
| Herpesvirus: Murine roseolovirus (MRV) Mouse thymic virus (MTLV) |
Atrophy, thymic necrosis; T cell depletion | Experimental (Mouse) | (129, 130) | |
| Poliovirus | Not reported | Natural (Human) | (131) | |
| Epstein-Barr virus | Increased TLR7 and TLR9 expression in thymic epithelium | Natural (Human) | (132–134) | |
| Fungi | Paracoccidioides brasiliensis | Atrophy; histological disorganization; depletion of TEC, DP, CD4+, and CD8+ cells; defects in selection processes | Experimental (Mouse) | (135–137) |
| Cryptococcus neoformans | Changes in thymic architecture | Experimental (Rat) | (138, 139) |