Lu sur :https://www.ncbi.nlm.nih.gov/pubmed/29649594
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Detection of human parvovirus B19 infection in the thymus of patients with thymic hyperplasia-associated myasthenia gravis.
Gong L1, Li Y2, Li X3, Tu Q4, Mou X5, Wang S6, Wan Y7, Lu Q8, Wang J9, Zhang W10, Zhu S11, Han X12, Yao L13, Zhang J14, Huang G15, Zhang W16.
Clin Microbiol Infect. 2018 Apr 9. pii: S1198-743X(18)30298-2. doi: 10.1016/j.cmi.2018.03.036.
To investigate the association between human parvovirus B19 (B19V) infection in the thymus and myasthenia gravis (MG).
The presence of human B19V DNA and protein was assessed in 138 samples, including 68 thymic hyperplasia (39 with MG), 58 thymoma (23 with MG), and 12 normal thymus tissues, by nested polymerase chain reaction, immunohistochemistry, laser capture microdissection, and sequencing in a double-blinded manner.
B19V DNA was mainly detected in thymic hyperplasia, and the positive rate (41.18%, 28/68) was significantly higher than that in thymoma (3.45%, 2/58) (P<0.001), but not in normal thymic tissues. Correspondingly, the positive rate in thymic hyperplasia with MG (30.77%, 12/39) was significantly higher than that in thymoma with MG (4.35%, 1/23) (P=0.021). However, it was higher in thymic hyperplasia without MG (55.17%, 16/29) than in thymic hyperplasia with MG (30.77%,12/39) (P=0.043). B19V VP1/VP2 protein-positive cells in thymic hyperplasia (63.24%, 43/68) were mainly identified in ectopic germinal centers and thymic corpuscle epithelial cells, but were rare in thymoma (1.72%, 1/58) (P<0.001). Moreover, the positive rate was significantly higher in thymic hyperplasia with MG (74.36%, 29/39) than in thymic hyperplasia without MG (48.28%, 14/29) (P=0.027).
To our knowledge, the present study is the first to show that human B19V infection is closely associated with thymic hyperplasia and thymic hyperplasia-associated MG, but not related to thymoma or thymoma-associated MG. The findings revealed a previously unrecognized etiopathogenic mechanism of thymic hyperplasia-associated MG, evoking numerous questions that require further investigation.