Decidua as a site of extrathymic V gamma I T-cell differentiation.
OBJECTIVE
Decidual tissue is an interface between the host and fetus, which is regarded as a natural allograft. We have reported the possible presence of extrathymic T cells in human decidua through the expression of recombinase-activating genes in the decidual CD16-CD56bright large granular lymphocytes.


METHODS
In this study we analyzed expression of TCR V gamma delta gene segments in peripheral lymphocytes and decidual and nonpregnant endometrial samples using RT-PCR and oligonucleotide hybridization.


RESULTS
Interestingly, a limited repertoire of V gamma gene segments were discovered in decidual lymphocytes of normal pregnancy when compared with peripheral lymphocytes, whereas usage of V delta gene segments were ubiquitous in peripheral and decidual lymphocytes. Strong expression of V gamma I gene segment, often exceeding 50% of total V gamma, were noted in all (13/13) pregnant decidual tissues obtained at different gestational stages. Interestingly, this predominance of V gamma I gene is also noted in nonpregnant endometrial samples and the decidua of patients with ectopic pregnancies.


CONCLUSIONS
Our results suggest the nature of decidual V gamma I T cells as possible suppressors of rejective maternal cytotoxic T cells during the maintenance of normal pregnancies.
Hayakawa
S
S
Nihon University School of Medicine, Department of Obstetrics and Gynaecology, Tokyo, Japan.
Shiraishi
H
H
Saitoh
S
S
Satoh
K
K
D000328:Adult; D002454:Cell Differentiation / Q000276:immunology; D003656:Decidua / Q000166:cytology* / Q000276:immunology*; D005260:Female; D006411:Hematopoiesis, Extramedullary / Q000276:immunology*; D006801:Humans; D011247:Pregnancy; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
D016692:Receptors, Antigen, T-Cell, gamma-delta