Thyroid cell survival in coculture with autologous peripheral or intrathyroidal lymphocytes.
OBJECTIVE
We have studied lymphocyte induced cytotoxicity and the production of interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) during coculture of thyrocytes and autologous lymphocytes from patients with Graves' disease and from normal subjects.


METHODS
Thyroid tissues and lymphocytes were obtained from 28 patients with Graves' disease and from 9 control subjects.


METHODS
Lymphocyte induced cytotoxicity was evaluated on autologous thyrocytes using 5 metabolic tests: the MTT assay, the neutral red uptake, lactate dehydrogenase measurement and glutathione assay. IFN-gamma and TNF-alpha measurements were performed after 1, 5 or 7 days' coculture.


RESULTS
The lymphocytes isolated from peripheral blood (PB lymphocytes) altered the morphology and the metabolism of autologous thyrocytes. The intrathyroidal lymphocytes isolated after Dispase digestion were not toxic whereas mechanically isolated lymphocytes exerted a little toxicity. No difference was seen between Graves' disease and normal cells. The supernatants from cocultures had higher IFN-gamma levels than those from lymphocyte cultures. In coculture, PB lymphocytes secreted more IFN-gamma and TNF-alpha than intrathyroidal lymphocytes. The PB lymphocyte induced cytotoxicity was not due to IFN-gamma and TNF-alpha alone.


CONCLUSIONS
Peripheral blood lymphocytes are cytotoxic in vitro to autologous thyrocytes whereas intrathyroidal lymphocytes exert little or no cytotoxicity according to their isolation method. The mechanisms of lymphocyte induced toxicity remain to be explained.
Massart
C
C
Laboratoire de Biochimie A, CHU de Pontchaillou, Rennes, France.
Gibassier
J
J
Le Gall
F
F
Raoul
M L
ML
Beurtin
F
F
Genetet
B
B
Lucas
C
C
D000328:Adult; D017209:Apoptosis; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D005260:Female; D005978:Glutathione / Q000378:metabolism; D006111:Graves Disease / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism; D013961:Thyroid Gland / Q000276:immunology / Q000473:pathology*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D007770:L-Lactate Dehydrogenase; D005978:Glutathione