Cytolytic T cells with Th1-like cytokine profile predominate in retroorbital lymphocytic infiltrates of Graves' ophthalmopathy.
Lymphocytic infiltration of muscular and connective tissues of the retroorbital (RO) space is a histological hallmark of Graves' ophthalmopathy (GO). We have characterized some phenotypical and functional features of T cells derived from RO infiltrates of four GO patients who were submitted to orbital decompression. Fragments of RO tissue were cultured for 7 days in IL-2-conditioned medium in order to generate T cell lines of in vivo activated T cells. Phenotypical analysis of freshly isolated peripheral blood (PB) lymphocytes both from patients and four healthy controls showed a predominance of CD4+ T cells (CD4/CD8 ratios 1.9:2.5), whereas RO-derived T cell lines displayed almost equal proportions of CD4+ and CD8+ cells (CD4/CD8 ratios 0.9:1.2). RO T cell lines and PB T cells from patients and controls were then cloned using a high-efficiency cloning procedure. The phenotypical and functional features of 153 T cell clones (TCC) derived from RO infiltrates were examined and compared with those of 166 and 236 TCC derived from the PB of patients and controls, respectively. CD4/CD8 ratios ranged from 0.8-1.4 in the series of RO-derived TCC and from 1.9-2.2 in the corresponding series of PB-derived TCC. Assessment of lectin-dependent cytolytic activity showed similar proportions of cytotoxic clones in TCC derived from the PB of patients (37%) and controls (38%); most of the cytolytic TCC was CD8+. In contrast, the proportion of cytolytic RO TCC was markedly higher (106/153 = 69%), including 100% of CD8+ and the majority (59/79 = 75%) of CD4+ clones. When compared to TCC derived from the PB of both patients and controls, RO TCC showed remarkably high proportions of both CD8+ and CD4+ clones with a Th1-like cytokine profile, as documented by their ability to secrete IL-2, IFN-gamma, and tumor necrosis factor-alpha (TNF-alpha), but not IL-4 or IL-5. This study provides evidence that cytolytic T cells with Th1 profile of cytokine production predominate in RO infiltrates of GO, a pattern quite similar to those previously described in thyroid infiltrates of Hashimoto's thyroiditis or Graves' disease. The peculiar cytokine secretion profile of RO T cells may be of importance in the pathogenesis of both the tissue alterations and fibrogenic process observed in GO.
de Carli
M
M
Division of Clinical Immunology and Allergology, Institute of Clinica Medica 3, University of Florence, Italy.
D'Elios
M M
MM
Mariotti
S
S
Marcocci
C
C
Pinchera
A
A
Ricci
M
M
Romagnani
S
S
del Prete
G
G
D000328:Adult; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D016207:Cytokines / Q000378:metabolism*; D005260:Female; D006111:Graves Disease / Q000473:pathology*; D006801:Humans; D008214:Lymphocytes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000473:pathology*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D006377:T-Lymphocytes, Helper-Inducer / Q000378:metabolism
D015704:CD4 Antigens; D016827:CD8 Antigens; D016207:Cytokines