Dottore GR, et al. - Researchers probed the relationship between orbital lymphocytic infiltrate and graves orbitopathy (GO) clinical features. T and B lymphocytes infiltrating orbital tissues were associated with the activity of GO, this possibly enhanced the experts' understanding of the association between GO immunologic features and clinical expression.

Methods

• Authors conducted a cohort study aimed at assessing the extent and immunohistochemical phenotype of orbital lymphocytes and associating it with the ophthalmologic features of GO, especially its clinical activity score (CAS), at a tertiary referral center.
• They included 20 consecutive patients with GO who underwent orbital decompression.
• They conducted this study from January 1 to May 31, 2017.
• The exposures included orbital tissue histology and immunohistochemistry testing as well as ophthalmologic evaluation.
• Main outcomes and measures were the association between CAS and orbital lymphocytes, analyzed as total number of lymphocytes and main lymphoid subsets.

Results

• As per data, the patient population included 8 men and 12 women, all of white race, with a mean (SD) age of 46 (13) years.
• Findings suggested that with an established cutoff value of 300 lymphoid cells per tissue sample, lymphocytes above this value were found in orbital tissues of 9 of 20 patients (45%), often organized into distinct foci.
• Results demonstrated that the lymphocytes comprised a mixture of T (CD3-positive) and B (CD20-positive) cells, suggesting a mature, polyclonal autoimmune response.
• The total number of lymphocytes as well as the number of CD3- and CD20-positive subsets, in a simple linear regression model correlated with CAS (R = 0.63; 95% CI, 0.27-0.84;P=.003; R = 0.59; 95% CI, 0.20-0.82;P=.006; and R = 0.65; 95% CI, 0.30-0.85;P=.002, respectively).
• Authors noted that in a multiple linear regression model, when adjusted for 2 additional variables that were correlated with CAS-smoking and GO duration lymphocytes maintained their effect on CAS-highlighting even more the important role of orbital lymphocytes in affecting CAS (total number: R = 0.58; 95% CI, 0.18-0.82; P = .01; CD3-positive: R = 0.58; 95% CI, 0.17-0.82; P=.01; and CD20-positive: R = 0.59; 95% CI, 0.19-0.83; P=.01).