T follicular helper cells (Tfh) have been recognised in minor salivary glands (MSG) of patients with primary Sjögren's syndrome (pSS). Nevertheless, if the Tfh1, Tfh2, Tfh17, Tfr phenotype is different when comparing pSS and associated SS in systemic lupus erythematosus (SLE) is unknown.
We included MSG biopsies from 8 pSS, 8 SLE/SS patients, 7 SLE patients, and 2 non-SS sicca patients. To determine the subpopulation of Tfh, a double-staining procedure for transcription factor B cell lymphoma 6 (Bcl-6)+/IL-17A+, Bcl6+/IL-4+, Bcl6+/IFN-γ+, and Bcl6+/Foxp3+ cells was performed. We estimated the mean percentage of positively staining cells in four ﬁelds per sample.
Tfh1, Tfh2, and Tfh17 cells were highly expressed in pSS compared with the rest of the groups; conversely, in patients with SLE/SS predominated, the Tfh17 and in SLE patients the Tfh1 cells. Regulatory Tfh cells (Tfr) were similar in pSS and the rest of the patients. However, the lowest frequency was found in the SLE group. A positive correlation was observed between anti-Ro/SSA autoantibody and Tfh17 subset (r=0.726, p=0.0001); and with the (Tfh2+Tfh17)/Tfh1 ratio (r=0.844, p<0.0001) in the MSG of patients with pSS.
We showed a differential Tfh profile in primary SS and SLE with associated SS. Whether this Tfh differential profile participates in the increased risk of lymphoproliferative disease in pSS compared with associated SS, or other outcomes, is yet to be determined in future studies.