Background/Purpose: Relapsing polychondritis (RP) is an uncommon systemic connective tissue disorder characterized by recurrent and episodic inflammation of cartilaginous tissues, such as ear, nose, joint, and respiratory tract. Recently, some researches suggest that immune disorders lead to autoimmune diseases. But little research has been done on the status of immune function in RP patients. Therefore, we analyzed the lymphocyte subsets in peripheral blood of RP patients to explore their immune function. Therefore we analyzed absolute counts and percentages of lymphocyte subsets and CD4+T subsets in peripheral blood of RP patients to explore their immune function and laid a foundation for further treatment.

Methods: Absolute counts and percentages of peripheral blood lymphocyte subsets and CD4+T subsets, which were from 17 patients (8 women and 9 men) diagnosed as RP and 17 healthy controls, were assessed  by flow cytometry and compared. All statistical analyses were performed with SPSS v. 22.0. Continuous variables were reported as median. For all study variables, comparison among controls and RP subjects was based on the non-parametric Wilcoxon Mann-Whitney exact test. For all analyses, we used two-sided tests, with p-values < 0.05 denoting statistical significance.

Results: Our study recruited 17 patients who met the inclusion criteria. The average age of patients was 45.23 year. As shown, when compared with healthy controls, RP patients had lower absolute counts of T cells (1573.00/μl vs. 1092.00/μl, p=0.002), CD4+ T cells (913.00/μl vs. 620.09/μl, p=0.003), and NK cells (341.00/μl vs. 203.00/μl, p=0.02). No difference was reported when comparing the percentage and absolute number of B cell, the percentage of CD8+T cells and the ratio of CD4+/CD8+ T cells between RP patients and healthy group. In CD4+ T cells, the proportion and absolute counts of Treg cells were significantly reduced in RP patients in comparison with controls (proportion, 3.80% vs. 5.21%, p< 0.001; absolute counts, 24.28/μl vs. 46.33/μl,p=0.001). The absolute counts of Th2 cells was reduced in RP patients in comparison with controls (7.44/μl vs. 10.22/μl, p=0.031). But there were no significant difference between the percentage and absolute counts of Th17 or Th1 cells in patients with RP and healthy controls. But RP patients had higher ratio of Th17/Treg (0.25 vs. 0.13, p=0.001), Th1/Treg(3.33 vs. 1.95, p=0.018).

Conclusion: Our data suggested that the immune-inflammation in RP patients may be related to the depletion of NK cells and Treg cells. The relative decrease of Treg cells may lead to the relative increase of helper T cells, which leads to uncontrollable inflammatory response.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-study-of-peripheral-blood-lymphocyte-subsets-and-cd4t-subsets-in-recurrent-polychondritis/