The clinical importance of changes in Treg and Th17 lymphocyte subsets in splenectomized patients after spleen injury.

BACKGROUND

Splenectomized patients are more prone to bacterial infections due to their immunocompromised status. Little is known about the role of T helper 17 (Th17) and T regulatory cells (Treg) in the immune system of patients after the removal of the spleen.

OBJECTIVES

The aim of the present study was to analyze possible changes in CD4+ lymphocyte T subsets, especially Treg and Th17, in patients who had undergone splenectomy.

MATERIAL AND METHODS

The study included a group of 67 male patients (41.74 ±16.22 years). All patients had undergone splenectomy because of spleen injury. Mean time elapsed from splenectomy to analysis was 9.1 ±4.6 years. Control samples were obtained from 20 male healthy volunteers. The percentages and absolute counts of Th17 and Treg were measured using the flow cytometry method.

RESULTS

The analysis of the antibody titer against 23 serotypes of Streptococcus pneumoniae (S. pneumoniae) in the splenectomized patients revealed its elevated values compared to controls (p = 0.0016). Higher percentages and absolute counts of Treg cells were found in the splenectomized group vs controls (p < 0.000007). Lower percentages and absolute counts of the Th17 subset were found in the study group vs controls (p < 0.000002 and p < 0.00006, respectively). The Treg cell percentage was positively correlated with the antibody titer against S. pneumoniae (p < 0.02). Th17 cells were reversely correlated with the antibody titer (p < 0.004 and p < 0.001 for absolute counts and percentage values, respectively). The Th17 subset values were significantly lower in the splenectomized patients who reported a higher frequency of upper respiratory tract infections (URTI) (p < 0.0001). No correlations were found between the time elapsed since splenectomy and the Treg or Th17 cell values in the study group.

CONCLUSIONS

Splenectomy results in an important deterioration of the Treg/Th17 cell balance with a predominance of immunoregulatory Tregs, which can contribute to insufficient immune response to infection.