SOCS in situ expression in tuberculous lymphadenitis in an endemic area

BackgroundThe immune response to Mycobacterium tuberculosis is complex and multifactorial, the cytokine system being a major factor in M. tuberculosis immunity.AimTo analyze the immunohistochemical aspects of tuberculous lymph nodes in immunocompetent patients and search for associations between SOCS and cytokine expression in human tuberculous lymphadenitis.MethodsThirteen lymph nodes were assayed by immunohistochemistry for SOCS-1 and 3, STAT-3, RANTES, MIP-1-α, ICAM-1, IFN-γ as well as CD45RO, CD20, CD34, CD68, trypsin and lysozyme. Additionally, the RT in situ PCR was performed for SOCS-1 and 3 mRNA detection.ResultsDecreased MIP-1α expression together with reduced SOCS-3 (p = 0.042), lysozyme (p = 0.024) and CD45RO (p = 0.05) was observed in the TB lymph nodes compared to the control lymph nodes. In conclusion, the lymphadenitis due to M. tuberculosis was associated with a downregulation of memory T cells (CD45RO), activated lysozymes and SOCS-3 compared to controls, which may play a role in the long-term bacterial replication and altered immune modulation characteristic of the disease.