The aim of this study is to evaluate the concentrations of interleukin-2, interleukin-10, interferon-gamma, PD1+ lymphocytes, and the interleukin-10 receptor expression in malignant and benign effusions.

In this prospective trial, 80 patients with pleural effusions and indication for thoracocentesis, drainage, indwelling pleural catheter (IPC) management and/or video-assisted thoracoscopic surgery are enrolled. The pleural effusion will be examined for different cytokines, cytokine-receptors, PD1-lymphocytes and CD4+/CD25+/Foxp3+ regulatory T cell.

Inclusion Criteria:

• age >18 years
• radiologically confirmed pleural effusion with an indication for puncture, pleural drain insertion, or video-assisted thoracoscopy for diagnostic and/or therapeutic reasons
• Signed declaration of consent

Exclusion Criteria:

• Withdrawal or cessation of participation

Patients with malignant or benign pleural effusions requiring diagnostic and/or therapeutic procedures including thoracocentesis, drainage insertion, indwelling pleural catheter (IPC) management, and/or video-assisted thoracoscopic surgery