{'fraction_non_alphanumeric': 0.02216427640156454, 'fraction_numerical': 0.009126466753585397, 'mean_word_length': 4.949612403100775, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Lack of NK cells and related cytokines in pleural effusion.

BACKGROUND
Relatively low number and activity of natural-killer (NK) cells have been reported in malignant pleural effusions. However, there has been no report on NK cells related cytokines.


METHODS
Lymphocyte subpopulations were studied in 30 cases of pleural effusion with various etiologies, along with peripheral blood, by using flow cytometry. The related cytokine levels in peripheral blood and pleural fluid, including IL-1 alpha, IL-4 and IL-12, were also analyzed with ELISA assays.


RESULTS
The results showed significant increase of T-helper cell subpopulation in pleural effusion of various etiologies. No obvious change of B-lymphocyte subpopulation between peripheral blood and pleural effusion was found. IL-4 was undetectable in both peripheral blood and pleural fluid in most cases. IL-1 alpha was detectable in some cases and the level was highest in pleural fluid of empyema. Decreased NK cells were found in most cases of pleural effusion and accompanied by undetectable IL-12 both in pleural fluid and peripheral blood. The only one case with detectable IL-12 concentration in pleural fluid was the one with tuberculous pleurisy.


CONCLUSIONS
Increased T-helper cell subpopulation and decreased NK cell subpopulation were found in pleural effusion of various etiologies. In spite of the small series of our patients, the decrease of NK cell subpopulation and the undetectable IL-12 concentration in pleural effusion deserves further investigations.