Soluble interleukin-6 receptor levels in pleural effusions.
Generation of soluble cytokine receptors is a general phenomenon, and the roles of several such receptors have been investigated in clinical settings. Unlike other soluble cytokine receptors, soluble interleukin-6 receptor (sIL-6R) can act as an agonist and thus is implicated as an important modulator in the acute-phase reaction of prolonged inflammation. The purpose of the present study was to determine the roles of pleural sIL-6R in both differential diagnosis of pleural diseases and in the induction of acute-phase protein. Specific sandwich enzyme-linked immunosorbent assays were used to determine sIL-6R and IL-6 in 19 tuberculous, 48 malignant and 10 transudative effusions. Although IL-6 levels in pleural effusions were strikingly different, no significant differences in pleural sIL-6R levels were found between the groups. Pleural levels of IL-6 were invariably much higher, whereas those of SIL-6R were invariably lower than serum levels. Furthermore, IL-6, but not sIL-6R, levels in effusions correlated significantly with serum C-reactive protein levels. These results suggest that: (1) pleural levels of sIL-6R are not increased even in strong inflammation such as tuberculous pleurisy, nor significantly different among pleural diseases; and (2) the local levels of sIL-6R are not as important as expected for the induction of acute-phase proteins in patients with pleural diseases.
Yokoyama
A
A
Second Department of Internal Medicine, Ehime University School of Medicine, Japan.
Kohno
N
N
Fujino
S
S
Abe
M
M
Ishida
O
O
Hiwada
K
K
D015703:Antigens, CD / Q000032:analysis*; D002097:C-Reactive Protein / Q000378:metabolism; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis; D010996:Pleural Effusion / Q000175:diagnosis / Q000276:immunology* / Q000378:metabolism; D016066:Pleural Effusion, Malignant / Q000276:immunology / Q000378:metabolism; D018123:Receptors, Interleukin / Q000032:analysis*; D019947:Receptors, Interleukin-6; D014396:Tuberculosis, Pleural / Q000276:immunology* / Q000378:metabolism
D015703:Antigens, CD; D015850:Interleukin-6; D018123:Receptors, Interleukin; D019947:Receptors, Interleukin-6; D002097:C-Reactive Protein