Elevated levels of C-reactive protein and interleukin-6 in patients with obstructive sleep apnea syndrome are decreased by nasal continuous positive airway pressure

BACKGROUND

C-reactive protein (CRP) and interleukin (IL)-6 are important risk factors for atherosclerosis and coronary heart disease. In the present study, we examined serum levels of CRP and IL-6, IL-6 production by monocytes, and the effect of nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnea syndrome (OSAS).

METHODS AND RESULTS

After polysomnography, venous blood was collected at 5 AM from 30 patients with OSAS and 14 obese control subjects. Serum levels of CRP and IL-6 and spontaneous production of IL-6 by monocytes were investigated. In addition, the effects of 1 month of nCPAP were studied in patients with moderate to severe OSAS. Levels of CRP and IL-6 were significantly higher in patients with OSAS than in obese control subjects (CRP P<0.001, IL-6 P<0.05). IL-6 production by monocytes was also higher in patients with OSAS than in obese control subjects (P<0.01). In patients with OSAS, the primary factors influencing levels of CRP were severity of OSAS and body mass index and those influencing levels of IL-6 were body mass index and nocturnal hypoxia. nCPAP significantly decreased levels of both CRP (P<0.0001) and IL-6 (P<0.001) and spontaneous IL-6 production by monocytes (P<0.01).

CONCLUSIONS

Levels of CRP and IL-6 and spontaneous production of IL-6 by monocytes are elevated in patients with OSAS but are decreased by nCPAP. Therefore, OSAS is associated with increased risks for cardiovascular morbidity and mortality, and nCPAP may be useful for decreasing these risks.

Resolution of dyshidrotic dermatitis of the hand after treatment with continuous positive airway pressure for obstructive sleep apnea

Eczema of the palm and obstructive sleep apnea (OSA) are common disorders. Proinflammatory cytokines and cell adhesion molecules are elevated in both of these disorders. We describe an unusual patient with OSA who had recurrent free remission of dermatitis after treatment with continuous positive airway pressure. We speculate that the resolution of the patient's skin condition may reflect the effects of increased tissue oxygenation during sleep, reduced sleep fragmentation, and/or a reduction in sympathetic tone associated with successful sleep apnea treatment.

Acute effect of nasal continuous positive airway pressure therapy on the systemic immunity of patients with obstructive sleep apnea syndrome

OBJECTIVES

To investigate whether in patients with obstructive sleep apnea syndrome (OSAS) the systemic immunity is disturbed and whether it changes with nasal continuous positive airway pressure (NCPAP) therapy.

DESIGN

Polysomnography was performed on 18 OSAS patients (Group A) before NCPAP was started and again on the first night of NCPAP. Blood samples were collected at 8:00PM, 1:00AM and 6:00AM during each polysomnography. Lymphocyte subsets, lymphocyte blastformation, and natural killer (NK) cell activity were determined. Six normal subjects were also studied. A different six OSAS patients were studied over 6 days of NCPAP.

SETTING

N/A.

PATIENTS OR PARTICIPANTS

N/A.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

The only immunological parameter that significantly differed between the Group A OSAS patients either before or on the first night of NCPAP, and the normal subjects was the epinephrine level. Among the Group A OSAS patients, the following immunological parameters were significantly lower at 6:00AM on the first night of NCPAP than before NCPAP was started: percentage (49.4+/-1.9% before NCPAP vs 45.7+/-2.0% with NCPAP, mean+/-SEM, p<0.005) and absolute count of CD4+ cells (944.1+/-63.8 vs 829.6+/-71.3/mm3, p<0.05); absolute count of CD4+HLA-DR+ cells (91.9+/-13.3 vs 75.1+/-8.9/mm3, p<0.05); CD4+/CD8+ ratio (2.13+/-0.21 vs 1.91+/-0.18, p<0.05). The reduction in the percentage of CD4+ cells at 6:00AM was significantly correlated with the change in apnea-hypopnea index (AHI) (r=0.729, p<0.01). The CD4+ cell count recovered after 6 days of NCPAP. The lymphocyte blasfformation and NK cell activity levels did not change with NCPAP.

CONCLUSIONS

First-night NCPAP therapy reduced the CD4+ cell count after sleep, which recovered after one week of NCPAP. OSAS patients do not have immunological abnormalities.

[Malfunction of some immunologic functions in patients with obstructive sleep apnea]

Hypoxia and sleep disorders may result in an impairment of immune system in patients with obstructive sleep apnea (OSA). Therefore we studied mitogenic stimulation of peripheral blood lymphocytes by PHA (1 microgram/ml) by measurement of 3H-thymidine incorporation, metabolic activity of neutrophils measured by chemiluminescence (CL), immunoglobulins (IgG, IgA and IgM) concentration in serum (radial immunodiffusion) and TNF-alpha concentration in serum (ELISA), and E-rosette tests (with theophylline) in 57 obese patients with severe OSA. In OSA patients severe impairment of f-MLP-induced granulocyte chemiluminescent activity was observed.