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.