Deficiency of naive T cells in patients with sudden deafness

Although there are a number of reports concerned with the role of immunity in the sudden onset of progressive sensorineural hearing loss, there are few references dealing with the involvement of immune-mediated mechanisms in sudden deafness.

To study the phenotype of peripheral blood lymphocytes in a group of patients with sudden deafness by use of 3-color flow cytometry.

The study was carried out prior to the start of steroid therapy. Fourteen patients underwent a follow-up study once steroid therapy had been completed. Prospective analysis, case-control.

Tertiary case referral center, ambulatory and hospitalized care.

Twenty-two patients (13 men and 9 women; mean age, 45.3 years) were compared with 14 healthy control subjects (9 men and 5 women; mean age, 36 years). Patients were divided in 2 groups according to their response to steroid therapy.

Decreased numbers of both CD4+ helper cells (38.4% vs 45.5%; P = .04) and CD8+ cytotoxic cells (17.5% vs 22.3%; P = .02) were observed in patients and compared with those in the control subjects, as well as reduced numbers of CD4+CD45RA+ cells (14.4% vs 29.3%; P = .01) and CD8+CD45RA+ naive cells (18.2% vs 25.4%; P = .04). In the group of patients with a good response to steroid therapy (group 1), a tendency toward normalization of the CD4+ (pretreatment, 38.6%; posttreatment, 44.6%), CD4+CD45RA+ (pretreatment, 15.2%; posttreatment, 21.7%), and CD4+CD45RO+ (pretreatment, 21.1%; posttreatment, 18.2%) cell counts was observed, with a slight decrease in the CD8+ population (pretreatment, 18%; posttreatment, 15.7%). However, in patients with a poorer response (group 2), while there were increases in the CD4+ (pretreatment, 38%, posttreatment, 50%) and CD4+CD45RA+ (pretreatment, 12.8%; posttreatment, 16.7%) cell counts after steroid therapy, there was a significant increment in the CD4+CD45RO+ memory cell count (pretreatment, 14.1%; posttreatment, 28.5%) and low CD8+CD45RA+ counts (pretreatment, 14.6%; posttreatment, 15.5%). No differences were observed in the numbers of B or natural killer cells or in the presence of activation antigens CD25 and HLA-DR when pretreatment and posttreatment levels were compared.

These results demonstrate significant abnormalities in the subpopulations of lymphocytes in patients with sudden hearing loss, suggesting the existence of immune-mediated responses in the inner ear as possible etiopathogenic factors in this entity.