Narcolepsy is characterized by excessive daytime sleep and cataplexy. Little is known about the possible difference in pathophysiology between patients with or without cataplexy.
Objective: To quantify T CD4, T CD8 and B lymphocytes in subgroups of patients with narcolepsy and the presence or absence of the HLA-DQB1*0602 allele between groups.
Method: Our study was prospective and controlled (transversal) with 22 narcoleptic patients and 23 health control subjects. Patients underwent an all-night polysomnographic recording (PSG) and a multiple sleep latency Test (MSLT). The histocompatibility antigen allele (HLA-DQB1*0602), T CD4, CD8 and B lymphocytes were quantified in control subjects and in narcoleptics.
Results: The HLA-DQB1*0602 allele was identified in 10 (62.5%) of our 16 cataplexic subjects and in 2 (33.3%) of the 6 patients without cataplexy (p=0.24). In control subjects, HLA-DQB1*0602 allele was identified in 5 (20%). A significant decrease in T CD4 and B lymphocytes was found in narcoleptic patients with recurrent cataplexy when compared with our patients without cataplexy.
Conclusion: Autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis were associated with a decrease in sub-group of T CD4 and B lymphocytes. A drop in B lymphocytes count in reumathoid arthritis might, it is posited, be correlated to the presence of HLA-DRB1 allele along with an overall worsened outcome of the affliction. The theory of an increase in consumption of B lymphocytes over the maturation phase has likewise been put forward. Our study reinforces the view that narcolepsy should be considered from an immunological perspective.