Depression of T cells in Bell's palsy

Role of T-lymphocyte subsets in facial nerve paralysis owing to the reactivation of herpes simplex virus type 1

CONCLUSION

Although both T-cell subsets are essential for inhibiting HSV-1 reactivation in the GG, CD4 + T cells play a more important role in host defense against virus replication.

OBJECTIVE

To elucidate the host immunological factors that participate in herpes simplex virus type 1 (HSV-1) reactivation in the geniculate ganglia (GG) and lead to facial paralysis, we developed a mouse model of facial paralysis that involved the reactivation of HSV-1 following general immune suppression.

MATERIAL AND METHODS

Eight weeks after recovery from primary facial paralysis caused by inoculating the auricle with HSV-1 the auricle was scratched and mice (n = 69) were given an i.p. injection of either anti-CD4 (n = 46) or anti-CD8 (n = 23) monoclonal antibody to deplete specific T-lymphocyte subsets. Following this reactivation procedure, the rate of recurrent facial paralysis was compared between the two models. The GG were examined histopathologically and using polymerase chain reaction to detect HSV-1 DNA.

RESULTS

Facial paralysis developed in 42% of mice in the anti-CD4 model and in 13% in the anti-CD8 model. HSV-1 DNA was detected in 50% of the mice in both models. Histopathologically, neurons were destroyed in parts of the GG and numerous virus particles were seen in the surviving neurons.

IgG index in acute idiopathic peripheral facial palsy

OBJECTIVES

Etiologic hypotheses in acute idiopathic peripheral facial palsy (AIPFP) mostly point to an immunologic dysfunction, probably virus-induced. Though various immunologic abnormalities are reported, the problem is still unsolved. We investigated intrathecal immunoglobulin synthesis in AIPFP as a clue for central nervous system (CNS) immunopathology.

MATERIAL AND METHODS

We studied IgG index in 24 patients with AIPFP, 10 with other neurological diseases (OND) and 17 with multiple sclerosis (MS). CSF and serum IgG were measured by radial immunodiffusion technique. IgG index is calculated according to Tibbling's formula.

RESULTS

IgG indexes were abnormal in 6 patients with AIPFP, 3 with OND and 10 with MS patients. There was no statistical difference between AIPFP and OND groups, while marked difference existed between AIPFP and MS groups.

CONCLUSION

Though IgG indexes were high in 25% of AIPFP patients, statistical analyses did not show any significance of this finding. Lack of a positive result might reflect non-existence of an extensive immunologic pathology within CNS, excluding a very limited one.

The HLA system and T-cell subsets in Bell's palsy

The etiology of Bell's palsy (BP) is still unknown, but infectious, immunological and genetic factors have been suggested to play a role in the pathogenesis of the disease. We analyzed blood samples of 92 Mexican Mestizo patients diagnosed as having BP according to established international criteria, and the results were compared to a group of apparently healthy controls of the same ethnic origin. HLA class I (A, B, C) and Class II (DR, DQ) products of the major histocompatibility complex (MHC), and the percentages of CD3, CD4 and CD8 T-cell subsets were investigated. The number of family antecedents was surprisingly high (46%), supporting a genetic basis. There was a slight increase of DRw13, suggesting a possible susceptibility class II-linked gene. A significant decrease of DR4 (pc = 0.001) was detected, which may indicate the existence of a resistance DR-linked gene. Thus, a non DR4 carrier may be in high risk of expressing BP. In the acute phase of the disease, the T-cell subsets showed a decrease in CD3 and CD4 cells when compared to controls. CD8 cells were increased in the same stage. A transient T-cell imbalance was thus observed which recovered in the convalescent phase. None of the patients with CD4 lower than 40% were DR4, suggesting that the DR-linked resistance gene may predispose to the T-cell defect.