Rickettsial and viral antibodies in multiple sclerosis

Lack of correlation between impaired interferon production and natural killer activity of lymphocytes in multiple sclerosis

The ability of lymphocytes from patients with multiple sclerosis (MS) to produce Interferon (IFN-alpha) in response to Newcastle Disease Virus (NDV) was studied in vitro. The correlation between individual IFN-alpha titers and natural killer (NK) cell activity and the presence of HLA system antigens associated with MS (B-7 and DRW-2) was also investigated. Lymphocytes from MS patients showed a significantly impaired capacity to synthesize IFN-alpha in vitro when compared to lymphocytes from healthy donors (mean titers: 85.9 I.U. and 268.2 I.U., respectively). Marked differences in IFN-alpha titers were observed in the group of MS patients. The production of IFN-alpha by the patients' lymphocytes did not correlate with either the activity of NK cells or with their stimulation by exogenous IFN-alpha. There was also no correlation between IFN-alpha production by lymphocytes from MS patients and the presence or absence of B-7 and DRW-2 antigens.

Association between HLA B7, DR2 and dysfunction of natural- and antibody-mediated cytotoxicity without connection with the deficient interferon production in multiple sclerosis

In this study, 133 patients with MS were investigated for HLA-A,B,C,DR antigens, natural killer (NK) cell activity, and antibody-mediated cytotoxicity (ADCC). A higher frequency of HLA B7 and DR2 was found in this group of patients than in the healthy control group, as can be observed in other caucasoid populations as well. In Gypsies living in the same geographic area, almost a complete absence of the disease was observed, corresponding to a lack of B7; however, HLA DR2 was present in 56% of this population. NK activity and ADCC measured against the K-562 tumor cell line was found to be significantly lower in MS patients, most pronounced in the group of male patients. Interferon augmentation of NK activity showed similar impairment in the patient group, and their lymphocytes produced a significantly lower amount of interferon. A correlation was demonstrated between both killer cell function and HLA B7, DR2 in MS patients, however, it was significant only in the case of ADCC and DR2. No other correlations were found in relation to interferon augmentation, interferon production, and HLA antigens. The above finding underscores a possible HLA-linked pathogenetic role of NK and K cell dysfunction in MS. This is consistent with other, similar observations that a possible defect in virus immunity may exist in MS patients.