Clinical Value Of Detecting Oligoclonal Bands In Central Nervous System Diseases

The intensive immunologic response in central nervous system (CNS) was the pathological foundation that generating and developing of some autoimmune CNS diseases. The discovery of the IgG type oligoclonal bands (OCB) in the cerebrospinal fluid (CSF) was a major step forward in the understanding of multiple sclerosis (MS) and other inflammatory CNS diseases. In normal state, the immunoglobulin in serum and CSF were polyclonal, but under some pathological circumstances, a certain number of abnormal plasma cells'clone proliferating and synthesizing the degeneration immunoglobulin called OCB, OCB were two or more than two clear protein zones which were separated, relatively narrow and discontinuous in theγ-globulin region during electrophoresis. OCB was a specific reaction for certain specific antigens in CNS. A positive result of OCB in CSF was a highly suggestive of abnormal immunoglobulin synthesis in CNS. The discovery of OCB led to the prevailing concept that MS was mediated by clonally expanded lymphocytes, and provided the basis for modern diagnostic procedures in MS.Applying isoelectric focusing electrophoresis (IEF) and immunoblotting method to detect OCB was recognized internationally as a gold standard to analyze intrathecal IgG synthesis. The European experts group recommended the following 5 types to describe OCB results: 1. Normal. There was no OCB detected both in serum and CSF; 2. OCB was limited in CSF but not in serum; 3. In addition to the communal OCB in CSF and serum there were still some specific belts in CSF; 4. The same OCB appeared both in CSF and serum; 5. The same monoclonal zone showed in CSF and serum. In the situation of that OCB existing in CSF but not in serum or in addition to the same OCB both in CSF and serum, there were other specific belts in CSF as the standard to judge intrathecal IgG synthesis (2, 3 type).The objects of this research were 110 cases of CNS diseases form Neurology department in the first hospital of Jilin university in January 2008~2010, including 33 cases of MS, 16 cases of Guillain Barre syndrome (GBS), 32 cases of inflammatory CNS diseases and 29 cases of non-inflammatory CNS diseases. The research applied IgG-IFE kit from Helena Corporation in the USA to detect IgG-OCB in paired serum and CSF samples, immunity scattering turbidimetry and improved pyrogallol red - molybdate to detect IgG and total protein (TP) levels in CSF, then analyzed the data statistically. The study analyzed the positive rate of OCB in different CNS diseases, applied five types which were generally recognized in the international to report OCB results, calculated CSF IgG/CSF TP ratio in CNS diseases, analyzed OCB results retrospectively in different gender, age, duration, activity and recrudescence times of MS patients and discussed the sensitivity and specificity of OCB and CSF IgG/CSF TP ratio in the diagnosis of MS patient in our country. The results showed that the total positive rate of OCB was 31.8%, the MS group was 57.6%, the GBS group was 50%, the inflammatory CNS diseases group was 21.9% and the non-inflammatory CNS diseases group was 3.4%. Theχ2 test results showed that the highest two positive rate of OCB were in MS and GBS groups, furthermore, there was no significant difference between them. A statistically significant difference of the positive rate of OCB findings between inflammatory and non-inflammatory CNS diseases groups, inflammatory CNS diseases group was significantly higher than non-inflammatory CNS diseases group. The results showed the positive rate of OCB between different gender, age, duration and recrudescence times in MS patients were no marked difference; but there was significant difference between activity and none activity stage, activity stage was significantly higher than none activity stage. The analysis of OCB types results indicated that the positive rate of OCB 2nd type in MS group (51.5%) was highest, and significantly higher than inflammatory CNS diseases group (3.1%); The positive rate of OCB 3rd type were respectively 18.8% and 12.5% in GBS and inflammatory CNS diseases, there was no obvious difference between them. The positive rate of OCB 3rd type in MS group was low, accounting for 6.1%. The positive rate of OCB 4th type was 37.5% in GBS group which was significantly higher than other CNS diseases. This study didn't detected OCB 5th type. The CSF IgG/CSF TP ratios compared in different OCB types were significantly different, the CSF IgG/CSF TP ratio in OCB-negative patients were lowest, followed by were OCB 2nd and OCB 4th type patients, OCB 3rd type patients were highest. The sensitivity and specificity of OCB 2nd type in the diagnosis of MS were respectively 51.5% and 98.7%, the positive predictive value and negative predictive value were respectively 94.4% and 82.6%; The sensitivity and specificity of OCB 3rd type in the diagnosis of MS were respectively 6.1% and 89.6%, the positive predictive value and negative predictive value were respectively 20% and 69%; The sensitivity and specificity of CSF IgG/CSF TP ratio in the diagnosis of MS were respectively 33.4% and 44.2%, the positive predictive value and negative predictive value were respectively 20.4% and 60.7%.This research demonstrated that detection of OCB has particular value to the auxiliary diagnosis of MS and GBS and has reference value to the distinguish diagnosis of inflammatory and non-inflammatory CNS diseases. OCB types have a certain correlation to CNS diseases, analyzing OCB types was helpful to the diagnosis of CNS diseases. Although the sensitivity of OCB to diagnosis MS was not high, the specificity was very high, therefore OCB has an important clinical value to the diagnosis of MS. To Sum up, OCB has important value to the diagnosis and distinguish diagnosis of CNS diseases, it was required to analysis the clinical presentation and other inspections comprehensively.