[Analysis of the cerebrospinal fluid by isoelectrofocusing on agarose in multiple sclerosis]

Intrathecal synthesis of immunoglobulins can be proved by means of two methods: quantitatively by immunoglobulins titration in CSF, the results expressed with several ratios; qualitatively by demonstration of oligoclonal distribution of gammaglobulins. IEF is the most sensitive of the qualitative methods. From a technical point of view Agarose Isoelectrofocusing seems to be a better method than polyacrylamide isoelectrofocusing and permits, when the interpretation is difficult, immunofixation into the gel. The authors report the results of a comparative study between the evaluation of the IgG Index and agarose isoelectrofocusing of 281 CSF divided into 113 CSF from patients with Multiple Sclerosis (MS) and 168 CSF from patients with other neurological diseases (OND). Sensitivity of IEF was higher than IgG index to prove intrathecal IgG synthesis: in the group of patients with MS, 91 p. 100 of CSF were abnormal instead of 72 p. 100 of IgG Index. In the group of patients with OND, abnormalities in IEF were low (5 p. 100) but the number of inflammatory diseases was poor. These results were similar with the findings of many authors using the same methods. In our opinion, IEF is the best technique which a specialized laboratory can use in routine to prove an immunoglobulin intrathecal synthesis.