Lack of both spinal fluid oligoclonal bands and complement 4A protein in an MS patient

We report the case of a multiple sclerosis (MS) patient without oligoclonal bands (OCB) in three cerebrospinal fluid samples. Restriction fragment length polymorphism analysis of Class 3 genes with radiolabelled specific cDNA probes showed a homozygous deletion of the complement 4A (C4A) genes. Consequent lack of C4A protein can alter the development of humoral immune response probably preventing OCB production. Our observation may suggest a link between a rare immunogenetic pattern and the absence of OCB in MS.