CD79A and myeloid sarcoma: We observed a serum IgA concentration over the n.r in 3/151 MS patients, who had an IgA level in the CSF within the n.r. 9/53 patients from the control group showed a serum IgA concentration higher than the n.r, but only 4 had an IgA concentration in CSF above the n.r. Low serum IgA concentration (< 20 mg/mL) was detected in 2/53 individuals from the control group and in 5/151 MS patients, all of them showed an IgA concentration in CSF lower than the n.r.