Immunofluorescence staining patterns in skeletal muscle using serum of myasthenic patients and normal controls

Using indirect immunofluorescent tests upon the sera of patients with myasthenia gravis and of normal subjects, two types of staining pattern are found. The first, A band staining, is seen only with myasthenic sera. The second, or `I band' pattern has not previously been described and is seen in an equal proportion of normal controls and of myasthenic patients. `I band' staining is a possible source of confusion in immunofluorescent tests for muscle antibody.