Capping of lymphocytes in patients and carriers of Duchenne muscular dystrophy.

Recent results showed that Duchenne muscular dystrophy is probably associated with a generalized membrane defect. The capping phenomenon in lymphocytes indicates normal intramembrane protein mobility and disturbances of this phenomenon are is believed to reflect membrane alterations. We have investigated capping in lymphocytes from 19 patients with Duchenne muscular dystrophy, 13 carriers, 8 patients' sisters, 14 patients' aunts and 52 normal controls. All 19 patients showed a reduction in capping both with fluorescein conjugated polyvalent goat antiserum (mean +/- SD = 18.5 +/- 5.1% and with fluorescein labeled Concanavalin A (mean +/- SD = 10.8 +/- 3.1%) as compared to controls. Normal persons (n = 52) have a mean of 50.2 +/- 9.9% (SD) capping with polyvalent anti-immunoglobulin (range: 32--72.5%) and 25.6 +/- 3.6% with F-Con A (range: 18.5--31.5%). 12 of the 13 mothers, as well as 5 of the 8 patients' sisters, also exhibited decreased lymphocyte capping to the same extent as the patients. Creatine kinase activity (CK) was elevated only in 4 mothers and 2 of the sisters. Our results indicate that this method might be of value in detecting carriers and can yield less false negative results as the CK-activity test.