Reduced serum 25-hydroxyvitamin D concentration and disordered mineral metabolism in patients with cystic fibrosis.

Vitamin D and mineral metabolism were studied in 21 adolescents and young adults with cystic fibrosis and the results were compared to those in 21 matched controls. All CF patients had been maintained on standard multivitamin supplements in combination with pancreatic enzyme replacement. Despite this supplementation, relative to control subjects the CF patients had a 36% reduction in serum 25-hydroxyvitamin D concentration, a slight but significant reduction in serum calcium concentration, evidence of calcium malabsorption with secondary hyperparathyroidism, and a 14% decrease in bone mass measured by the photon absorption technique. Currently accepted modes of pancreatic enzyme replacement and vitamin D supplementation are often inadequate to maintain normal mineral homeostasis in CF patients; additional measurements may be required to reduce the risk of clinically significant osteopenia concomitant with prolonged survival in CF.

Successful transplantation of the thymus in Nezelof's syndrome.

A 6-month-old girl with congenital thymic dysplasia or Nezelof's syndrome (lack of T cell function and normal levels of immunoglobulins) was given a transplant of a human thymus gland from a 14-week-old fetus and is surviving 36 months after transplant. Her clinical condition is the principal index of the success of the transplant since most in vitro and in vivo data indicate a full immunologic restoration has not been achieved. However, the number of E-rosettes in the peripheral blood has increased, the number of surface immunoglobulin-bearing cells has decreased, but there is little improvement in mitogen responsitivity. Immunoglobulin levels have increased with age, but there is no demonstrable specific antibody activity. Nevertheless, she remains free of infection, living in an unprotected environment.