Prediction of neonatal hyperthyroidism in infants born to mothers with Graves disease.

OBJECTIVE: To determine whether determinations of thyrotropin-receptor antibody (TRAb) levels in newborn infants of women with Graves disease would predict which infants will have hyperthyroidism. METHODS: The TRAb levels, assayed in the sera of 14 infants born to 14 women with Graves disease, were measured sequentially in the infants with hyperthyroidism during the course of antithyroid medication therapy. RESULTS: Seven infants had TRAb values less than 0.15 and remained euthyroid. In seven infants whose initial TRAb values were more than 0.25 (range, 0.48 to 0.88), clinical and biochemical signs of hyperthyroidism developed. The infants were treated with antithyroid medication until day 57 to day 123 of life. Therapy was discontinued when the infants were free of symptoms and when serum thyroxine and triiodothyronine and free thyroxine levels remained normal during therapy with decreasing doses of antithyroid medication. When the medication was discontinued, TRAb values were less than 0.20. CONCLUSIONS: Infants born to mothers with Graves disease with initial TRAb values less than 0.15 remained euthyroid. The TRAb values greater than 0.25 were associated with the development of neonatal hyperthyroidism. During treatment of neonatal hyperthyroidism, TRAb values less than 0.20 may be helpful in deciding when to withdraw antithyroid medication.

Detection of human growth hormone receptors on IM-9 cells and peripheral blood mononuclear cell subsets by flow cytometry: correlation with growth hormone-binding protein levels.

We have developed a method using flow cytometry to identify fluorescein-conjugated GH receptors (GHR) on IM-9 lymphocytes and circulating peripheral blood mononuclear cell subsets. Binding to IM-9 cells and peripheral blood mononuclear cells was concentration dependent and could be competitively blocked by the addition of unlabeled human GH, but not by the addition of rat or bovine GH or human insulin or PRL. Using two-color flow cytometric analysis, fluorescein-conjugated human GHR were readily detected on more than 90% of B lymphocytes and monocytes, but only variably on T lymphocytes. B Lymphocytes and monocytes had approximately 6000 GHR/cell. Using two-color flow cytometry, we identified GHR on circulating B lymphocytes in subjects with GH deficiency (n = 9), precocious puberty (n = 6), and Turner syndrome (n = 5) and in seven subjects with miscellaneous disorders, including familial short stature, bone dysplasia, Crohn disease, congenital adrenal hyperplasia, and acromegaly. The percentage of B lymphocytes expressing GHR in subjects with GH deficiency (mean +/- SD, 95 +/- 9%), precocious puberty (91 +/- 15%), and Turner syndrome (84 +/- 15%) was not different from that in normal volunteers (90 +/- 12%; n = 14). In 10 subjects, serum GH-binding protein levels were assayed simultaneously with B lymphocyte GHR. GH-binding protein was normal in all (mean, 1255 pmol/L; range, 773-1809). There was a good correlation between GHR expression on B lymphocytes and GH-binding protein levels (r = 0.75; P = 0.01). We postulate that GHR found on circulating B lymphocytes may contribute to the pool of receptors identified in serum as GH-binding proteins. Two-color flow cytometry appears to be an effective method for the detection of GHR on circulating peripheral blood mononuclear cell subsets. The evaluation of GHR on circulating B lymphocytes may prove to be a useful means of evaluating GH-GHR interactions in subjects with growth disorders.

46,XX pure gonadal dysgenesis with growth hormone deficiency and impaired 3 beta-hydroxysteroid dehydrogenase activity.

Patients with 46,XX pure gonadal dysgenesis generally are of normal stature and have less than usual amounts of pubic and axillary hair. We report on a patient who presented at age 11.9 years with short stature, absence of breast development, and excessive pubic hair. Her karyotype in leukocytes, fibroblasts, and streak gonad was 46,XX. The patient was diagnosed as having growth hormone deficiency. Elevated ACTH stimulated levels of 17-hydroxypregnenolone and dehydroepiandrosterone and elevated ACTH stimulated ratio of 17-hydroxypregnenolone to 17-hydroxyprogesterone suggested inadequate adrenal 3 beta-hydroxysteroid dehydrogenase activity. Treatment with growth hormone resulted in improvement in growth velocity and replacement with estrogen in feminization. We suggest that the finding of short stature in patients with 46,XX pure gonadal dysgenesis should not be attributed to the syndrome, but rather requires investigation for possible growth hormone deficiency. The poor growth of our patient prior to growth hormone replacement implies that dehydroepiandrosterone, unlike testosterone and estrogen, is ineffective in promoting linear growth in the absence of adequate growth hormone.

Immune functions during treatment of growth hormone-deficient children with biosynthetic human growth hormone.

Immune functions, including cell surface markers, interleukin-2 receptor levels and responses of lymphocytes to mitogenic stimulation were evaluated in seven growth hormone deficient children ages 4-15 years, during treatment with biosynthetically derived human growth hormone. Treatment resulted in a decrease in % B cells and in % T total cells and also decreases in most individual patients' mitogen responses and interleukin-2 receptor levels. Most of the changes noted were transient and similar to those previously demonstrated during pituitary-derived human growth hormone treatment. Although not resulting in overt clinical manifestations in our patients, we think that potential interactions between growth hormone and immune functions need to be considered by physicians treating children with growth hormone.