Transforming growth factor beta 1 (TGF beta 1) is a regulator of cell proliferation and differentiation. Using a mouse peritoneal cell-derived mast cell culture system, we investigated the effects of TGF beta 1 on mast cell proliferation. TGF beta 1 inhibited IL-3- and IL-4-dependent connective tissue-type mast cell proliferation. The effect was concentration dependent: 50% inhibition was observed with 1.0 ng/ml TGF beta 1 and the maximal inhibitory effect (no proliferation), was observed with 10 ng/ml. Flow cytometric analysis suggested that the inhibitory effect of TGF beta 1 was due to blocking of both G1 and G2 phases. Both control and TGF beta 1-treated mast cells showed similar histamine release induced by the calcium ionophore, A23187. TGF beta 1 seems to be an important negative regulator of connective tissue-type mast cell proliferation with apparently no appreciable effect on mast cell function.

We present a case of skin metastasis from follicular thyroid carcinoma which developed on the scalp of a 72-year-old man. The lesion was noticed 1 month after a surgical excision of the primary thyroid carcinoma and gradually enlarged during the past 11 months. A biopsy from the nodule showed mostly well-differentiated thyriod follicular structures with colloid material. Tumor cells showed mild variation of nuclear size and shape in almost all areas. We performed immunohistochemistry using antithyroglobulin antibody, which established the diagnosis of a metastatic lesion from thyroid follicular carcinoma. Total thyroidectomy and I radiotherapy were performed. No further metastasis has been discovered during the last 18 months.

Using mouse peritoneal mast cells, we investigated the effects of 1 alpha,25-dihydroxyvitamin D3 (calcitriol) on mast cell proliferation and histamine release. Calcitriol did not affect IL-3/IL-4-dependent mast cell proliferation, but it selectively inhibited stem cell factor-dependent mast cell proliferation and colony formation. Immunohistochemical and immunoblot analyses revealed that calcitriol treatment reduced expression of purified peritoneal mast cell c-kit protein. Using a mast cell line, MC/9, both c-kit protein and c-kit mRNA transcript were seen to be reduced following calcitriol treatment. Calcitriol also reduced histamine release induced by calcium ionophore A23187. In contrast, anti-IgE antibody-dependent histamine release was not affected by calcitriol. Our results indicate that calcitriol inhibits mast cell proliferation and A23187-induced histamine release that might be associated with a decreased expression of c-kit receptor.

Murine mast cell proliferation and maturation are regulated by two distinct cytokines, interleukin-3 (IL-3) and the c-kit ligand, stem cell factor (SCF). In this study using cells of the mouse mast cell line, MC/9, the effects of two immunosuppressants, FK506 and cyclosporin A (CsA), were investigated. Withdrawal of IL-3 from the culture medium resulted in loss of viability of MC/9 cells. The addition of SCF in the absence of IL-3 maintained MC/9 cell survival but no cell proliferation was detected. The combined addition of IL-3 and SCF to the culture medium resulted in a more marked MC/9 cell proliferation than the addition of IL-3 alone. FK506 and CsA inhibited the SCF-dependent, but not the IL-3 dependent, stimulatory effects on MC/9 cell proliferation/survival. Apoptotic changes were analyzed using fluorescent staining with acridine orange and DNA electrophoresis. FK506 and CsA inhibited the SCF-dependent rescue effect from apoptosis. Flow cytometry showed that FK506 and CsA did not affect IL-3 receptor expression. However, immunoblot and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses indicated that c-kit protein and c-kit mRNA transcripts were increased following the FK506 and CsA treatments in the presence of IL-3. In addition, MC/9 cells pretreated with FK506 or CsA showed an increased adhesiveness to NIH/3T3 cells that express membrane-bound SCF. Neither FK506 nor CsA affected c-kit tyrosine phosphorylation or MAP kinase nuclear translocation of MC/9 cells following SCF stimulation. These results indicate that FK506 and CsA, while inducing c-kit of MC/9 cells, selectively inhibit the SCF-dependent stimulatory effects on MC/9 cell proliferation/survival by a mechanism independent of, or at point(s) distal to, the c-kit-MAP kinase pathway.

Anogenital PD was more frequently associated with epidermal hyperplasia than axillary PD. Fibroepitheliomatous hyperplasia may be induced by the altered stroma associated with PD.