concanavalin-a and Alopecia

The physiopathological role of androgen binding proteins in male pattern baldness (MPB) has been studied by using tritiated dihydrotestosterone (DHT) and methyltrienolone (R 1881) as ligands. DHT binding in bald scalp from subjects suffering from MPB is high (53 +/- 12 fmol/mg protein) in cytosol obtained from bald areas, being undetectable in hairy areas from the same subject. Since methyltrienolone does not bind in bald scalp cytosol, there must be no specific DHT receptor in this material. Several kinetic and molecular parameters of DHT binding in bald scalp cytosol and serum were similar in both samples. Only the association rate constant (k+1) was significantly higher in serum (8.8 X 10(6) M-1 min-1) than in cytosol (3.08 X 10(6) M-1 min-1). DHT binding in serum as well as the evaluation of plasma contamination in the skin samples (by nephelometric analysis) strongly suggests that DHT binding in skin cytosol is merely due to the presence of contaminating SHBG but it does not explain the lack of DHT binding in non bald areas. Thus, the possibility arises of there being a specific mechanism for the uptake of the plasmatic testosterone SHBG-complex taking place only in the hypertrophic sebaceous gland as well as the existence of active T metabolites other than DHT, probably 3 beta-androstanediol.

Topics: Alopecia; Blood Proteins; Centrifugation, Density Gradient; Concanavalin A; Cytosol; Dihydrotestosterone; Estrenes; Humans; Kinetics; Male; Metribolone; Radioligand Assay; Receptors, Androgen; Sebaceous Glands; Sepharose; Testosterone

Several values of immunologic function were studied and correlated with disease activity and extent in 14 patients with alopecia areata, alopecia totalis, or alopecia universalis and in a concurrently studied age- and sex-matched control group. As compared with the control group, the patients showed a significantly increased incidence of autoantibody formation, increased concanavalin A-induced suppression of the normal lymphocyte response to mitogens, an increased proportion of suppressor-cytotoxic cells in the peripheral blood, and a decrease in the absolute B-cell count. Absolute total T-cell counts, quantitative serum immunoglobulin determinations, and lymphocyte proliferation after exposure to the mitogens--concanavalin A, phytohemagglutinin, and pokeweed--and to tetanus antigen were comparable for both groups. Neither the percentage of concanavalin A-induced suppression of the normal lymphocyte response to mitogens nor the helper-suppressor ratio correlated significantly with the extent of hair loss. However, patients, particularly those who demonstrated spontaneous regrowth of hair, had increased concanavalin A-induced suppression in conjunction with an increase in the proportion of peripheral suppressor cells.

Topics: Adolescent; Adult; Alopecia; Alopecia Areata; Autoantibodies; B-Lymphocytes; Concanavalin A; Female; Humans; Leukocyte Count; Lymphocyte Activation; Male; Middle Aged; T-Lymphocytes, Regulatory