title: In vivo and in vitro effects of doxycycline on leucocyte membrane receptors.
abstract: Tetracyclines, particularly doxycycline, have adverse effects on granulocyte function in vitro. We have examined the effects of doxycycline on membrane receptors for IgG (Fc gamma-R) and C3b (C3b-R) on granulocytes and lymphocytes, as well as on the sheep erythrocyte receptor (E-R) on T lymphocytes. Acne patients given doxycycline orally had a lower percentage of Fc gamma-R positive granulocytes (57%) than before treatment (80%) or compared to healthy controls (81%). Following in vitro doxycycline incubation, normal granulocytes showed decreased levels of Fc gamma-R positive cells. This effect was counteracted by the addition of magnesium during incubation. The deleterious effect of doxycycline on granulocyte functions may be due to decreased levels of Fc gamma-R bearing granulocytes. Doxycycline in vivo or in vitro had no significant effect on the proportion of C3b-R bearing granulocytes or lymphocytes or the T lymphocyte percentage. After in vitro irradiation with light at 340-380 nm, however, both granulocytes and lymphocytes preincubated with doxycycline showed up to 50% decrease in Fc gamma-R bearing cells, while control cells without doxycycline were unaffected.
mesh_terms: D000152:Acne Vulgaris / Q000188:drug therapy / Q000276:immunology; D004318:Doxycycline / Q000494:pharmacology* / Q000627:therapeutic use; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000276:immunology*; D011951:Receptors, Complement / Q000187:drug effects* / Q000528:radiation effects; D017463:Receptors, Complement 3b; D011961:Receptors, Fc / Q000187:drug effects* / Q000528:radiation effects; D017452:Receptors, IgG; D012397:Rosette Formation; D014466:Ultraviolet Rays
chemical_list: D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D011961:Receptors, Fc; D017452:Receptors, IgG; D004318:Doxycycline