title: Elevated platelet counts and thrombocytosis in erythema nodosum leprosum.
abstract: Changes in peripheral blood platelet counts associated with the onset of symptomatic erythema nodosum leprosum (ENL) were studied by comparing, in each patient, the value obtained on the day thalidomide therapy commenced with the average of the three preceding values. In the 11 patients studied, the mean platelet count rose from 235 to 322 x 10(3)/mm3, p < 0.001. In 3, the platelet count was above the normal limit, qualifying as thrombocytosis, in 7 the rise was appreciable, and in 2 it was negligible. In the 3 patients studied 1-2 weeks after beginning thalidomide, the mean count was 414 x 10(3)/mm3. Counts obtained after 3 or more weeks of thalidomide therapy were within normal limits. This study provided no direct evidence as to the mechanism responsible for the elevated platelet count, but mediation by interleukin-6 (IL-6) was concluded to be an attractive hypothesis, consistent with prior studies of IL-6 in reactive thrombocytosis and of IL-6 in ENL.
authors.affiliation: Division of Dermatology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA. rea@hsc.usc.edu
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Rea
mesh_terms: D000328:Adult; D004893:Erythema Nodosum / Q000097:blood* / Q000139:chemically induced; D005260:Female; D006801:Humans; D007917:Leprostatic Agents / Q000009:adverse effects / Q000627:therapeutic use; D015440:Leprosy, Lepromatous / Q000097:blood* / Q000188:drug therapy; D008297:Male; D008800:Mexico / Q000208:ethnology; D008875:Middle Aged; D010679:Philippines / Q000208:ethnology; D010976:Platelet Count; D012189:Retrospective Studies; D013792:Thalidomide / Q000009:adverse effects / Q000627:therapeutic use; D013922:Thrombocytosis / Q000097:blood* / Q000139:chemically induced; D014481:United States
chemical_list: D007917:Leprostatic Agents; D013792:Thalidomide