SEARCH:   Advanced

Blood, 1 May 2006, Vol. 107, No. 9, pp. 3426. This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Mohandas, N. Search for Related Content PubMed Articles by Mohandas, N. Related Collections Related Article in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  RED CELLS Comment on Buffet et al, page 3745 Of mice and men: the voracious spleen Narla Mohandas NEW YORK BLOOD CENTER Over the years, physiological studies have provided many insights into the function of the spleen, and now, in this issue of Blood, Buffet and colleagues describe significant new mechanistic insights into clearance of parasitized human red cells by the spleen. In ancient times the spleen was an organ of mystery, held to be the seat of ill humors. Two millennia after Aristotle and Hippocrates, in 1885, a physiologic function was finally ascribed to the spleen: it was a filter, which eliminated unwanted particles from the blood.1 It has long been established that the spleen is a highly efficient device for sequestering abnormal red cells, such as hereditary spherocytes or elliptocytes. Splenectomy, in consequence, prolongs the life of such cells and is an indicated measure in the treatment of patients suffering from such conditions. In malarial infections, on the other hand, the spleen serves the useful function of ridding the bloodstream of parasitized cells,2 and if it is removed, parasitemia levels are apt to rise and the symptoms worsen.3 But to what extent and in what circumstances the spleen exercises its beneficial function have been far from clear. Our ignorance has been compounded by the profound differences in structure and physiology between the human spleen and that of laboratory animals, such as mice. An ingenious study with wide implications, reported in this issue of the journal, now sheds new light on the subject. Buffet and colleagues have devised an ex vivo experimental system using human spleens that allows them to follow the time course of clearance of parasite-infected red cells. The authors show that 95% of Plasmodium falciparum–infected cells, preexposed to the antimalarial drug artesunate, are cleared from the perfusate in 2 hours and that more than 90% of these cells are retained and processed in the red pulp of the spleen. What are the implications of these findings? One is that the "pitting" action of the spleen in clearing the intracellular parasites from the infected red cells is now unequivocally established (see figure). But in the broader context, the new experimental system affords a general route to the study of physiologic and pathologic mechanisms of human spleen function in the remodeling of reticulocytes and in clearing types of abnormal red cells from the circulation. "You shall," as Shakespeare has it, "digest the venom of your spleen" (Julius Caesar, act 4, scene 3, line 53). View larger version (82K): [in this window] [in a new window]   Pitting of dead parasite remnants from the infected red cells during passage from the splenic cord to sinus lumen. See the complete figure in the article beginning on page 3745.   References Jacobsen CT, Shurin SB. Disorders of the spleen. In: Handin RI, Lux SE, Stossel TP, eds. Blood: Principles and Practice of Hematology. 2nd ed. Lippincott Williams & Wilkins; 2003: 649-671. Chotivanich K, Udomsangpetch R, McGready R, et al. Central role of spleen in malaria parasite clearance. J Infect Dis. 2002;185: 1538-1541.[CrossRef][Medline] [Order article via Infotrieve] Demar M, Legrand E, Hommel D, Esterre P, Carme B. Plasmodium falciparum malaria in splenectomized patients: two case reports in French Guiana and a literature review. Am J Trop Med Hyg. 2004;71: 290-293.[Abstract/Free Full Text] CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Article in Blood Online: Ex vivo perfusion of human spleens maintains clearing and processing functions Pierre A. Buffet, Geneviève Milon, Valentine Brousse, Jean-Michel Correas, Bertrand Dousset, Anne Couvelard, Reza Kianmanesh, Olivier Farges, Alain Sauvanet, François Paye, Marie-Noëlle Ungeheuer, Catherine Ottone, Huot Khun, Laurence Fiette, Ghislaine Guigon, Michel Huerre, Odile Mercereau-Puijalon, and Peter H. David Blood 2006 107: 3745-3752. [Abstract] [Full Text] [PDF] This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Mohandas, N. Search for Related Content PubMed Articles by Mohandas, N. Related Collections Related Article in Blood Online Social Bookmarking                   What's this?

	Copyright © 2006 by American Society of Hematology         Online ISSN: 1528-0020