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Year : 2009  |  Volume : 52  |  Issue : 2  |  Page : 289-290
Emperipolesis in immune thrombocytopenic purpura

Section of Hematology, Department of Pediatrics, Faculty of Medicine, Gazi University, Besevler, Ankara, Turkey

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How to cite this article:
Aslan D. Emperipolesis in immune thrombocytopenic purpura. Indian J Pathol Microbiol 2009;52:289-90

How to cite this URL:
Aslan D. Emperipolesis in immune thrombocytopenic purpura. Indian J Pathol Microbiol [serial online] 2009 [cited 2022 May 19];52:289-90. Available from: https://www.ijpmonline.org/text.asp?2009/52/2/289/48956


We read the article by Sharma and Rawat with great excitement. [1] The association of emperipolesis and immune thrombocytopenic purpura (ITP) is interesting. Here, our recent experience and opinion related to emperipolesis is presented.

Historically, the term emperipolesis was proposed by Humble et al. in 1956 to describe "the temporary presence of one cell within another's cytoplasm." In clinical use, emperipolesis is the penetration of hematopoietic cells into the cytoplasm of megakaryocytes. Emperipolesis differs from phagocytosis because the engulfed cells remain viable and can ultimately exit from the engulfing cell. The pathophysiological mechanism is still unclear and various theories have been postulated, including injured and/or altered megakaryocytes. Despite the striking morphological appearance of megakaryocyte emperiopolesis, clinical significance is yet uncertain. It has been observed to occur under a variety of clinical conditions. ITP, as also observed by the authors, is one of these clinical conditions [1],[2] and differs from the others in that it is in itself a megakaryocyte disease. Therefore, it may be speculated that the presence of emperipolesis in ITP may have clinical importance.

Recently, we had the opportunity to study three newly diagnosed ITP cases with emperipolesis. Megakaryocytes were extensively involved in two cases (35-40%) whereas in the other emperipolesis was detected in occasional megakaryocytes (5%). All cell types were found to be engulfed. No other morphological abnormalities of megakaryocytes could be seen by light microscopy. All three patients were treated with a similar protocol (intravenous immunoglobulin G [IVIG] 800mg/kg, single dose). The case with slight emperipolesis responded well to treatment. The number of platelets increased to the normal level and maintained this value. The cases with extensive emperipolesis, however, responded weakly. The platelet number reached a moderate level and then decreased soon after. The platelet counts still remain low at 9 months after diagnosis in these two cases (50.000/mm 3 and 20.000/mm 3 ).

Our experience, taking into consideration the previous two reports, [1],[2] has led us to consider that emperipolesis might be a pathologic phenomenon of ITP and may perhaps be associated with decreased response to treatment and chronicity. It is known that childhood ITP is a self-limited disease resolving within 6 months and 10% of the pediatric cases are chronic. Considering the lack of a laboratory finding showing the tendency for chronicity, a careful examination of bone marrow aspiration at diagnosis for emperipolesis may have clinical importance. In ITP, chronic form means no properly responding megakaryocytes after acute incident; in another word, megakaryocyte dysfunction. Although platelets are destroyed by antibodies, it is the response of megakaryocytes that provides resolution in acute ITP. On the other hand, emperipolesis could be an indication of megakaryocyte injury as well. Recent findings illustrate that autoantibodies play a role not only in platelet destruction but also in megakaryocyte alterations and abnormal megakaryocytopoiesis in patients with ITP. [3],[4] It may be reasonable to state that megakaryocyte damage may be severe in some patients leading to insufficient production of platelets. Thus, "chronic cases" may be identified with an increased degree of emperipolesis at diagnosis. There is growing evidence suggesting that impaired thrombopoiesis is of importance in the pathogenesis of chronic ITP. [5] Moreover, megakaryocyte alterations causing impaired thrombopoiesis is reversed with treatment with either prednisone or IVIG. [4] Unfortunately, follow-up bone marrow aspiration was not performed in our patients because of the reluctance of the families. Therefore, the outcome of emperipolesis in the marrow could not be determined.

In summary, based on our experience along with the article published in your journal, it may be suggested that careful examination of the bone marrow at diagnosis may be of importance to assess the prognosis of thrombocytopenia. Retrospective marrow examination for emperipolesis and chart review including patient outcome and presence of antiplatelet antibodies may be useful to attain large numbers of patients.

   References Top

1.Sharma S, Rawat A. Increased emperipolesis in megakaryocytes in a case of idiopathic thrombocytopenic purpura. Indian J Pathol Microbiol 2006;49:631.  Back to cited text no. 1  [PUBMED]  Medknow Journal
2.Hu T, Shi XD, Feng YL, Liu R, Li JH, Wang TY, et al . Study on bone marrow megakaryocytes in children patients with idiopathic thrombocytopenic purpura. Zhongguo Shi Yan Xue Ye Xue Za Zhi 2004;12:480-3.  Back to cited text no. 2  [PUBMED]  
3.Houwerzijl EJ, Blom NR, van der Want JJ, Vellenga E, de Wolf JT. ­Megakaryocytic dysfunction in myelodysplastic syndromes and ­idiopathic thrombocytopenic purpura is in part due to different forms of cell death. Leukemia 2006;20:1937-42.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]
4.Wang L, Li Y, Hou M. Idiopathic thrombocytopenic purpura and ­dysmegakaryocytopoiesis. Crit Rev Oncol Hematol 2007;64:83-9.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]
5.McMillan R. The pathogenesis of chronic immune thrombocytopenic purpura. Semin Hematol 2007;44:S3-11.  Back to cited text no. 5  [PUBMED]  [FULLTEXT]

Correspondence Address:
Deniz Aslan
Hematology Section, Department of Pediatrics, Faculty of Medicine, Gazi University, Besevler, Ankara
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.48956

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