British Journal of Haematology, 1992, 82, 173-179

Correspondence ANTIPLATELET ANTIBODIES IN IDIOPATHIC THROMBOCYTOPENIC PURPURA Although the results of Kazemi et al (1991) are somewhat supportive of our findings it could be concluded that the method of Handin & Stossel (1974) is more appropriate for the detection of APA in ITP cases in relapse or in remission even though the two methods are very similar in principle.

I have read with interest the recent article entitled ‘An in vitro direct chemiluminescence assay for assessment of plateletbound antibody in thrombocytopenic patients’ (Kazemi et al. 1991). The authors, without looking at our study (Ozsoylu et al, 1977). stated that ‘the interaction between phagocytes and autologous autosensitized platelets was not measured’. In our study it was looked for in vivo but could not be found (~zsoyluet al, 1977). I would also l i e to bring to the authors attention that by using the method described by Handel & Stossel (1974) we were able to detect antiplatelet antibodies (APA) in all 103 patients with acute idiopathic thrombocytopenic purpura (ITP) and 46 patients with chronic ITP. These antibodies could also be found during remission in all children who had had acute (100 cases) and chronic (32 cases) ITP, although the level was markedly lower than that during the thrombocytopenic period. Moreover, a rise in the APA level was seen during relapse in four chronic and two acute ITP patients. A decrease of APA was also shown by two out of four children who had re-entered remission after relapsed chronic ITP (c)zsoylu et aI, 1991). APA were not found in any of 126 control sera obtained from 67 haematologically normal individuals and 59 thrombocytopenic patients of whom 28 had acute leukaemia. 10 acquired aplastic anaemia, 10 Fanconi’s anaemia and 11 sepsis with thrombocytopenia ((lzsoylu et al. 1991). The persistence of APA during remission in cases of acute and chronic ITP, previously reported by us ((lzsoylu et al, 1976), explains the shorter survival of platelets in these children.

Department of Paediatrics, Hacettepe University Faculty of Medicine, Hacettepe Childrens Hospital, Ankara 06100, Turkey

SINASIC~ZSOYLU

REFERENCES Handin, R.I. & Stossel,T.P. (1974) Phagocytosis of antibody-coated platelets by human granulocytes. New England Journal of Medicine. 290, 989-993.

Kazemi, A., Singh, A.K. & Slater, N.E.P. (1991) An in vitro direct chemiluminescence assay for assessment of platelet-bound antibody in thrombocytopenic patients. British Journalof Haematology. 79, 624-627.

&soylu, S., Allahverdi, H.. Laleli, Y. & Pirnar. A. (1976) Platelet survival in childhood idiopathic thrombocytopenic purpura in remission. Journal ofpediatrics, 89, 388-390. ozsoylu. S., Karabent. A., Irken, G. &Turner,M. (1991)Antiplatelet antibodies in childhood idiopathic thrombocytopenic purpura. American Journal of Hematology, 36, 82-8 5. ozsoylu, S.. SavaS, G. & Laleli, Y. (1977) Quantitative nitroblue tetrazolium in idiopathic thrombocytopenic purpura. Journal of Pediatrics, 91, 1024-102 5.

EXPRESSION OF MYELOID ASSOCIATED ANTIGENS IN CHRONIC LYMPHOCYTIC LEUKAEMIA firmed and extended by Morabito et al (1987) which correlated the expression of CD13 and of other myelomonocytic antigens, including CD33, CD14 and CD15, on B-CLL with interleukin-1 (IL-1) secretion by leukaemic lymphocytes. Following these initial reports we described the expression of CD13. CD14 and CD33 on B-CLL cells during the I11 (Del Vecchio et al, 1987) and IV (Pinto et al, 1989) workshops on leucocyte differentiation antigen by analysing leukaemic lymphocytes from the peripheral blood, bone marrow and lymph nodes by single or two-colour immunofluorescence and immunohistochemistry (Pinto et al, 1991, 1992). To date, more than 350 B-CLL samples have been analysed for CD13 expression in different series (Table I) by utilizing various monoclonal antibodies and all studies indicated that about 20-30% of B-CLLs actually express CD13 determinants either alone or with other myelomonocytic antigens such as CD14, CD33 and CD15. In a single study

Kawamata et aI (1992) have described in a recent issue of this journal a case of B-cell chronic lymphocytic leukaemia (B-CLL) characterized by the expression of the myeloidassociated antigen CD13 (aminopeptidase N) as shown by two-colour immunofluorescence.The authors state that their patient may represent ‘the first reported case of truly myeloidassociated antigen positive CLL’ since ‘no case of myeloidassociated antigen positive CLL has been reported’ previously. While acknowledging that the patient described by Kawamata et af may actually represent the first case described in Japan or by Japanese authors, we have to point out that the expression of CD13 on B-CLL cells has been previously detected, reported and extensively analysed by several other investigators including our research group. We first identified (Pinto et al, 1987) a subset of ‘classical’CDS-positive B-CLLs characterized by expression of CD13 and high levels of c-fos oncogene mRNA. These results were independently con-

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Antiplatelet antibodies in idiopathic thrombocytopenic purpura.

British Journal of Haematology, 1992, 82, 173-179 Correspondence ANTIPLATELET ANTIBODIES IN IDIOPATHIC THROMBOCYTOPENIC PURPURA Although the results...
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