Letters and Correspondence 361

Fig. 1. Leukemic cells with clover leaf shaped nuclei. Wright-Giemsa stain. Peripheral blood (original magnification x400).

nuclei. We report here a patient with chronic lymphocytic leukemia (CLL) whose lymphocytes showed “clover leaf’ nuclear morphology.

A 60-year-old Caucasian man was diagnosed to have CLL in 1976 when he presented with constitutional symptoms, generalized lymphadenopathy, and cranial nerve paralysis. Laboratory testing showed lymphocytosis (1 1.6 x 109/L) with many smudge cells, normal hemoglobin (1 16 g/L) and platelet count (250 X 109/L). The bone marrow showed extensive infiltra- tion by mature lymphocytes. He responded well to chlorambucil, pred- nisone, and radiotherapy and remained stable until 1992, when his disease became chlorambucil resistant, with progressive lymphocytosis (87.8 X 109/L) and well-maintained hemoglobin (1 11 g/L) and platelets (150 X 109/L). The lymphocytes were small (1C-15 pm), had a moderate amount of pale blue agranular cytoplasm, and 30-50% of them showed irregular nuclei with the “floret” or “mulbeny leaf‘ or “clover leaf” config- urations (Fig. l).Persistence of this abnormality was confined on three separate occasions, using fresh EDTA anticoagulated specimens. The im- munophenotype of the lymphocytes was in keeping with CLL (CD 45+, 19+, 20+ (dim), 5 + , HLA DR+ (dim), 23+, and kappa light chains+ (dim)). Epstein Barr virus, cytomegalovirus, HIV, and HTLVl serology were all negative. He responded to fludarabine and continues to remain stable. Twenty to 50% of the leukemic cells, however, still show clover leaf nuclei.

Lymphocytes with clover leaf nuclear abnormalities are characteristi- cally seen in the blood lymphocytes of patients with ATLL [ l ] and are considered pathognomonic [Z] for this condition. However, their diagnostic significance is diminished by occasional finding of similar cells in patients with B-lymphoproliferative disorders like CLL (our case), smokers’ poly- clonal lymphocytosis [3] and hairy cell leukemia [4], in patients with reactive lymphocytosis, e.g., infections with cytomegalovirus [ 5 ] , Epstein Barr virus [6], and Toxoplasma gondii [7], or as storage artifact in over- night blood samples [5]. Management and course of ATLL is different from any of the conditions described above. Awareness of limitations of clover leaf morphology, repeat testing under controlled laboratory conditions, appropriate serological testing, and immunophenotyping would help differ- entiate these conditions from ATLL.

KAREN M. HUHN BAKUL I. DAUL

SHELMN C. NAIMAN

NOEL A. BUSKARO Division of Hematopathology, Department of Pathology,

Division of Clinical Hematology, Depaftment of Medicine, Vancouver Hospital and Health Sciences Center, Vancouver, British Columbia, Canada

REFERENCES

1. Shimoyama M: Diagnostic criteria and classification of clinical subtypes of adult T-cell leukemia-lymphoma. Br J Haematol79428437, 1991.

2. Kamihira S, Atogami S, Sohda H, Momita S , Yamada Y, Tomonaga M: Signifi- cance of soluble interleukin-2 receptor levels for evaluation of the progression of adult T-cell leukemia. Cancer 73:2753-2758, 1994.

3. Gordon DS, Jones BM, Browning SW, Spira TJ, Lawrence DN. Persistent poly- clonal lymphocytosis of B lymphocytes. N Engl I Med 307:232-236, 1982.

4. Hanson CA, Ward PCJ, Schnitzer B: A multilobular variant of hairy cell leukemia with morphologic similarities to T-cell lymphoma. Amer J Surg Pathol 13:671- 679, 1989.

5. Teng TI, Chen RL, Wu TJ, Lin KH: Clover-leaf nucleus of atypical lymphocytes in CMV-mononucleosis syndrome: report of one case. Acta Paediatr Sin 31:379- 382, 1990.

6. Inque S: Clover leaf nucleus of atypical lymphocytes in infectious mononucleosis. Br J Haematol70:381-386, 1988.

7. Win N, Davies SC: Clover Leaf nuclei in atypical lymphocytes during acute Toxoplasma gondii infection. Clin Lab Haematol 12:lll-112, 1990.

Cell Adhesion Receptors on Neoplastic Plasma Cells

To the Edirort The paper of Yamagata et al. [ I ] reports the successful treatment of a case with plasma cell leukemia (PCL), moreover, the pheno-

362 Letters and Correspondence

and karyotype as well as the adhesion profile of the leukemic plasma cells are also presented [I]. Yamagata et al. conclude that “little is known about the expression of adhesion molecules in PCL. Further investigation of the biological characteristics of PCL is warranted.” Despite the undoubtedly existing contradictions, I think the accumulating knowledge about the ad- hesion profile of neoplastic plasma cells and some implications of the administered therapy deserve further comment.

The most interesting aspect of PCL is to explain the critical changes in cell-cell and cell-matrix contacts which unexpectedly allow the sessile neoplastic plasma cell to appear in the blood. Some years ago, we demon- strated that leukemic plasma cells adhered to endothelial venules, while in the same in vitro experimental setting, plasma cells isolated from the bone marrow (BM) of patients with multiple myeloma (MM) were unable to bind high endothelial venules [2]. Based on the findings, it seemed reasonable to explain the striking differences of blood vs. BM involvement in MM and PCL with the potential differences of the endothelial cell receptor profiles. Further reports on MM and PCL have revealed a variable pattern in the adhesion profile of neoplastic plasma cells, but a reliable comparison of these profiles is hampered by differences in the detection systems used in different laboratories. The CD54 (ICAM-I)/CD56 (N-CAM)/CD44 (H- CAM) positivity seemed to be the only consistent findings on neoplastic plasma cells. However, these findings were also challenged by the case report of Tsutani et al. [3], i.e., a case of MM transformed to PCL with a discordant CDI lalCD18 (LFA-I a- and P-chain)/lCAM-1 expression was presented. Namely, in the latter study, leukemic plasma cells from the blood were CD54 positive and negative for CDl ldCD18 while neoplastic cells from the infiltrating subcutaneous plasmocytoma showed a reverse pattern (CD54 negative CDI lalCD18 positive). Contradictory findings were communicated about the LFA-I a-chain (CDl la) expression, too, and even experiments on cells from the same MM-derived cell line (U-266, American Type Culture Collection) showed a diverse adhesion phenotype depending on the applied detection system 141. The efficiency of recogniz- ing multiple glycosylated isoforms of integrin a-chain by different anti- CDI l a monoclonal antibodies was also different [4,5]. Intriguingly, as it is cited in the paper of Yamagata et al. [l], the LFA-1 expression correlated well with the plasma cell proliferation in MM [ 5 ] , and an LFA-I/ICAM-I adhesion pathway between neoplastic plasma cells and lymphokine produc- ing BM stromal cells was envisaged. Some members of the VLA integrin series (CD49dICD29 and CD49eiCD29) were equally well expressed on BM and blood derived normal and malignant plasma cells as well [4]. Conclusively, although knowledge about the adhesion receptors of neoplas- tic plasma cells expands rapidly and gives explanation to some important cell-cell and cell-matrix interactions in the BM, it is still unable to explain the diverse in vitro endothelial binding activity of BM and PCL plasma cells [2].

The potential effect of interferon-cu (IFN-a) on the adhesion receptors of leukemic plasma cells might represent another remarkable aspect of Yama- @a et al., report 111. IFN-a may alter the expression and density of certain adhesion molecules (LFA-I, ICAM-I , L-selectin) on leukemic cells from hairy cell leukemia and chronic lymphocytic leukemia (9-CLL), and such changes may help to eliminate them from the circulation. Previous studies demonstrated that IFN-a induced an increased density of L-selectins (Leu-8, TQ1, LAM series, and LECAM-I) on B-CLL cells which was sufficient to result in an enhanced adherence to HEVs and immobilized L-selectin ligand analogs [ 6 ] . Although it is well known that activated B cells, plasma cells, and neoplastic cells from MM do not express L-selec- tins [41, it remains to be tested whether L-selectins and other adhesion molecules might be inducible on the surface of leukemic plasma cells. Concerning Yamagata et aL’s case, it should also be very interesting to see whether the tested adhesion molecules showed any change during the administration of the therapeutic regimen.

GVORGV CSANAKV Department of Pathology, University Medical School of Pecs, Pecs, Hungary

REFERENCES

1 . Yamagata N, Shimazaki C, Goto H, Hirata T, Ashihara E, Oku N, Inaha T, Fujita N, Nakagawa M: IgE plasma cell leukemia successfully treated with combination VAD (vincristine, doxoruhicin, dexamethosane) and MP (melphalan, prednisolon) followed by interferon-a. Am J Hematol45262-264, 1994.

2. Kalisz V, Pap T, Csanaky Gy, Kelknyi G: Endothelial cell receptors on leukemic plasma cells. Leukemia Res 13:863-868, 1989.

3. Tsutani H, Sugiyama T, Shimizu S, Iwasaki H, Ueda T, Ozaki K, Konda S, Nakamura T: Discordant LFA-1IICAM-I expression in a case of secondary plasma cell leukemia associated with subcutaneous plasmocytoma. Am J Hematol42:299- 304, 1993.

4. Kim I , Uchiyama H, Chauhan D, Anderson KC: Cell surface expression and functional significance of adhesion molecules on human myeloma-derived cell lines. Br J Haematol87:483493, 1994.

5 . Ashmann EJM, Lokhorst HM, Dekker AW, Bloem AC: Lymphocyte function- associated antigen-I expression on plasma cells correlates with tumor growth in multiple myeloma. Blood 79:2068-2075, 1992.

6. Csanaky G , Vass JA, Ocsovszki I , Milosevits I , Szomor A, Schmelczer M: Changes in adhesion molecule expression and function in B-cell chronic lympho- cytic leukaemia after in vitro interferon-a stimulation. Eur J Haematol 54:27-33, 1995.

Author’s Reply

TO the Editor: The letter by Dr. Csanaky addressed two important aspects about adhesion molecules in our case. First, leukemic plasma cells ex- pressed both LFA- 1 and ICAM-1 in our case. Second, adhesion molecules on the neoplastic plasma cells might be altered during the interferon ther- apy.

We have been examining expression of adhesion molecules on neoplastic plasma cells from 31 cases, including 3 cases with plasma cell leukemia (PCL) (in preparation). Among 3 PCL cases, neoplastic plasma cells were ICAM-1 positive and LFA-1 negative in two cases except for this case (case 1 in Table I), which was consistent with the study of Tsutani et al. [l]. So, we think LFA- I and ICAM-I double positive neoplastic plasma cells in this case is instructive. Expression of LFA-1 has been reported to correlate with cell proliferation and homing to extramedullaly sites [2]. Our case relapsed with a femoral plasmacytoma in December 1992. We speculate that LFA-I positive circulating neoplastic plasma cells might play an important role in localized tumorous relapse. With regard to the second point, we, unfortu- nately, did not examine adhesion molecules on the neoplastic cells during the interferon therapy or at the time of relapse. We, therefore, are not able to comment about the change of adhesion molecules on neoplastic plasma cells in this case.

We expect that advances in the study of the adhesion molecule will reveal many important biological features of neoplastic plasma cells in the future.

NOBORU YAMAGATA CHIHIRO SHIMAZAKI TETSUYA TATSUMI

HIDEO GOTO MASAO NAKAGAWA

Second Department of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan