1092

KLINEFELTER SYNDROME: PREDISPOSITION TOACUTE NON-LYMPHOCYTIC LEUKÆMIA?

SIR,-Our letter which appeared in your April 5 issue

(p. 774) contained an unfortunate misprint: the proportion ofmales with a 47,XXY karyotype at birth was shown as about1 per 100 instead of 1 per 1000 as in the text submitted. Manywould doubtless have recognised the error and accepted thecase but there could be others who did not and who wouldhave instinctively assessed the likelihood of drawing 4 in asample of 60 where the population frequency is 0.01 as notbeing particularly low for an anecdotal report. They would beright. The binomial probability of such a sample (4 in 60) is0.022 when the population frequency is 0.01, but becomes0.33 x 10-4 when the frequency is 0.001.

Since we submitted our letter we have found another patientwith Klinefelter syndrome and acute (myelomonocytic) leukae-mia. All 20 cells studied from bone marrow as well as stimu-lated peripheral blood lymphocytes had a 47,XXY karyotype.This fifth patient was one of the 6 newly diagnosed patientswith acute non-lymphocytic leukaemia we have studied chro-mosomally since the beginning of the year.

Department of Human Genetics, J P M GUniversity of Leiden, J. P. M. GERAEDTS

2333 AL Leiden, Netherlands C. E. FORDE. BRIET

Department of Heematology, C. A. HARTGRINK-GROENEVELDUniversity of Leiden G. J. DEN OTTOLANDER

Department of Human Genetics,University of Leiden,2333 AL Leiden, Netherlands

J. P. M. GERAEDTSC. E. FORDE. BRIËT

Department of Hæmatology,University of Leiden

C. A. HARTGRINK-GROENEVELDG. J. DEN OTTOLANDER

ARE MOST "NULL" CELLS B CELLS?

SIR,-Haegert and Coombsl have argued that most conven-tionally characterised "null" cells can be placed on the B lym-phocyte differentiation pathway because they express en-

dogenously synthesised surface membrane immunoglobulin(SmIg) in quantities not detectable by direct immunofluores-cence (DIF) but demonstrable by sensitive rosette tests such asthe direct antiglobulin or mixed antiglobulin rosetting reac-tions. Since patients with X-linked hypogammaglobulinsmlia(XLH) lack DIF-positive B lymphocytes but may have precur-sors of B cell lineage,2 Haegert and Coombs suggested thattheir hypothesis could be tested by examining circulating lym-phocytes from these patients for SmIg expression by rosettetest. We had already tested XLH patients as part of a widerstudy, using a rosette test for SmIg3 that is more sensitive than

. conventional DIF (unpublished) and capable of detecting asfew as 1000 Ig molecules/cell.4 Our results demonstrate thatthese immunodeficient patients lack SmIg-rosette-positive lym-phocytes and, in common with normal subjects, have a vari-able number of circulating E-rosette negative, SmIg negative("null") cells. /’

Six boys from three families with this condition were studied; allhave immunodeficient male but normal female relatives, presented in’childhood with recurrent infections, have absent or very low numbersof DIF-positive B lymphocytes, and are in good general health on re-placement intramuscular immunoglobulin. For comparison, threemales with common variable immunodeficiency (CVID) were alsostudied; they lack any family history of antibody deficiency and havevariable numbers of DIF-positive B cells. Lymphocytes were testedwithout knowledge of the diagnosis.

Mononuclear cells (MNC) were prepared from heparinised venousblood by ’Ficoll-Triosil’ density-gradient centrifugation and tested,

1. Haegert D, Coombs RRA. Do human B and null lymphocytes form a singleimmunoglobulin bearing population? Lancet 1979; ii: 1051-52.

2. Dosh HM, Percy ME, Gelfand EW. Functional differentiation of B lympho-cytes in congenital agammaglobulinemia. J Immunol 1977; 119: 1959-64.

3. Ling NR, Bishop S, Jefferis R. Use of antibody-coated red cells for the sensi-tive detection of antigen and in rosette tests for cells bearing surface im-munoglobulins. J Immunol Meth 1977; 15: 279-89.

4. Dhaliwal HS, Ling NR, Bishop S, Chapel H. Expression of immunoglobulinG on blood lymphocytes in chronic lymphocytic leukæmia. Clin Exp Im-munol 1978; 31: 226-37.

SURFACE MARKER PROFILE OF BLOOD LYMPHOCYTES FROM

IMMUNODEFICIENT PATIENTS

*Ages of patients 1-9 were, respectively, 10, 13, 6, 16, 13, and 11 forXLHG, 7,19, and 42 for CVID, and 26+9 for the controls.tSmIg % for classes , 8, Y, and a not shown.+"NuU" cells (%)=100-(%EsRFC+%x+%i.).

after overnight culture at 37°C, for rosette formation with sheep(EsRFC) or mouse (EmRFC) erythrocytes and for SmIg by rosettetesting.4 Since methods used for removing monocytes from the MNCpreparations can cause some selective loss of B cells5 unpurified MNCwere used and the monocytes identified both morphologically and bya yeast ingestion assay.6

All six boys with XLH had absent or very few Smlg-positivelymphocytes while T cell (EsRFC) proportions were normal orincreased; in contrast, the patients with CVID possessed SmIg-positive lymphocytes (table). Patient 7 had a marked increasein B cells, expressing three heavy chains simultaneously; thismarker profile has been previously noted5 and similar types ofB cells, though infrequent, do occur in normal blood and in pa-tients with other lymphoid disorders. Our normal range for Es-rosette forming lymphocytes is comparable with publisheddata, while our normal values for SmIg-positive B cells liebetween the higher percentages reported by Haegert andCoombs’ and the lower proportions detected by DIF assays.’We found null (SmIg-negative, Es rosette-negative) lympho-cytes in normal subjects (mean + SD==9-5±6-2%), in XLH pa-tients (18-0+4.5%), and in those with CVID: these cells werenon-phagocytic but expressed receptors for Fcy (results notshown). The sensitivity of the SmIg rosette test used makes itvery unlikely that B cells expressing low levels of SmIg werenot detected. However, our test differs from that used by Hae-gert and Coombs in that we do not use trypsinised ox indicatorcells, nor require sodium azide or 5% bovine serum albuminfor optimal results.Our evidence therefore suggests that patients with XLH do

possess significant proportions of DIF-negative, Smlg-rosettenegative, Es-rosette negative null lymphocytes, but furtherstudies are required to clarify the nature of these cells.

Department of Immunology,Medical School,University of Birmingham,Birmingham B15 2TJ;

and Regional Department of Immunology,East Birmingham Hospital

H. S. DHALIWALM. R. HAENEYN. R. LING

5. Preud’homme J-L, Seligman M. Surface immunoglobulins on human lym-phoid cells. In: Schwartz RS, ed. Progress in clinical immunology: vol II.New York: Grune and Stratton, 1974: 121-74.

6. Shaala A, Dhaliwal HS, Bishop S, Ling NR. Ingestion of dyed-opsonisedyeasts as a simple way of detecting phagocytes in lymphocyte prepara-tions. Cytophilic binding of immunoglobulins by ingesting cells. J Im-munolMeth 1979; 27: 175-87.

7. Petterson D, Mellstedt H, Holm G. IgG on human blood lymphocytesstudied by immunofluorescence. Scand J Immunol 1978; 8: 535-42.