304 Correspondence

Table 1. Serum Hp and p2-M levels (MeankSD) in the control subjects and patients with ITP

Group No. of cases Hp (g/l) P2-M (mg/l)

Control 110 0.26k0.08 1.79k0.64 Patients 86 0.61 k0.14 3.64+0.72

age, sex, disease duration, haemoglobin, peri- pheral leucocyte and platelet counts, bone marrow megakaryocyte count, PAIgG content, serum H p and P2-M concentrations.

Our study shows that chronic ITP patients have high serum H p and p2-M levels. Although patients who are not haemolysing generally have normal H p levels, we acknow- ledge that our patients did indeed have a high H p concentration. In view of their normal renal and hepatic status, the potential confounding effects of renal and hepatic impairment on H p and P2-M levels can be excluded (Wejman et al. 1984). We suggest that the increase of serum H p and P2-M con- centrations were possibly the result of the same immune response which caused the ITP itself. Antigen-antibody complexes stimulated the mononuclear phagocyte system producing interleukin (ILI). The latter might then have induced the activating T-helper cells to express the receptor of interleukin 2 (IL2) and to produce IL2, strengthening the immune response. Meanwhile, IL1 triggered a reaction of synthesis and secretion of H p in the liver (Waites, Bell & Bell 1983). High H p concentra- tions markedly inhibit B lymphocyte differen- tiation, and modify the immune response. Hence, elevation of H p level in ITP is a self- defence mechanism of the human body (Baseler & Burrell 1983). On the other hand, immune responses also promote an increased proliferation and turnover of the immune system cells, which may enhance the P2-M reaction. While lymphoid cells are the main source of increased serum P2-M in this disorder there is evidence that high B2-M con- centrations can be associated with conditions that cause a pronounced stimulation of the macrophage and reticuloendothelial system (Cooper et al. 1984).

In addition, 24 patients were followed before and after treatment. Because underlying therapy such as steroids may alter the results, the group were not on therapy at the time that

they were first studied. Our results showed that when the patients’ clinical symptoms had improved, their platelet counts increased by a mean value of 66.8 x 109/l; H p and B2-M concentrations decreased by an average of 0.33 g/l and 1.81 mg/l compared to pre-treat- ment values (n = 24, t = 4.72,3.87 respectively, P < 0.05). Furthermore, for the patients with a stable, compensated thrombocytopenia, their H p and P2-M concentrations increased mini- mally. While some of them relapsed, their H p and P2-M levels rose again. Thus it is suggested that the sequential determination of H p and 82-M might be useful in monitoring disease activity and therapeutic response as well as in evaluating the prognostic signifi- cance of chronic ITP.

References

BASELER M.W. & BURRELL R. (1983). Purification of Hp and its effects on lymphocyte and alveolar macrophage response. Injammation 7 , 387-400.

COOPER E.H., FORBES M.A., BOWEN M., GABUTTI V. & PICA A. (1984). Plasma P2-microglobulin and fibronectin levels in beta thalassaemia. Acia Hemarol. 302, 257-262.

WAITES G., BELL A.M. & BELL S.C. (1983) Acute phase proteins in syngeneic and allogeneic mouse pregnancy. Clin. Exp. Immunol. 53,

WEJMAN J.C., HOVSEPIAN D., WALL J.S., HAINFELD J.F. & GREER J. (1984) Structure of Hp and Hp-Hb complex. 1. Mol. Biol. 174, 319-341.

Qingxue Cao, Weiquan Weng,

Chunyuan Zhang, Liting Yang

225-232.

Qingdao Medical College Hospital Department of Internal Medicine Qingdao, P.R. China

Correspondence to: Qingxue Cao, Klinik 1 fur Innere Medizin, der Universtat zu Koln, KMT-Labor, Haus 1 la , Joseph-Stelzmann- StraDe 9, 5000 Koln 41, Germany.

Skin puncture blood counts

Sir: Haematologic values have been contrasted between venous blood (VB) and that obtained by skin puncture (SPB) (Feusner et al. 1979; Mayer et al. 1980; Lippi et al. 1985; Bellamy & Hinchcliffe 1988), but little information is available on the comparison of the differential distribution of leucocytes from these two

Correspondence 305

Table 1. White cell blood count ( x 1091)

Venous blood Skin puncture blood

Mean (SD; range) Mean (SD; range) P-value

Entire group 7.68 (10.64; 0.65-82.76) 7.26 (7.49; 0.65-55.30) 0.800 Low WBC count 2.05 (0.96; 0.65- 3.60) 2.02 (0.88; 0.68- 3.17) 0.820 High WBC count 28.68 (24.32; 14.94-82.76) 23.84 (14.37; 14.08-55.30) 0.350

Table 2. White cell blood count differential (per cent)

Venous blood Skin puncture blood

Mean (SD; range) Mean (SD; range) P-value

Neutrophils 53.3 (15.6; 5.9-85.2) 53.5 (17.4; 3.1-87.8) 0.947

Monocytes 6.3 (2.6; 1.1-14.0) 6.7 (2.7; 0-15.8) 0.225 Lymphocytes 32.5 (16.9; 4.1-87.9) 32.0 (16.9; 0-90.4) 0.837

Eosinophils 2.7 (3.6; 0-20.2) 2.7 (3.5; 0-20.9) 0.971 Basophils 1.3 (1.6; (r10.9) 1.3 (1.3; 0- 8.7) 0.839 LUCs* 4.8 (5.6;0.6-29.1) 4.7 (5.4iO.3-28.1) 0.905

*LUG: large unstained cells.

sources using modern automated counters. Accordingly, paired samples were obtained from 50 adults with a variety of diseases and ten normal healthy volunteers, with the respec- tive volumes being 5 ml collected by vene- puncture into EDTA and 0.5 ml by the percutaneous route (Stuart et al. 1974).

Within one h of collection, analyses were carried out on the Technicon H1 analyser (Miles Diagnostics, Tarrytown, NY, USA), which has been documented to render precise and accurate neutrophil and platelet counts (Swaim, 1991; Buttarello et al. 1992). No difference in mean total white blood cell count could be demonstrated, irrespective of whether leucopenia or leucocytosis was present (Table 1). Similarly, the differential spread was concordant between the samples obtained by the two techniques (Table 2).

It is concluded that whereas there are some significant differences reported in the haemo- globin, red cell count and haematocrit, the differential is reliable when small volumes of capillary blood are collected and this is of practical importance in children or adults when VB is difficult to obtain for any reason.

References BELLAMY G.J. & HINCHCLIFFE E.R. (1988) Venous

and skin puncture blood counts compared. Clin. lab. Haemat. 10, 329-334

BUTTARELLO, M., GADOTTI M., LORENZ C., TOFFALORI E., CESCHINI N., VALENTINI A. & TIZZOTTI P. (1992) Evaluation of four auto- mated hematology analyzers. Am. J. Clin. Pathol. 97, 345-352

FEUSNER J.H., BEHRENS J.A., DETTER J.C. & CULLEN T.C. (1979) Platelet counts in capillary blood. Am. J. Clin. Pathol. 72, 410-414

LIPPI U., CAPPELLETTI P., SCHINELLA M. & SIGNORI D. (1985) Mean platelet volumes: facts or arti- facts? Am. J. Clin. Pathol. 84, 1 11-1 13

MAYER K., CHIN B., MAGNES J., THALER H.T., LOTSPEICH C. & BAISLEY A. (1980) Automated platelet counts. A comparative evaluation of latest instrumentation. Am. J. Clin. Pathol. 74,

STUART J., BARRETT B.A. & PRANGNELL D.R. (1974) Capillary blood collection in haematology. J. Clin. Pathol. 27, 869-874

SWAIM W.R. (1991) Laboratory and clinical evalua- tion of white blood cell differential counts. Am. J. Clin. Pathol. 95, 381-388

135-1 50

R. Dreyer G.S. Pillay

P. Jacobs

Department oj’ Haematology University of Cape Town Leukaeniia Centre and Groote Schuur Hospital Observatory Cape South Africa