Early hematopoietic zinc finger protein prevents tumor cell recognition by natural killer cells

Early hematopoietic zinc finger/zinc finger protein 521 (EHZF/ZNF521) is a novel zinc finger protein expressed in hematopoietic stem and progenitor cells and is down-regulated during their differentiation. Its transcript is also abundant in some hematopoietic malignancies. Analysis of the changes in the antigenic profile of cells transfected with EHZF cDNA revealed up-regulation of HLA class I cell surface expression. This phenotypic change was associated with an increased level of HLA class I H chain, in absence of detectable changes in the expression of other Ag-processing machinery components. Enhanced resistance of target cells to NK cell-mediated cytotoxicity was induced by enforced expression of EHZF in the cervical carcinoma cell line HeLa and in the B lymphoblastoid cell line IM9. Preincubation of transfected cells with HLA class I Ag-specific mAb restored target cell susceptibility to NK cell-mediated lysis, indicating a specific role for HLA class I Ag up-regulation in the NK resistance induced by EHZF. A potential clinical significance of these findings is further suggested by the inverse correlation between EHZF and MHC class I expression levels, and autologous NK susceptibility of freshly explanted multiple myeloma cells.

Propranolol causes a paradoxical enhancement of cardiomyocyte foetal gene response to hypertrophic stimuli

BACKGROUND AND PURPOSE

Pathological cardiac hypertrophy is associated with the expression of a gene profile reminiscent of foetal development. The non selective beta-adrenoceptor antagonist propranolol is able to blunt cardiomyocyte hypertrophic response in pressure-overloaded hearts. It remains to be determined whether propranolol also attenuates the expression of hypertrophy-associated foetal genes.

EXPERIMENTAL APPROACH

To address this question, the foetal gene programme, of which atrial natriuretic peptide (ANP), the beta-isoform of myosin heavy chain (beta-MHC), and the alpha-skeletal muscle isoform of actin (skACT) are classical members, was induced by thoracic aortic coarctation (TAC) in C57BL/6 mice, or by phenylephrine, a selective alpha(1)-adrenoceptor agonist, in cultured rat neonatal cardiomyocytes.

KEY RESULTS

In TAC mice, the left ventricular weight-to-body weight (LVW/BW) ratio increased by 35% after 2 weeks. Levels of ANP, beta-MHC and skACT mRNA in the left ventricles increased 2.2-fold, 2.0-fold and 12.1-fold, respectively, whereas alpha-MHC and SERCA mRNA levels decreased by approximately 50%. Although propranolol blunted cardiomyocyte growth, with approximately an 11% increase in the LVW/BW ratio, it enhanced the expression of ANP, beta-MHC and skACT genes (10.5-fold, 27.7-fold and 22.7-fold, respectively). Propranolol also enhanced phenylephrine-stimulated ANP and beta-MHC gene expression in cultured cardiomyocytes. Similar results were obtained with metoprolol, a selective beta(1)-adrenoceptor antagonist, but not with ICI 118551, a beta(2)-adrenoceptor antagonist.

CONCLUSIONS AND IMPLICATIONS

Propranolol enhances expression of the hypertrophy-associated foetal genes mainly via the beta(1)-adrenoceptor blockade. Our results also suggest that, in pressure-overloaded hearts, cardiomyocyte growth and foetal gene expression occur as independent processes.

[Amyloid cardiomyopathy: a link between cardiology and hematology. A case report of positive response to standard therapy]

Cardiac involvement in primary systemic amyloidosis, due to amassing of fragments of light chains, is detected in the majority of cases. We report the case of a 56-year-old woman who came to our observation because of symptoms of congestive heart failure. Diagnosis of restrictive cardiomyopathy was made by echocardiographic examination, which showed right ventricular hypertrophy, disarray of interventricular septum and restrictive flow pattern at the mitral valve. Primary systemic amyloidosis was diagnosed by abdominal fat pad biopsy. Laboratory findings confirmed biopsy results, leading to the definite diagnosis of restrictive cardiomyopathy due to IgA kappa monoclonal gammopathy in primary systemic amyloidosis.

Prospective, randomized study of single compared with double autologous stem-cell transplantation for multiple myeloma: Bologna 96 clinical study

PURPOSE

We performed a prospective, randomized study of single (arm A) versus double (arm B) autologous stem-cell transplantation (ASCT) for younger patients with newly diagnosed multiple myeloma (MM).

PATIENTS AND METHODS

A total of 321 patients were enrolled onto the study and were randomly assigned to receive either a single course of high-dose melphalan at 200 mg/m2 (arm A) or melphalan at 200 mg/m2 followed, after 3 to 6 months, by melphalan at 120 mg/m2 and busulfan at 12 mg/kilogram (arm B).

RESULTS

As compared with assignment to the single-transplantation group (n = 163 patients), random assignment to receive double ASCT (n = 158 patients) significantly increased the probability to attain at least a near complete response (nCR; 33% v 47%, respectively; P = .008), prolonged relapse-free survival (RFS) duration of 18 months (median, 24 v 42 months, respectively; P < .001), and significantly extended event-free survival (EFS; median, 23 v 35 months, respectively; P = .001). Administration of a second transplantation and of novel agents for treating sequential relapses in up to 50% of patients randomly assigned to receive a single ASCT likely contributed to prolong the survival duration of the whole group, whose 7-year rate (46%) was similar to that of the double-transplantation group (43%; P = .90). Transplantation-related mortality was 3% in arm A and 4% in arm B (P = .70).

CONCLUSION

In comparison with a single ASCT as up-front therapy for newly diagnosed MM, double ASCT effected superior CR or nCR rate, RFS, and EFS, but failed to significantly prolong overall survival. Benefits offered by double ASCT were particularly evident among patients who failed at least nCR after one autotransplantation.

Sestamibi and FDG-PET scans to support diagnosis of jaw osteonecrosis

Osteonecrosis of the maxillary or mandibular bone is an infrequent but often severe event occurring in patients who undergo prolonged treatment with bisphosphonates. Histology is in some cases mandatory to differentiate it from neoplastic osteolysis, but a biopsy can further contribute to bone damage. Functional imaging obtained by a tracer that shows oncotropic properties, such as Tc99m-sestamibi, in comparison to a non-tumor-specific substance such as FDG-PET, can support the differential diagnosis, thus avoiding invasive procedures. Four patients affected by multiple myeloma and jaw osteonecrosis were prospectively evaluated by sestamibi and FDG-PET scans. Local diagnosis was performed by clinical, radiological and, in some cases, histological evaluations. Each patient was studied by Tc99m-sestamibi, performed by planar anterior and posterior whole-body scans and SPECT of the head and neck, and by PET/CT. Two nuclear medicine physicians, unaware of the final diagnosis, reviewed the images. No sestamibi uptake was evident in the four patients with jaw osteonecrosis, while FDG-PET/CT showed focal uptake in all of them. Our study suggests that the combined use of sestamibi scintigraphy and FDG-PET/CT could support the clinical diagnosis of oral osteonecrosis avoiding the risks of a surgical biopsy. Studies on higher number of patients are necessary to validate these preliminary observations.

Oral melphalan and prednisone chemotherapy plus thalidomide compared with melphalan and prednisone alone in elderly patients with multiple myeloma: randomised controlled trial

BACKGROUND

Since 1960, oral melphalan and prednisone (MP) has been regarded as the standard of care in elderly multiple myeloma patients. This multicentre randomised trial compared oral MP plus thalidomide (MPT) with MP alone in patients aged 60-85 years.

METHODS

Patients with newly diagnosed multiple myeloma were randomly assigned to receive oral MP for six 4-week cycles plus thalidomide (n=129; 100 mg per day continuously until any sign of relapse or progressive disease) or MP alone (n=126). Analysis was intention-to-treat. This study is registered at , number NCT00232934.

RESULTS

Patients treated with thalidomide had higher response rates and longer event-free survival (primary endpoints) than patients who were not. Combined complete or partial response rates were 76.0% for MPT and 47.6% for MP alone (absolute difference 28.3%, 95% CI 16.5-39.1), and the near-complete or complete response rates were 27.9% and 7.2%, respectively. 2-year event-free survival rates were 54% for MPT and 27% for MP (hazard ratio [HR] for MPT 0.51, 95% CI 0.35-0.75, p=0.0006). 3-year survival rates were 80% for MPT and 64% for MP (HR for MPT 0.68, 95% CI 0.38-1.22, p=0.19). Rates of grade 3 or 4 adverse events were 48% in MPT patients and 25% in MP patients (p=0.0002). Introduction of enoxaparin prophylaxis reduced rate of thromboembolism from 20% to 3% (p=0.005).

CONCLUSION

Oral MPT is an effective first-line treatment for elderly patients with multiple myeloma. Anticoagulant prophylaxis reduces frequency of thrombosis. Longer follow-up is needed to assess effect on overall survival.

Bortezomib (Velcade) for progressive myeloma after autologous stem cell transplantation and thalidomide

Twenty-one patients with multiple myeloma, all relapsed after frontline autologous stem cell transplantation and all relapsed again after or resistant to thalidomide (employed as second line treatment) received bortezomib (1.3 mg/m(2) body surface twice weekly for 2 weeks followed by an interval of 10-12 days) without adjunct of steroids as third line therapy. Three patients died of progressive disease during the first 2 cycles with bortezomib. Eighteen patients received at least 2 cycles and were evaluated for response. According to EBMT criteria, two complete (negative immunofixation) and seven partial (reduction of M-component > 50-75%) remissions were achieved (ITT response rate 42.8%). Duration of response lasted from 2 to 14+ months. Grades 3-4 toxicities (thrombocytopenia, leucopenia, peripheral neuropathy and vasculitis) were observed in seven patients, but no patient interrupted the treatment due to side effects. We conclude that bortezomib alone may induce high quality responses as third line salvage therapy with acceptable toxicity in a significant proportion of homogeneously pre-treated myeloma patients with progressive disease after autologous transplantation and thalidomide.

Washout of [99mTc] sestamibi in predicting response to chemotherapy in patients with multiple myeloma

AIM

Technetium-99m 2-methoxy-isobutyl-isonitrile ([99mTc] MIBI) has been successfully used to study patients with multiple myeloma (MM). This tracer is also a substrate for P-glycoprotein (Pgp). Since Pgp overexpression is one of the primary mechanisms of multidrug resistance in MM, the aim of this study was to test whether [99mTc] MIBI could be an index of Pgp overexpression and function in MM and therefore predicts response to chemotherapy.

METHODS

Forty patients with MM (12 in stage I, 15 in stage II, and 13 in stage III) showing diffuse bone marrow [99mTc] MIBI uptake were included in the study. All patients underwent whole body scintigraphy at 10 and 60 minutes after i.v. injection of 555 MBq of [99mTc] MIBI. [99mTc] MIBI washout was measured, after decay correction, as: (10 minute counts/pixel minus 60 minute counts/pixel) divided by 10 minute counts/pixel, computed on a region of interest drawn on the thoracic spine (posterior projection), taking care of avoiding heart and splanchnic organs. Disease restaging was performed at a mean time of 32+/-20 months, and patients were considered to be in remission (complete or partial) or to show disease progression on the basis of a complete clinical and hematological evaluation.

RESULTS

Patients showing disease progression at restaging (n=26) had higher washout (19.3+/-9.8% vs 12.8+/-6.9%, p<0.05) than patients in remission (n=14). Disease free survival was significantly better in patients with lower washout of [99mTc] MIBI. No differences in therapeutic regimen and stage of disease at admission were found between the 2 groups. When patients treated with melphalan were excluded from the analysis, 87.5% of patients in remission had low washout.

CONCLUSIONS

The present study suggests a potential role of [99mTc] MIBI washout in predicting response to chemotherapy in patients with MM.

Tc99m-sestaMIBI uptake in nonsecretory multiple myeloma

Staging and monitoring of multiple myeloma (MM) is mainly based on monoclonal component quantification; the absence of such a parameter renders difficult follow up of patients with nonsecretory MM (nsMM). In this study our aims were to determine the specificity and sensitivity of Tc99m-sestaMIBI scintigraphy at diagnosis and during follow up of nsMM patients. Nine nsMM patients were prospectively studied at diagnosis and during treatment for a mean time of 33 months (range: 12-65+). Tc99m-sestaMIBI (MIBI) scintigraphy was compared to conventional imaging (CI: X ray with CAT or NMR details) at diagnosis and during follow up. At diagnosis, CI and MIBI were concordant in three patients; CI showed more focal lesions than MIBI in four patients, while MIBI revealed more focal lesions than CI in two patients. During the follow up, MIBI uptake was normal in the four patients who achieved remission. Five patients did not achieve remission: CI and MIBI were concordant in three, while MIBI was falsely negative in two patients. In conclusion, Tc99m-sestaMIBI scintigraphy has high sensitivity (no false positive cases) and 78% specificity (2/9 false negative cases) in tracing active nsMM lesions; it should be considered complementary to CI for monitoring this rare disease.

Delta-CHr improves the identification of anemic syndromes and the evaluation of hemoglobin synthesis

Reticulocyte hemoglobin content (CHr) is considered an index of iron status, helpful in the differential diagnosis of microcytoses. Its potential can be enhanced by comparing CHr dynamic reference values (CHr-e: expected CHr), which are proportional to the MCVr variations occurring in micro- or macrocytosis, with measured CHr values. We demonstrate that the difference between measured CHr and CHr-e (DeltaCHr) is helpful to differentiate the anemic syndromes and, in particular, beta-thalassemia vs. presumable sideropenia. DeltaCHr can also indicate when to interrupt iron supplementation. DeltaCHr allows an insight into the erythropoiesis of thalassemic and sideropenic subjects, pointing out the reduced hemoglobin production and ineffective erythroid activity in these conditions.

HLA class I, NKG2D, and natural cytotoxicity receptors regulate multiple myeloma cell recognition by natural killer cells

The role of natural killer (NK) cells in multiple myeloma is not fully understood. Here, NK susceptibility of myeloma cells derived from distinct disease stages was evaluated in relation to major histocompatibility complex (MHC) class I, MHC class I chain-related protein A (MICA), MHC class I chain-related protein B (MICB), and UL16 binding protein (ULBP) expression. MHC class I molecules were hardly detectable on bone marrow cells of early-stage myeloma, while late-stage pleural effusion-derived cell lines showed a strong MHC class I expression. Conversely, a high MICA level was found on bone marrow myeloma cells, while it was low or not measurable on pleural effusion myeloma cells. The reciprocal surface expression of these molecules on bone marrow- and pleural effusion-derived cell was confirmed at mRNA levels. While bone marrow-derived myeloma cells were readily recognized by NK cells, pleural effusion-derived lines were resistant. NK protection of pleural effusion cells was MHC class I dependent. Receptor blocking experiments demonstrated that natural cytotoxicity receptor (NCR) and NK receptor member D of the lectin-like receptor family (NKG2D) were the key NK activating receptors for bone marrow-derived myeloma cell recognition. In ex vivo experiments patient's autologous fresh NK cells recognized bone marrow-derived myeloma cells. Our data support the hypothesis that NK cell cytotoxicity could sculpture myeloma and represents an important immune effector mechanism in controlling its intramedullary stages.

Functional Imaging of Multidrug Resistant Phenotype by 99mTc-MIBI Scan in Patients with Multiple Myeloma

Overexpression of P-glycoprotein (Pgp) is one of the primary mechanisms of multidrug resistance (MDR) in several diseases, including multiple myeloma. The aim of this study was to investigate whether the washout of 99mTc-MIBI, a transport substrate of Pgp, is enhanced in the bone marrow of patients with multiple myeloma overexpressing Pgp. Seventeen (17) patients were i.v. injected with 555 MBq of 99mTc-MIBI, and whole-body scans were performed at 10 and 60 minutes. A region of interest (ROI) was drawn over the thoracic spine of each scan, and the washout of 99mTc-MIBI was calculated, after decay correction, as: (10-minute counts/pixel minus 60-minute counts/pixel) divided by 10-minute counts/pixel. Pgp expression was determined in 17 bone marrow samples obtained from the same patients immediately before the 99mTc-MIBI scan. Following centrifugation over the Ficoll-Hypaque gradient, cytospins were obtained and immunostained with C219 monoclonal antibody. The immunostaining of Pgp was graded as 1, 2, or 3 when a faint, moderate, or intense reaction, respectively, was observed in infiltrating plasma cells. Washout of 99mTc-MIBI ranged between 5% and 26%. A statistically significant direct correlation was found between the washout of the tracer and Pgp expression (Spearman rank correlation coefficient r = 0.74, p < 0.001). A partial overlap of washout values was observed in different classes of Pgp expression, thus preventing the discrimination of individual patients. Washout of 99mTc-MIBI, expressed as the percentage of radioactivity cleared from the bone marrow over a 1-hour period, may be used as a noninvasive tool for in vivo whole-body imaging of Pgp expression and function in multiple myeloma patients.

A case of hypereosinophilic cardiomyopathy: additional value of the myocardial contrast agent SonoVue for the differential diagnosis of a cardiac mass

We describe the case of a 37-year-old male referred because of hypereosinophilia associated with dyspnea. Transthoracic harmonic echocardiography showed an extensive myocardial infiltration and highlighted an intraventricular "in plus" image, whose characteristics were compatible with a diagnosis of intracardiac thrombus. The use of the myocardial contrast agent SonoVue (1 ml in bolus i.v. and 4 ml at an infusion velocity of 2 ml/min) allowed us to immediately identify, during left ventricular chamber opacification, the exact endocardial border of the left ventricular cavity and, later (when the residual SonoVue was evident only at the level of the myocardial walls), the true characteristics of the "in plus" image. This approach revealed the infiltration of the myocardial tissue and of both papillary muscles and chordae tendinae. The use of the myocardial contrast agent SonoVue may be, therefore, useful to distinguish the origin of "in plus" images often evident at echocardiography in the hypereosinophilic syndrome.

Effects of cyclosporine on hematopoietic and immune functions in patients with hypoplastic myelodysplasia: in vitro and in vivo studies

BACKGROUND

Immunosuppression may benefit some patients with hypoplastic myelodysplasia (HMDS) and refractory anemia (RA), but its mechanism of action is still obscure.

METHODS

Using flow cytometry, we studied Fas-receptor (Fas-R), Fas-ligand (Fas-L), and interferon-gamma (IFN-gamma) expression in CD34(+) cells and lymphocytes obtained from 11 HMDS and 20 RA patients. In colony assays and long-term cultures, the effects of Fas triggering, IFN-gamma blockade, or cyclosporine(CsA) on the growth of hematopoietic progenitors (colony-forming cells [CFC]) were determined. The effects of CsA at daily doses of 1-3 mg/kg for at least 3 months in HMDS patients were also studied.

RESULTS

In basal conditions, committed and immature progenitor cells were found decreased in myelodysplastic (MDS) patients. No significant differences between HMDS and RA patients were detected. IFN-gamma-expressing CD4(+) cells were significantly increased in HMDS patients, whereas intracytoplasmic Fas-L expression was only borderline elevated in CD3(+) MDS cells. Increased numbers of CD34(+) cells expressing Fas-R were found in HMDS and RA patients. CFC and secondary CFC showed higher susceptibility to Fas-L-mediated inhibition and the blockade of IFN-gamma improved marrow primary, but not secondary, CFC growth. CsA added in vitro to patient's lymphocytes significantly decreased the number of IFN-gamma-expressing CD4(+) cells, but not Fas-L production. These effects were associated with increased colony formation. Similar to IFN-gammablockade, production of secondary CFC was not enhanced by CsA. Administration of CsA to patients resulted in prolonged partial hematologic improvement in 8 of 11 HMDS patients.

CONCLUSIONS

Increased frequency of IFN-gamma producing CD4(+) cells supports the involvement of lymphocyte-mediated suppression of hematopoiesis in the development of cytopenia in MDS patients. The ability of CsA to decrease in vitro IFN-gamma production may improve hematopoietic function, explaining the beneficial effect of this agent in HMDS patients.

Functional imaging of Langerhans cell histiocytosis by (111)In-DTPA-D-Phe(1)-octreotide scintigraphy

BACKGROUND

Langerhans cell histiocytosis is a rare group of diseases of unknown pathogenesis, variable clinical presentation, and behavior. It encompasses highly aggressive, often fatal, and indolent diseases, with a variety of intermediate forms between the two extremes. Localization and monitoring of Langerhans cell histiocytosis deposits are based on the combined use of different imaging modalities, which include magnetic resonance, computed tomography, and nuclear medicine procedures. Somatostatin receptor scintigraphy recently has been used to image immune-mediated diseases with excellent results.

METHODS

In this study, the authors have evaluated the potential role of somatostatin receptor scintigraphy by using (111)In-DTPA-D-Phe(1)-octreotide in a series of patients with Langerhans cell histiocytosis. Eight consecutive patients (2 males, 6 females; mean age, 43 years; age range, 29-60 years) with histologically proven Langerhans cell histiocytosis, in various phases of their disease, were imaged 24 hours after intravenous injection of 111-222 MBq of (111)In-DTPA-D-Phe(1)-octreotide, by using total body and spot view images. The objective of the study was to preliminarily evaluate this technique in the evaluation of Langerhans cell histiocytosis.

RESULTS

Most Langerhans cell histiocytosis deposits were clearly documented by somatostatin receptor scintigraphy, independently from the anatomic location (i.e., skeleton, mucosae, soft tissue, etc.). The correlation between conventional imaging modalities and somatostatin receptor scintigraphy results was fairly good, though this was not considered a primary objective of the study.

CONCLUSIONS

Among the various imaging modalities for Langerhans cell histiocytosis, somatostatin receptor scintigraphy is unique, because it accurately depicts the active sites of disease and thus can help in monitoring the response to treatment, together with conventional imaging modalities. Further studies are necessary to confirm the diagnostic value of this technique and clarify the biologic significance of the expression of somatostatin receptors in Langerhans cell histiocytosis.

Predictive value of technetium-99m sestamibi in patients with multiple myeloma and potential role in the follow-up

Technetium-99m 2-methoxyisobutylisonitrile (99mTc-MIBI or setamibi) has recently been proposed for use in the evaluation of multiple myeloma (MM). The aims of this study were to investigate its potential predictive value in patients with MM and its possible role in the follow-up. Thirty patients with MM who had undergone two 99mTc-MIBI scintigraphic studies at least 2 months apart constituted the study group; 22 of them received chemotherapy in the interval between the two scans. The scans were classified as showing pattern N when only physiological uptake was present, pattern D when diffuse bone marrow uptake was observed, pattern F when areas of focal uptake of the tracer were evident, and pattern F + D when both D and F patterns were observed. Comparative 99mTc-MIBI scintigraphy was considered indicative of disease progression when there was a worsening of the pattern (i.e. from N to D, or from N or D to F or to F + D) or an increase in the pattern D semiquantitative score. It was considered indicative of disease improvement when the opposite trend was observed; otherwise, it was considered to document a stable condition. A significant association was observed between the baseline scintigraphic pattern and clinical status at follow-up in the group of patients evaluated after chemotherapy (chi 2 = 16.7, P < 0.05). A negative baseline 99mTc-MIBI scintigram showed a high predictive accuracy (100%) for remission, while the presence of pattern F or F + D was often associated with a less favourable outcome. A multivariate analysis showed that 99mTc-MIBI uptake pattern has an added value in relation to known prognostic variables such as C-reactive protein. 99mTc-MIBI scintigraphy patterns at follow-up were significantly associated with the clinical status evaluated after chemotherapy (chi 2 = 32.6, P < 0.0001). Considering pattern N as indicating remission, pattern D stable condition, and pattern F or F + D progressive disease, a high concordance between scintigraphic findings and clinical status was found in the 22 patients undergoing chemotherapy (91%). Variation in 99mTc-MIBI findings comparing baseline and follow-up evaluations was significantly associated with clinical status both in patients undergoing chemotherapy (chi 2 = 26.5, P < 0.0005) and in those not undergoing chemotherapy (chi 2 = 8.0, P < 0.005). In conclusion, the results of this study suggest a prognostic value of 99mTc-MIBI scintigraphy in patients with MM and a potential role during the follow-up.

Bone marrow uptake of 99mTc-MIBI in patients with multiple myeloma

In a previous study, we showed the ability of technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) scan to identify active disease in patients with multiple myeloma (Eur J Nucl Med 1998; 25: 714-720). In particular, a semiquantitative score of the extension and intensity of bone marrow uptake was derived and correlated with both the clinical status of the disease and plasma cell bone marrow infiltration. In order to estimate quantitatively 99mTc-MIBI bone marrow uptake and to verify the intracellular localization of the tracer, bone marrow samples obtained from 24 multiple myeloma patients, three patients with monoclonal gammopathy of undetermined significance (MGUS) and two healthy donors were studied for in vitro uptake. After centrifugation over Ficoll-Hypaque gradient, cell suspensions were incubated with 99mTc-MIBI and the uptake was expressed as the percentage of radioactivity specifically retained within the cells. The cellular localization of the tracer was assessed by micro-autoradiography. Twenty-two out of 27 patients underwent 99mTc-MIBI scan within a week of bone marrow sampling. Whole-body images were obtained 10 min after intravenous injection of 555 MBq of the tracer; the extension and intensity of 99mTc-MIBI uptake were graded using the semiquantitative score. A statistically significant correlation was found between in vitro uptake of 99mTc-MIBI and both plasma cell infiltration (Pearson's coefficient of correlation r=0.69, P<0.0001) and in vivo score (Spearman rank correlation coefficient r=0.60, P<0.01). No specific tracer uptake was found in bone marrow samples obtained from the two healthy donors. Micro-autoradiography showed localization of 99mTc-MIBI inside the plasma cells infiltrating the bone marrow. Therefore, our findings show that the degree of tracer uptake both in vitro and in vivo is related to the percentage of infiltrating plasma cells which accumulate the tracer in their inner compartments.

Prolonged response to cyclosporin-A in hypoplastic refractory anemia and correlation with in vitro studies

BACKGROUND AND OBJECTIVE

Lymphocyte abnormalities in myelodysplastic syndromes (MDS) have been widely described, but the role of the immune system in the pathogenesis of these clonal disorders remains controversial. An active role of lymphocytes in suppressing normal hematopoiesis may be implicated in MDS with hypoplastic marrow. We have studied in vitro and in vivo activity of cyclosporin-A (CSA) on hematopoiesis in patients affected by hypoplastic MDS without blast excess.

DESIGN AND METHODS

Nine consecutive patients with hypoplastic refractory anemia (RA), followed up in our out-patient unit, were treated with CSA at daily doses of 1-3 mg/kg for at least three months. Low dose steroids or danazol were transiently added in 7/9 patients. Differences between pre- and post-treatment parameters were studied by the Student's t-test. In vitro effect of CSA on circulating hematopoietic progenitors was studied by the methylcellulose colony assay.

RESULTS

Before treatment, fewer circulating hematopoietic progenitors were found in all patients as compared to normal subjects. The number of CD34+ cells was about halved, while circulating erythroid and myeloid colony-forming cells (CFC) were reduced to one-fifth. After a mean period of 22 months of CSA treatment (median: 14.5 months), hemoglobin was significantly and persistently increased in two patients, platelets in one, platelets and hemoglobin in two. Two patients showed transient responses, one patient did not tolerate the treatment and one patient is close to a significant response. At in vitro CSA concentrations similar to those achieved in vivo after oral administration the drug significantly increased cell colony growth in hypoplastic RA. This test correctly predicted a positive clinical response to CSA in 3/5 cases and treatment failure in 4/4 cases.

INTERPRETATION AND CONCLUSIONS

About one half of hypoplastic RA patients benefited from CSA treatment. A larger study could verify whether in vitro culture of hematopoietic progenitors in the presence of CSA can predict the clinical response and whether this treatment could prolong patients' survival.