Correlation of plasma cell percentages by CD138 immunohistochemistry, cyclin D1 status, and CD56 expression with clinical parameters and overall survival in plasma cell myeloma.

CONTEXT: Plasma cell myelomas (PCMs) are traditionally diagnosed by the percentage (%) of plasma cells (PCs) in the bone marrow aspirate differential combined with clinical parameters and radiographic findings. PCs are most reliably quantitated in bone marrow (BM) tissues by CD138 immunohistochemistry (IHC). However, there are no correlations of % CD138+ cells with clinical parameters or overall survival (OS). The presence of cyclin D1 has correlated with worst prognosis, but cyclin D1 has not been correlated with routine cytogenetics. CD56+, although not significantly reported in reactive plasmacytoses, monoclonal gammopathy of undetermined significance (MGUS), nor in lymphoplasmacytic lymphomas (LPLs), has not been evaluated in borderline diagnostic (borderline) cases. OBJECTIVES: It includes: (1) correlating the percentages of PCs by CD138 IHC, cyclin D1 status, and CD56 expression with clinical parameters and OS in PCMs, (2) correlating cyclin D1 status with routine cytogenetics in PCMs, borderline cases, and MGUSs, and (3) analyzing CD56 expression in PCMs, borderline cases, MGUSs, and LPLs. DESIGN: Bone marrow aspirates, BM touch preparations, and BM clot and/or biopsy sections with CD138/kappa/lambda IHC (44-PCMs, 9-MGUSs, 17-borderline cases, 3-LPLs, and 3-reactive plasmacytoses) were reviewed and stained with CD56 and cyclin D1. RESULTS/CONCLUSIONS: Increased CD138+ cells did not correlate significantly with clinical parameters or OS. Cyclin D1+ did not correlate with the presence of a t(11;14) by routine cytogenetics [although detected in all t(11;14)+ cases], clinical parameters, nor OS. CD56 expression was identified in PCMs, MGUSs, and LPL but not in reactive plasmacytoses. CD56+ did not distinguish PCMs, MGUS, and LPLs, and did not correlate with clinical parameters or OS. CD56 and cyclin D1 IHC were better evaluated in BM clot than biopsy sections.     

Extramedullary Relapse of Acute Myelogenous Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation: Better Prognosis Than Systemic Relapse

Allogeneic hematopoietic cell transplantation (HSCT) is considered a curative treatment for acute myelogenous leukemia (AML). Extramedullary relapse after HSCT for AML is a rare event and is less well defined than systemic, hematologic relapse. We retrospectively studied all patients with AML (n = 436) who underwent HSCT at the University of Minnesota between 1996 and 2008 who developed either a bone marrow (BM) or extramedullary (EM) relapse, and examined the incidence and risk factors for BM and EM relapse. Of 128 patients who relapsed post-HSCT, 25 had relapse in EM sites, either isolated (n = 13) or with concurrent BM relapse (n = 12). Relapse sites included bone (n = 1), central nervous system (n = 6), gastrointestinal (n = 4), lymphatic (n = 4), skin (n = 5), genitourinary (n = 1), pulmonary (n = 1), and soft tissue (n = 3). The time to relapse was longer in the EM sites (median, 328 days vs 168 days). Patients with EM relapse were more likely to have had preceding acute graft-versus-host disease (GVHD) (77% vs 49%; P = .03) or chronic GVHD (46% vs 15%; P = .02) compared with those with BM relapse. The 6-month survival postrelapse was significantly better in patients with isolated EM relapse (69%) compared with those with combined EM and BM relapse (8%) or those with BM relapse alone (27%) (P < .01). Compared with local therapy alone, systemic therapy yielded better 6-month survival in patients with EM relapse. This study suggests differing pathogenesis of BM relapse versus EM relapse of AML after allogeneic HSCT. GVHD and its accompanying graft-versus-leukemia effect may better protect BM sites, but patients with EM relapse have better responses to combined therapy and improved survival compared with those with BM relapse.     

Invasive aspergillosis: an important risk factor on the short- and long-term survival of acute myeloid leukemia (AML) patients

Invasive aspergillosis (IA) during induction chemotherapy of acute myeloid leukemia (AML) could worsen the prognosis. Our objective was to study how the development of IA during AML interferes with the therapeutic strategy and to evaluate its impact on the short- and long-term survival. Newly diagnosed AML patients between the years 2004 and 2007 were retrospectively analyzed. The outcome was death of the patient. A Cox proportional hazards model with the diagnosis of IA and post-induction response evaluation as the main exposure was fitted. Overall, 262 patients were analyzed and 58 IA were observed. The 2-year survival of patients having had remission of AML was 54% and, for patients with failure of chemotherapy, it was 5% (p < 0.001). The 2-year survival of patients having had IA was 14%, and without IA, it was 32% (p = 0.01). Multivariate analysis showed that IA was associated with a higher risk of death in case of remission compared to no IA (hazard ratio [HR] = 1.66 [1.05-2.65], p = 0.031) and also in case of failure (HR = 6.43, p < 0.001). IA was associated with an increased risk of death for patients if they were either in remission or in failure after induction chemotherapy.     

Association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia

AIMS: To investigate the association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia. METHODS: Cerebrospinal fluid (CSF) samples from patients with acute myelogenous leukaemia (AML) at diagnosis (n = 2) and acute lymphoblastic leukaemia (ALL) at diagnosis (n = 14) were analysed for parvovirus B19 DNA by means of nested polymerase chain reaction. In addition, samples from patients with benign intracranial hypertension (BIH) (n = 10) and hydrocephalus (n = 13) were tested as controls. RESULTS: Four leukaemia cases were positive-common ALL (n = 2), null cell ALL (n =1), and M7 AML (n = 1)-whereas all controls were negative (Yates corrected chi(2) value, 3.97; p = 0.046; odds ratio, 16.92; confidence interval, 1.03 to 77.18). All four patients were significantly anaemic, but none was encephalitic or had evidence of central nervous system leukaemia. In three of these patients, serum tumour necrosis alpha, interferon gamma, interleukin 6, granulocyte-macrophage colony stimulating factor (range, 34.93-3800.06 pg/ml), and macrophage chemoattractant protein 1 were detectable. All of these four patients carried at least one of the HLA-DRB1 alleles, which have been associated with symptomatic parvovirus B19 infection. CONCLUSION: Erythroid suppression and immune cell proliferation are both associated with B19 infection and may also be important in the pathogenesis of acute leukaemia.     

Subtle CD20 positivity in the bone marrow of a patient who has a mucosa‐associated lymphoid tissue lymphoma should not be regarded as evidence of involvement in the bone marrow

Aims: Bone marrow (BM) biopsies of some mucosa‐associated lymphoid tissue (MALT) lymphoma patients show scattered or small clusters of CD20+ cells without definite lesions (subtle CD20 positivity). The aim of this study was to evaluate the clinical significance of BM involvement and subtle CD20 positivity in 122 patients diagnosed with MALT lymphoma. Methods and results: Patients were divided into three categories: BM involvement [BM(+)], subtle CD20 positivity, and no BM involvement [BM(?)]. Eleven (9%) showed BM involvement, and 17 (14%) showed subtle CD20 positivity. BM(+) patients had significantly worse progression‐free survival (PFS) than BM(?) patients [hazard ratio (HR) 6.25, P = 0.01], but there was no significant difference between subtle CD20 positivity and BM(?) patients. Patients with >30 CD3+ cells among 100 nucleated cells in the areas with increased numbers of CD3+ cells had significantly worse PFS than those with <15 CD3+ cells (HR 5.49, P = 0.02). BM(+) patients with >30 CD3+ cells had worse PFS than those with ≤30 CD3+ cells (P = 0.029), with an extent of BM(+) involvement of >10% positively correlating with >30 CD3+ cells (P = 0.015). Conclusions: Patients with BM(+) MALT lymphoma showed significantly worse PFS than those with subtle CD20 positivity and BM(?) MALT lymphoma, but the PFS of patients with subtle CD20 positivity MALT lymphoma was not significantly different from that of those with BM(?) MALT lymphoma. Increased numbers of BM T cells in MALT lymphoma patients might be suggestive of a worse prognosis.     

CD138/syndecan-1: a useful immunohistochemical marker of normal and neoplastic plasma cells on routine trephine bone marrow biopsies.

Detection of abnormal numbers and/or distribution of bone marrow (BM) plasma cells (PCs) on trephine biopsies can be important in the differential diagnosis of multiple myeloma (MM) and other PC disorders. A variety of immunohistochemical markers can potentially improve the specificity and sensitivity of PC detection on routine histological sections obtained from trephine BM biopsies, but most of them are not completely satisfactory. In this study, we investigated whether the antibody CD138/B-B4, which is an optimal marker for PC detection on BM aspirates by flow cytometry, can be used successfully for the identification of PCs also on formalin-fixed, decalcified biopsies. A series of samples including normal BM [12], MM [65], monoclonal gammopathies of undetermined significance [44], and B-cell lymphoma of various types [94], including B-cell precursor lymphoblastic leukemia [9], lymphoplasmacytoid [17], immunoblastic [14], lymphocytic/CLL [23], hairy cell leukemia [4], large B-cell [8], mantle-cell [3], marginal zone [6] and follicular [10] lymphomas, have been investigated for CD138 expression using a sensitive immunohistochemical technique. Within the BM microenvironment, CD138 was characterized by excellent sensitivity and specificity. Virtually all normal and neoplastic PCs expressed clear-cut membrane CD138 immunostaining, whereas all other cell types did not. All cases of MM, including plasmablastic and leukemic cases, showed strong immunoreactivity. Conversely, all B-cell lymphomas, including all cases characterized by secretive features, lymphoplasmacytoid, and immunoblastic lymphomas, were completely negative. These results demonstrate that CD138 is a highly sensitive and specific marker that is useful for the rapid and precise localization of normal and neoplastic PCs on routine BM sections. In addition, because of its clear-cut cell membrane localization, CD138 can be used successfully in double-marker immunostaining reactions to evaluate precisely nuclear prognostic markers such as Ki67 and p53 in MMs.     

Secondary Acute Myeloid Leukemia and the Role of Allogeneic Stem Cell Transplantation in a Population-Based Setting

Secondary AML (s-AML), including AML with an antecedent hematologic disorder (AHD-AML) and therapy-related AML (t-AML), constitutes a large proportion of patients with AML and is considered to confer a dismal prognosis. The role of allogeneic hematopoietic cell transplantation (HCT) in patients with s-AML and the extent to which HCT is performed in these patients has been little studied to date. We used the population-based Swedish AML Registry comprising 3337 intensively treated adult patients over a 17-year period to study the role of HCT within the group of patients with s-AML as well as compared with patients with de novo AML. HCT was performed in 576 patients (22%) with de novo AML, in 74 patients (17%) with AHD-AML, and in 57 patients (20%) with t-AML. At 5 years after diagnosis, there were no survivors among patients with previous myeloproliferative neoplasms who did not undergo HCT, and corresponding survival for patients with antecedent myelodysplastic syndromes and t-AML was and 2% and 4%, respectively. HCT was compared with chemotherapy consolidation in s-AML using 3 models: (1) a 200-day landmark analysis, in which HCT was favorable compared with conventional consolidation (P = .04, log-rank test); (2) a multivariable Cox regression with HCT as a time-dependent variable, in which the hazard ratio for mortality was 0.73 (95% confidence interval, 0.64 to 0.83) for HCT and favored HCT in all subgroups; and (3) a propensity score matching analysis, in which the 5-year overall survival (OS) and relapse-free survival in patients with s-AML in first complete remission (CR1) was 48% and 43%, respectively, for patients undergoing HCT versus 20% and 21%, respectively, for those receiving chemotherapy consolidation (P = .01 and .02, respectively, log-rank test). Our observational data suggest that HCT improves survival and offers the only realistic curative treatment option in patients with s-AML.     

Allogeneic Hematopoietic Cell Transplantation in Children with Relapsed Acute Lymphoblastic Leukemia Isolated to the Central Nervous System

Allogeneic hematopoietic cell transplantation (HCT) is the standard of care for pediatric patients with early medullary relapse of acute lymphoblastic leukemia (ALL). Most patients with isolated central nervous system (CNS) relapse have good outcomes when treated with intrathecal and systemic chemotherapy followed by irradiation to the neuroaxis. However, the role of HCT remains unclear for those patients with early isolated CNS relapse (<18 months) or who had high risk disease at diagnosis. We therefore compared the HCT outcomes of 116 children treated at the University of Minnesota from 1991 to 2006 with relapsed ALL involving the CNS alone (CNS, n = 14), the bone marrow alone (BM, n = 85), or both bone marrow and CNS (BM + CNS, n = 17). There were no significant differences among groups in age at diagnosis or transplant, length of first complete remission (CR1), remission status (CR2 versus ≥CR3), graft source, or preparative regimen. The incidence of acute GVHD was similar between groups. Patients with isolated CNS relapse had the lowest cumulative incidence of mortality following transplant (CNS: 0%, BM: 19%, BM + CNS: 29%, P = .03) and relapse (CNS: 0% BM: 30%, BM + CNS: 12%, at 2 years, P = .01) and highest leukemia-free survival (CNS: 91%, BM: 35%, BM + CNS: 46%, P < .01) at 5 years. Risk factors for poor survival were: T cell leukemia or BCR-ABL gene rearrangement, history of marrow relapse, and receipt of HLA-mismatched marrow. These data support the use of allogeneic HCT in the treatment of children with poor prognosis isolated CNS relapse.     

The value of immunohistochemistry for CD14, CD123, CD33, myeloperoxidase and CD68R in the diagnosis of acute and chronic myelomonocytic leukaemias

Rollins‐Raval M A & Roth C G
(2012) Histopathology  60, 933–942 The value of immunohistochemistry for CD14, CD123, CD33, myeloperoxidase and CD68R in the diagnosis of acute and chronic myelomonocytic leukaemias Aims: In the absence of adequate aspirate films and touch imprints, distinction of chronic myelomonocytic leukaemia (CMML) from acute myeloid leukaemia with monocytic differentiation (Mo‐AML) may be difficult solely on the basis of bone marrow biopsy morphological features. The aim of this study was to evaluate the diagnostic utility of a novel immunohistochemical panel for the diagnosis of acute and chronic myelomonocytic leukaemias in bone marrow biopsies. Methods and results: Immunohistochemical labelling for CD14, CD123, CD33, myeloperoxidase (MPO) and CD68R was assessed in 49 myeloid neoplasms with monocytic differentiation (24 CMMLs and 25 Mo‐AMLs) and compared with that of 15 non‐monocytic acute myeloid leukaemias (NM‐AMLs) and 17 non‐neoplastic controls. More than 20% CD14 immunohistochemistry (IHC)+ cells were seen only in Mo‐AMLs and CMMLs, although Mo‐AMLs showed wide variability and overlapped with other categories. More than 20% CD68R IHC+ cells had the highest sensitivity and specificity for Mo‐AML. Discrepant MPO–/CD33+ expression was specific for Mo‐AML but insensitive. A subset of blasts in Mo‐AMLs and NM‐AMLs were weakly CD123+. Conclusions: A significantly increased number of CD14+ cells raises the possibility of a myelomonocytic neoplasm but does not distinguish between CMML and Mo‐AML. Significantly increased numbers of CD68R IHC+ cells and a discrepant MPO–/CD33+ staining pattern are specific for Mo‐AML but are best utilized in a comprehensive panel.     

Long-term outcomes of myeloablation and autologous transplantation of relapsed acute myeloid leukemia in second remission: a British Society of Blood and Marrow Transplantation registry study.

Relapsed acute myeloid leukemia (AML) in adults has a poor prognosis if treated with chemotherapy alone. Case series have previously supported the role of myeloablation and autologous transplantation as a potentially curative treatment. This study aimed to use the large numbers and extended follow-up data in the British Society of Blood and Marrow Transplantation (BSBMT) registry database to establish long-term outcomes and relate these to biological and procedural factors. The BSBMT registry database was used to retrospectively identify 152 adult patients (age, 16-69 years) with AML in second remission treated with autologous transplantation in 1982-2003. Cytogenetic data were available for 68% of the patients; of these, at diagnosis, 42% had good risk features, 57% had standard risk features, and 1% had poor risk features. Conditioning regimens varied; autologous rescue was provided with bone marrow (BM) (71%), peripheral blood stem cells (PBSCs) (18%), or both (11%), which were harvested during first complete remission (CR1) and/or second CR (CR2). Median follow-up was 84 months (range, 2-200 months). At 10 years, actuarial overall survival (OS) was 32%, progression-free survival (PFS) was 28%, and relapse rate (RR) was 57%. The 100-day nonrelapse mortality (NRM) was 7%, rising to 11% at 1 year and to 14% at 10 years. OS was significantly related to M3 subtype (5-year OS, 66%; P = .005), patient age at diagnosis (P = .005) and transplantation (P = .026), and length of CR1, with greatest significance if the patient was dichotomized at CR1 duration of < 8 months or > or = 8 months (P = .0001). There was no difference in OS between regimens containing total body irradiation (TBI) and chemotherapy alone (P = .7). In relation to the nature of autologous graft material, there was improved OS (P = .025) and PFS (P = .009) with the use of cells harvested entirely in CR1 compared with cells harvested in CR2 or in both CR1 and CR2. Engraftment times were significantly shortened with the use of PBSCs alone or in combination with BM compared with BM alone (P = .0001), but there was no significant long-term impact on OS, PFS, RR, or NRM. This study provides long-term follow-up data in one of the largest series of patients with standard-risk and good-risk AML in CR2 treated with autologous transplantation and supports earlier observations that long-term survival is achievable in about 1/3 of patients overall and in about 2/3 of patients with M3 with a relatively low NRM. Outcomes are better in patients with CR1 > or = 8 months by use of grafts obtained entirely in CR1 and use of PBSCs. TBI conditioning did not confer an advantage. Randomized studies against unrelated donor transplantation are warranted.     

Erythroleukaemia in the north of England: a population based study

AIMS: To evaluate the incidence and outcome of acute myeloid leukaemia (AML), FAB M6 (erythroleukaemia). METHODS: A demographic study in the Northern Health Region of England between 1983 and 1999. RESULTS: Thirty three cases were diagnosed and registered prospectively. The overall incidence was 0.077 cases/100,000/year. There was a pronounced rise in incidence in patients aged 56 years or more: 6.6 times higher than that in younger patients. Overall survival was poor; median survival was 11 months for those aged less than 56 years, and three months for patients aged 56 years and above (p = 0.045). Acquired karyotypic abnormalities were found in 17 of 27 patients where analysis was attempted. When classified according to the criteria of the Medical Research Council AML trials, karyotype predicted survival, with a median overall survival of 14 months for those with "standard risk" cytogenetic results and two months for "poor risk" results (p = 0.005). CONCLUSION: This study demonstrates a worse survival for patients with erythroleukaemia than that reported in some published trials of selected patients.     

Common fragile sites in chromosomes of bone marrow cells and peripheral blood lymphocytes from healthy persons and leukemia patients

Frequency and distribution of aphidicolin-induced fragile sites (c-fra) on chromosomes of both peripheral blood lymphocytes (PBL) and bone marrow (BM) from 15 leukemia patients were studied in comparison with 22 PBL and six BM samples from healthy volunteers. In normal controls, the most frequent c-fra was 3p14 in PBL, but it was 4q21-25 in BM. The second most frequent site was 16q23 in PBL, but it was 7q11.2 in BM. These differences in fragile sites between PBL and BM may be related to distinct functions of cells in different tissues. The total number of breaks in PBL and BM showed a significant difference among individuals, but the sites were generally common. The frequency of breaks in PBL from leukemia patients was higher than in controls when the leukemic cells had any karyotypic abnormalities. In leukemia without karyotypic abnormalities and acute myeloid leukemia (AML) with (15:17), the frequency of breaks fell within normal or slightly above normal ranges. Breaks at 3p14 (22.0% of total breaks), 16q23 (7.3%), 7q32 (4.3%), Xp22 (3.7%), and 6q26 (2.9%) were frequent in PBL from seven AML patients. Breaks at 4q21-25 (2.1%), 7q22 (2.2%), 7q32, and Xp22 were more frequently induced than in controls, and 1p32 (0.1%), 3p14, 6q26, and 16q23 were less often expressed than in controls. On the other hand, PBL from acute lymphoblastic leukemia patients showed a higher frequency of breaks only at 1p22 (3.4%) and the frequency of breaks at 3p14 (30.2%) decreased (p less than 0.05). The PBL from AML patients with t(8;21) (q22;q22) showed breaks at 8q22 and 8q24, and the frequencies were significantly higher than those of other types of leukemia or in controls (p less than 0.001). The results of this study suggest that fragility of chromosomes may be related to the chromosomal rearrangement in or predisposition to leukemia.     

Combination of monoclonal antibodies with DST inhibits accelerated rejection mediated by memory T cells to induce long-lived heart allograft acceptance in mice

Plasma cells (PCs) are specialized in antibody (Ab) production and they are, therefore, responsible for maintaining humoral immune responses. The human PC compartment is heterogeneous. PCs from inductive secondary lymphoid organs and from peripheral blood (PB) show less capability for prolonged survival and Ab production than bone marrow (BM) PCs, a pool consisting of fully mature cells. The HLDA9 workshop has allowed the use of labeled-monoclonal Abs (moAbs) recognizing a variety of recently identified lymphocyte modulatory surface receptors. In this study, flow cytometry analysis has been used to define the presence of these receptors on human PCs obtained from human tonsil (as an example of inductive organ), from PB and from BM. It was found that human PCs commonly expressed SLAMF1 (CD150), SLAMF2 (CD48), SLAMF3 (CD229), SLAMF6 (CD352) and SLAMF7 (CD319), but not SLAMF4 (CD244). In addition, PCs distinctively showed a low level of SLAMF5 (CD84) and a very high level of SLAMF7 expression in comparison with earlier stages of B cell maturation. All PC subsets exhibited a similar pattern of expression of SLAMF receptors suggesting a stage-dependent role for these proteins. In addition, most circulating PCs clearly expressed TNFRSF14 (CD270), BTLA (CD272), B7-1 (CD80) and B7-2 (CD86), and a substantial fraction of them were also positive for TNFRSF18 (CD357), FCRL1 (CD307a) and LAIR-1 (CD305). In contrast, tonsil and BM PCs only exhibited partial expression of TNFRSF14 and B7-2, a pattern of molecular expression similar to that detected on germinal center (GC) B cells. Present results indicate that human PCs exhibit a common pattern of SLAMF proteins, but differ in the rest of the receptors examined; this difference might be associated with their distinctive homing and functional requirements.     

Erythropoietic activities in acute leukemia and in malignant lymphoma with or without bone marrow involvement

Erythropoietic activities and immature reticulocyte production were investigated in a total of 157 patients (81 men, 76 women, median age = 42 yr, range = 23 to 65 yr) with acute lymphoid leukemia (ALL, n = 31), acute myeloid leukemia (AML, n = 39), or non-Hodgkin's lymphoma (NHL, n = 87), based on assays of the hemogram, red cell indices, reticulocyte subpopulations, and intramedullary erythroid precursors. There were no significant differences in red blood cell (RBC) counts, blood hemoglobin levels, or erythroid precursors between ALL and AML patients. Reticulocytes in AML patients averaged 1.7 +/- 0.8%, which was higher than in patients with ALL (0.8 +/- 0.3%, p <0.01); the proportion of high-fluorescence reticulocytes (HFR) averaged 4-fold higher in AML versus ALL (p <0.01) and the reticulocyte maturity index (RMI) was higher in AML (20.8 +/- 8.3%) versus ALL (12.4 +/- 6.5%, p <0.01). The RMI was higher in NHL patients with bone marrow (BM) involvement (15.6 +/- 9.4%), compared to those without BM involvement (4.3 +/- 2.1%, p <0.01). The proportion of HFR averaged 11-fold higher in NHL with BM involvement versus NHL without BM involvement. In summary, erythropoietic activity is significantly more active in patients with AML compared to ALL and in patients with NHL with BM involvement, compared to NHL without BM involvement.     

Phenotype of exogenous microparticle-containing pigment cells of the human Peyer’s patch in inflamed and normal ileum

OBJECTIVES: Pigmented cells, that contain inert, submicron-sized dietary particles, are a consistent feature of the base of human Peyer's patches (PP). We aimed (i) to phenotype these intestinal pigment cells (PC) in archival tissue specimens and (ii) to establish whether PC phenotype is altered in inflammatory conditions, especially Crohn's disease (CD). METHODS: PCs contained within PP were identified by routine haematoxylin and eosin (H&E) staining and dark field microscopy of archival ileal sections for: adenocarcinoma (n = 16), colonic CD (n = 23), non-CD colitis (n = 10). Paraffin-embedded serial sections were graded for microscopic inflammation and then investigated immunohistochemically with antibodies against CD68, MAC387, CD14, CD11b, CD15, CD1a, S100, HLA-DR, CD86 and Cathepsin D. Analyses were by light and confocal microscopies. RESULTS: The majority of PCs were CD68 positive (circa 80%) with a minority (circa 20%) staining for MAC387. Microparticles were mainly identified within cathepsin D negative lysosomal compartments. Histological inflammatory grade and disease type had no influence on cell phenotype. CONCLUSIONS: The microparticle-containing PCs of the PP base are mainly mature macrophages (CD68) of low metabolic and immunological activity. There is no evidence of differential PC phenotype or activation in differing disease states, including CD.     

Post-consolidation Immunotherapy with Histamine Dihydrochloride and Interleukin-2 in AML

The initial chemotherapy in acute myeloid leukaemia (AML) comprises a first phase of induction and a second phase of consolidation. In the majority of patients, the induction treatment leads to complete remission (CR), defined as microscopic disappearance of leukaemic disease along with the return of normal haematopoiesis. However, despite the introduction of more efficacious consolidation regimens, a worryingly large proportion of AML patients in CR will subsequently experience relapses with poor prospects of long-term survival. A relapse is assumed to be the result of expansion of residual leukaemic cells that have escaped the initial chemotherapy. The anti-leukaemic functions of T cells and natural killer (NK) cells has formed the background to the use of interleukin-2 (IL-2), a T- and NK cell-activating cytokine, with the aim to eliminate residual leukaemia and hence reduce the relapse rate in AML, but the clinical trials using IL-2 monotherapy have yielded disappointment. A recent phase III study has demonstrated that post-consolidation treatment with the combination of histamine dihydrochloride (HDC) and IL-2 significantly prevents relapse in AML patients. Here we account for the preclinical background to the use of HDC/IL-2 in AML along with a review of clinical results.     

Monitoring TIGIT/DNAM-1 and PVR/PVRL2 Immune Checkpoint Expression Levels in Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia

After allogeneic stem cell transplantation (alloSCT), several immune checkpoints play an important role in the antileukemic immune response in the bone marrow (BM) microenvironment. However, immune checkpoint expression levels in the BM have not been reported after alloSCT in patients with acute myeloid leukemia (AML). We investigated the clinical impact of immune checkpoint expression in BM samples after alloSCT for AML. Higher expression of T cell immunoreceptor with Ig and ITIM domains (TIGIT) was associated with a decreased incidence of acute graft-versus-host disease (P = .048) and poor overall (P = .046) and progression-free survival (P = 0.024). In addition, higher expression of TIGIT at engraftment after alloSCT was correlated with a decreased number of natural killer cells in BM (P = .019). Monitoring TIGIT expression in the BM could be useful for predicting outcome after alloSCT for AML. Our findings raise the possibility that blockade of TIGIT would improve survival.     

Reticulin fibres anchor leukaemic blasts in the marrow of patients with acute lymphoblastic leukaemia

Reticulin fibrosis has been recognized in childhood ALL at diagnosis as part of the altered stromal structure in the bone marrow (BM). Increased fibre density is correlated with a higher concentration of leukaemia cells in the BM and lower numbers of blasts in peripheral blood. We hypothesize that these fibres anchor the leukaemia cells within the BM in close proximity to BM stromal cells (BMSC). The BMSC are a rich source of growth factors and cytokines which enhance leukaemia cell growth and provide protection against chemotherapy. Mobilizing the cells by breaking the ‘anchoring ropes’ could lead to greater exposure to apoptotic signals.     

Differences in CD33 intensity between various myeloid neoplasms

We measured the concentration of CD33 antigen on the surface of cells in 315 bone marrow (BM) samples and 114 corresponding peripheral blood (PB) samples from patients with various leukemias (acute myeloid leukemia [AML], chronic myelogenous leukemia [CML], myeloproliferative disorder [MPD] other than CML, myelodysplastic syndrome [MDS]) and from control subjects. Overall CD33 intensity in total CD33+ cells was significantly higher in BM than in PB. CD33 intensity in total BM CD33+ cells differed significantly with the type of disease. The median number of CD33 molecules per cell was highest in AML, followed by MDS, CML, and control subjects and lowest in MPD. When only CD34+/CD33+ cells were examined, CD33 molecules per cell were highest in CD34+ cells in AML and lowest in MPD (P = .027). Patients with AML or MDS younger than 60 years had significantly higher intensity of CD33 expression on CD34+ cells than patients 60 years or older. Levels of CD33 intensity did not correlate with cytogenetics in patients with AML or MDS. There was no correlation between CD33 intensity and response to therapy or overall survival in 35 patients treated with protocols including Mylotarg. These data demonstrate variation in CD33 intensity between various leukemias.     

Distinct phenotypes of plasma cells in spleen and bone marrow of autoimmune NOD.B10.H2b mice

Long-lived plasma cells (PCs) residing in the bone marrow (BM) are important producers of protective antibodies. However, when reacting against self-antigens, these PCs produce autoantibodies that contribute to progression of autoimmune diseases such as Sj?gren's syndrome (SS). By using a murine model of primary SS, the NOD.B10.H2b mice, we characterized phenotype and generation of PCs at different stages of the pSS disease progression. In general, the PC population found in the NOD.B10.H2b mice expressed high amounts of MHCII, IgG, and BrdU. We further demonstrate the presence of both short- and long-lived PCs in autoimmune spleen and in autoimmune BM. A long-lived PC subset was also found in the spleen and BM of non-autoimmune BALB/c mice, which have not been treated with any immunological agent. Quantitative investigation of splenic and BM PCs revealed that in the NOD.B10.H2 mice, splenic PCs migrate not only to the BM but possibly also to the sites of inflammation. Finally, BM in the aged NOD.B10.H2b mice (40-week-old) presented significantly higher quantities of long-lived PCs than BM of BALB/c mice.