Pre-B acute lymphoblastic leukemia cells may induce T-cell anergy to alloantigen

Even if neoplastic cells express tumor associated antigens they still may fail to function as antigen presenting cells (APC) if they lack expression of one or more molecules critical for the induction of productive immunity. These cellular defects can be repaired by physiologic activation, transfection, or fusion of tumor cells with professional APC. Although such defects can be repaired, antitumor specific T cells may still fail to respond in vivo if they may have been tolerized. Here, human pre-B cell acute lymphoblastic leukemia (pre-B ALL) was used as a model to determine if primary human tumor cells can function as alloantigen presenting cells (alloAPC) or alternatively whether they induce anergy. In the present report, we show that pre-B cell ALL express alloantigen and adhesion molecules but uniformly lack B7-1 (CD80) and only a subset express B7-2 (CD86). Pre-B ALL cells are inefficient or ineffective alloAPC and those cases that lack expression of B7-1 and B7-2 also induce alloantigen specific T- cell unresponsiveness. Under these circumstances, T-cell unresponsiveness could be prevented by physiologic activation of tumor cells via CD40, cross-linking CD28, or signaling through the common gamma chain of the interleukin-2 receptor on T cells. Taken together, these results suggest that pre-B ALL may be incapable of inducing clinically significant T-cell-mediated antileukemia responses. This defect may be not only due to their inability to function as APC, but also due to their potential to induce tolerance. Attempts to induce clinically significant antitumor immune responses may then require not only mechanisms to repair the antigen presenting capacity of the tumor cells, but also reversal of tolerance.     

Platelet-melanoma cell interaction is mediated by the glycoprotein IIb- IIIa complex

A human malignant melanoma cell line (M3Dau) was observed by electron microscopy to interact directly with human platelets and induced platelet aggregation. Fab fragments of a monoclonal antibody MoAb (LYP18), directed against the platelet glycoprotein (GP) IIb-IIIa complex, inhibited platelet-melanoma interactions and platelet-platelet aggregation. M3Dau melanoma cells bind LYP 18 and synthesize IIb-IIIa- like GPs. When the melanoma cells were preincubated with LYP 18, tumor- platelet interaction did not occur, suggesting that the interaction may be mediated by the IIb-IIIa-like GPs present on the melanoma cell surface. Glanzmann's thrombasthenic platelets, lacking GPIIb and IIIa, did not interact with melanoma cells, indicating that the platelet GPIIb-IIIa complex is also necessary for the platelet-melanoma cell interaction. This work demonstrates the importance of the IIb-IIIa-like GPs, present on M3Dau melanoma cells, in mediating tumor-platelet interactions.     

p16 gene homozygous deletions in acute lymphoblastic leukemia

The p16 protein is a cyclin inhibitor encoded by a gene located in 9p21, which may have antioncogenic properties, and is inactivated by homozygous p16 gene deletion or, less often, point mutation in several types of solid tumors often associated to cytogenetic evidence of 9p21 deletion. We looked for homozygous deletion and point mutation of the p16 gene in acute lymphoblastic leukemia (ALL), where 9p21 deletion or rearrangement are also nonrandom cytogenetic findings. Other hematologic malignancies including acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), chronic lymphocytic leukemia (CLL), and myeloma were also studied. Homozygous deletion of the p16 gene was seen in 9 of the 63 (14%) ALL analyzed, including 6/39 precursor B-ALL, 3/12 T-ALL, and 0/12 Burkitt's ALL. Three of the 7 ALL with 9p rearrangement (including 3 of the 5 patients where this rearrangement was clearly associated to 9p21 monosomy) had homozygous deletion compared to 5 of the 55 patients with normal 9p (the last patient with homozygous deletion was not successfully karyotyped). Single stranded conformation polymorphism analysis of exons 1 and 2 of the p16 gene was performed in 88 cases of ALL, including the 63 patients analyzed by Southern blot. Twenty-six of the cases had 9p rearrangement, associated to 9p21 monosomy in at least 12 cases. A missense point mutation, at codon 49 (nucleotide 164), was seen in only 1 of the 88 patients. No homozygous deletion and no point mutation of the p16 gene was seen in AML, MDS, CLL, and myeloma. Homozygous deletion of interferon alpha genes (situated close to p16 gene in 9p21) was seen in only 3 of the 9 ALL patients with p16 gene homozygous deletion, and none of the ALL without p16 gene homozygous deletion. Our findings suggest that homozygous deletion of the p16 gene is seen in about 15% of ALL cases, is not restricted to cases with cytogenetically detectable 9p deletion, and could have a pathogenetic role in this malignancy. On the other hand, p16 point mutations are very rare in ALL, and we found no p16 homozygous deletions or mutations in the other hematologic malignancies studied.     

Additive effect of erythropoietin and heme on murine hematopoietic recovery after azidothymidine treatment [see comments]

The ability of combination treatment with erythropoietin (Epo) and heme to rescue hematopoietic activity in mice from the suppressive effect of azidothymidine (AZT) was determined. Exposure of mice to AZT for 5 weeks produced marked anemia, thrombocytopenia, neutropenia, and weight loss, whereas mice that received Epo and heme for 3 subsequent weeks showed significant alleviation of AZT cytotoxicity. Treatment with Epo (10 U for 5 times/week) stimulated hematopoietic recovery in the AZT- treated animals and reduced the severe anemia and thrombocytopenia by 3 weeks. Administration of a lower Epo dose (1 U Epo) resulted in only a modest retardation of AZT-induced anemia, although, when combined with heme, there was a great improvement in recovery of erythropoiesis. The combination of heme with Epo (10 U) produced the optimum response, resulting in almost normal recovery of bone marrow cellularity as well as recovery of burst-forming units-erythroid (BFU-E) and splenic hematopoietic progenitor content (colony-forming unit-spleen [CFU-S]) by the end of 3 weeks of post-AZT treatment. Treatment with heme alone markedly enhanced the recovery of BFU-E and CFU-S, as well as body weight post-AZT; however, this recovery was not to the extent seen in combination with Epo (10 U). Long-term bone marrow cultures (LTBMCs) established from mice exposed to AZT for 8 weeks showed a marked reduction in cellularity and this was completely alleviated when mice received heme and Epo (10 U) for 3 weeks after 5 weeks of AZT administration. The additive effect of heme and Epo was seen in BFU-E production, as well as in CFU-S production, in LTBMCs. Thus, heme exerts a significant protective effect on hematopoietic progenitors in vivo and may be of potential clinical use in combination with Epo to promote effective erythropoiesis in the setting of AZT therapy.     

Predictive value for treatment outcome in acute myeloid leukemia of cellular daunorubicin accumulation and P-glycoprotein expression simultaneously determined by flow cytometry

To evaluate the clinical relevance of multidrug resistance (MDR) phenotype, the intracellular daunorubicin accumulation (IDA) and P- glycoprotein (P-gp) expression were investigated in 87 adult patients with acute leukemia: 69 patients with de novo acute myeloid leukemia (AML), 10 with AML at relapse, and eight with secondary leukemia to myelodysplastic syndromes (MDS-AML). IDA and P-gp expression were determined by double-labeling flow cytometry analysis. Of 87 patients, 36 expressed P-gp (41%). P-gp expression was more frequently observed in AML at relapse and MDS-AML as compared with de novo AML (P = .0001). P-gp expression was significantly associated with CD34 expression (P = .0003) and chromosome 7 abnormalities (P = .027). A significantly reduced IDA was observed in P-gp+ as compared with P-gp- patients (P = .0007). Of the 87 patients, 51 achieved complete remission (CR). A reduced IDA was observed in patients in failure as compared with patients in CR (22% +/- 17% v 42% +/- 21%; P = 10(-4). Twelve of 36 P- gp+ patients as compared with 40 of 51 P-gp- patients achieved CR (33% v 78%; P = 10(-4). The prognostic value of IDA and P-gp expression was confirmed in multivariate analysis. These data suggest that the determination of IDA and P-gp expression may be useful in designing therapy for patients with AML.     

Seven-day proton pump inhibitor, amoxicillin and clarithromycin triple therapy. factors that influence Helicobacter pylori eradications success.

AIM: To evaluate which factors influence eradication success with standard triple therapy for Helicobacter pylori. PATIENTS AND METHODS: A prospective study was made of 891 patients infected by H. pylori and diagnosed with duodenal ulcer (n=422), gastric ulcer (n=221), or functional dyspepsia (n=248). Initially, an endoscopy with biopsies of antrum and body (haematoxylin-eosin stain), and a 13C-urea breath test were performed. All patients were treated for seven days with either omeprazole 20 mg twice daily in 442 patients (OCA) or pantoprazole 40 mg twice daily in 449 patients (PCA), associated to clarithromycin (500 mg twice a day) and amoxicillin (1 g twice a day). Two months after completing therapy urea breath test was repeated to confirm eradication. RESULTS: Mean age +/- SD was 51.6 +/- 15 years, 61% were male. Overall eradication rate was 73.7% (95% CI 69-77%) and 80.8% (77-84%) with OCA and PCA therapy, respectively, showing significant difference between treatment regimens (chi 2 =6.3; p= 0.01). As refers to underlying diseases, H. pylori eradication was achieved in 77.4% (74-80%) of peptic ulcers and 77% (71-82%) of functional dyspepsia (p=n.s.). With our two treatment regimens (OCA/PCA) eradication success was 74/81% in peptic ulcer (p=0.03), and 72/80% in functional dyspepsia (p=0.1). In the multivariate analysis, type of therapy was the only variable that correlated with eradication success (odds ratio 1.5; 95% CI: 1.1-2.1) (chi2 model: 6,4; p=0.01). CONCLUSIONS: Standard triple therapy containing a proton pump inhibitor, clarithromycin and amoxicillin for seven days achieves in our community a moderate eradication success; this result could improve by using pantoprazole instead of omeprazole. This therapy is equally effective in patients with peptic ulcer and functional dyspepsia.     

Cancer characteristics in Swedish families fulfilling criteria for hereditary nonpolyposis colorectal cancer

BACKGROUND & AIMS: The present study quantified the prevalence of families that fulfill the Amsterdam or Bethesda criteria for hereditary nonpolyposis colorectal cancer (HNPCC) in the whole Swedish population and investigated the extent to which tumors in the classified families are HNPCC-related. METHODS: The families of the Swedish Family-Cancer Database with at least 4 generations (N = 566,877) were classified according to the Amsterdam and the Bethesda criteria. Survival methods were used to assess the risk of cancer in the classified families, the prognosis of cancer patients, and the risk of subsequent malignancies after colorectal adenomas and after colorectal/endometrial adenocarcinomas. RESULTS: The Bethesda criteria identified 0.9% of all Swedish families and 11.2% of patients with colorectal cancer. Families that fulfilled the Bethesda criteria showed increased risks of cancer in the colorectum, endometrium, small bowel, ovary, stomach, bile ducts, renal pelvis, and ureter; members of Bethesda criteria families were at decreased risks of lung and cervical cancers. The prognosis of cancer in the ureter, renal pelvis, stomach, ovary, and colorectum, but not in the endometrium, was better in Bethesda criteria than in nonclassified families. CONCLUSIONS: Most malignancies in the classified families reflect typical features of HNPCC (association with subsequent malignancies, accelerated adenoma-carcinoma sequence, and better survival). The data presented in this study should help to define surveillance strategies for members of families that fulfill the criteria for HNPCC testing.