Intermediate dose recombinant interferon-alpha as second-line treatment for patients with recurrent cutaneous melanoma who were pretreated with low dose interferon

BACKGROUND

Interferon (IFN) is widely considered the most effective agent in the adjuvant therapy of patients with cutaneous melanoma (CM). However, little is known about the effect of IFN on pretreated CM patients who experience disease recurrence. The authors conducted a Phase II study to determine whether intermediate doses of IFN could be beneficial for these patients.

METHODS

A series of 24 consecutive CM patients who had undergone surgery for local, in-transit, or lymph node disease recurrence during adjuvant therapy with low dose IFN (IFNalpha-2b, 3 million units [MU] per day, three times per week) were enrolled for second-line therapy with intermediate dose IFN (IFNalpha-2b, 10 MU per day) for one year.

RESULTS

IFN was discontinued in 7 patients (29.2%) because of toxicity. Several patients complained of impairment in their daily activities. Progression of disease was registered in 17 patients (70. 8%), with a median disease free survival of 5.5 months (95% confidence interval, 3.4-14.2). The median follow-up for the 7 patients who did not experience disease recurrence was 15 months (range, 13-22 months).

CONCLUSIONS

An increased dose of IFN as second-line adjuvant treatment was poorly tolerated and produced negative clinical outcomes in patients with CM. However, these patients probably were unresponsive to IFN regardless of the dosage level. In fact, the first adjuvant IFN treatment was ineffective in all patients. Thus, the key factor in the treatment of CM seems to be patient responsiveness to IFN rather than the total dosage achieved.

Human dbl proto-oncogene in 85 kb of xq26, and determination of the transcription initiation site

The dbl oncogene is generated by substitution of the 5' portion of its normal counterpart with an unrelated human sequence. To analyze the genomic structure and transcriptional regulation of the dbl proto-oncogene, we have isolated human genomic clones containing the entire human proto-dbl gene, localized in Xq26. Restriction mapping of a 600kb YAC clone (yWXD311) placed proto-dbl about 50kb telomeric to the coagulation Factor IX gene. The genomic DNA fragment containing the 5' end of proto-dbl was subcloned into plasmid vectors and the nucleotide sequences of exon 1, the flanking intronic region and genomic DNA 5' of the first codon were determined. Sequence analysis of 85119bp from the region revealed the genomic structure of proto-dbl. It contains 25 exons coding for a 4.7kb transcript including large 5'- and 3'- (1218bp and 701bp, respectively) untranslated regions (UTRs). RNase protection and primer extension assays on RNA from medullary thyroid carcinoma (TT) cells, which normally express dbl, revealed a transcription start site 1218bp upstream of the ATG of the first exon. A 1.6kb genomic 5' of the translation start sites drives the expression of a CAT-reporter in transient transfections in the TT cell line, though lacking TATA or CAAT boxes.

Serum ECP and MPO are increased during exacerbations of chronic bronchitis with airway obstruction

Many studies have demonstrated that, in asthma, serum levels of eosinophil cationic protein (ECP) are related to the activity and severity of the disease and can be used to evaluate the response to steroid treatment. During exacerbations of chronic bronchitis, airway inflammation shows some features of asthmatic inflammatory processes, with recruitment of eosinophils and recovery of significant amounts of ECP in bronchial lavage fluid (BAL). Involvement of neutrophils, with high levels of myeloperoxidase (MPO), is, on the contrary, typical of this latter disease, and not shared with asthma. In spite of the information collected with BAL and bronchial biopsy studies, few data still exist on serum levels of these proteins in chronic bronchitis. The objective of this study was to assess if serum levels of ECP and MPO are specifically increased in exacerbations of chronic bronchitis, as compared to other non-asthmatic acute respiratory disturbances. Serum ECP, MPO and immunoglobulin E (IgE) levels were measured in 17 non-atopic patients with exacerbation of chronic bronchitis with airway obstruction (COPD) and in 11 control subjects seeking emergency medical treatment for unrelated acute respiratory problems. Spirometry was performed in patients able to give the necessary collaboration. All the subjects of this study were recruited from the emergency department. Both ECP and MPO were significantly increased in serum from patients with exacerbated COPD (22.2 +/- 4.1 vs 9.5 +/- 1.4 mcg/L and 853 +/- 168 vs 375 +/- 41 mcg/L) and a strong correlation existed between these two variables (r = 0.782). A further control group was made of 11 patients with stable COPD. These subjects had levels of both ECP (13.1 +/- 2.7 mcg/L) and MPO (469 +/- 71) significantly lower than patients with exacerbated disease and higher than those without COPD. We conclude that serum ECP and MPO are increased during the exacerbations of COPD. These observations can give a basis for further studies aimed to evaluate the utility of these two proteins as markers of activity and severity of COPD.

Sensitivity and specificity of epiluminescence microscopy: evaluation on a sample of 2731 excised cutaneous pigmented lesions. The Melanoma Cooperative Study

To evaluate the role of epiluminescence microscopy (ELM) in the differential diagnosis of cutaneous pigmented lesions, and to improve the early diagnosis of cutaneous malignant melanoma (CMM), 15,719 pigmented lesions from 8782 consecutive patients were evaluated using ELM with a hand-held video microscope imaging system (MS 500B Micro-Scopeman, Moritex). Comparison between risk levels as inferred from ELM screening and histology was performed on 2731 surgically excised lesions. ELM sensitivity, specificity, positive and negative predictive values, as well as agreement with histological results for the different subgroups of lesions, were determined. Overall agreement was 87.3% (ranging from 85.1% to 92.2% for melanocytic and non-melanocytic lesions, respectively); sensitivity and specificity were high (values ranging from 87.3% to 96.3% among different subsets of ELM-analysed lesions) and statistically significant (P < 0.0001). ELM screening identified 165 new cases of CMM with a high proportion of lesions (115; 70%) in an early phase of tumour growth (Breslow thickness </= 1.5 mm). Thus, ELM is helpful to the clinician in deciding which pigmented lesions need surgical excision, as well as in diagnosing early CMM lesions.

Manganese peroxidase isoenzymes produced by Pleurotus ostreatus grown on wood sawdust

The white rot basidiomycete Pleurotus ostreatus produces two manganese peroxidase (MnP) isoenzymes when grown in solid stationary conditions on poplar sawdust, whereas a lower production of these same enzymes is observed on fir sawdust. Addition of Mn(2+) to poplar culture resulted in a threefold increase of MnP activity; the same addition to fir culture was able to increase tenfold the MnP production. The two MnP isoenzymes (MnP2 and MnP3) were purified from P. ostreatus poplar culture. The isoenzymes differ in their pI values, molecular masses, and N-terminal sequences. MnP3 has the same N-terminal sequence as that of a P. ostreatus MnP previously reported. Both isoenzymes exhibit Mn(2+)-dependent and Mn(2+)-independent peroxidase activities when tested on phenolic substrates. The gene coding for the new isoenzyme MnP2 was cloned and sequenced and the promoter region analyzed. Furthermore, the chromosomal localization of all known P. ostreatus genes was determined.

Copper induction of laccase isoenzymes in the ligninolytic fungus Pleurotus ostreatus

Pleurotus ostreatus is a white rot basidiomycete that produces several extracellular laccase isoenzymes, including phenol oxidase A1b (POXA1b), POXA2, and POXC. POXC was the most abundant isoenzyme produced under all of the growth conditions examined in this study. Copper was the most efficient inducer of laccase activity among the putative inducers tested. The amounts of all of the previously described laccase isoenzymes increased substantially in copper-supplemented cultures. Under these conditions expression of POX isoenzymes was regulated at the level of gene transcription. It is worth noting that poxa1b mRNA was the most abundant induced transcript at all of the growth times analyzed, and the amount of this mRNA increased until day 7. The discrepancy between the poxa1b transcript and protein amounts can be explained by the presence of a high level of the protein in P. ostreatus cellular extract, which indicated that the POXA1b isoenzyme could be inefficiently secreted and/or that its physiological activity could occur inside the cell or on the cell wall. Moreover, the POXA1b isoenzyme behaved uniquely, as its activity was maximal on the second day of growth and then decreased. An analysis performed with protease inhibitors revealed that the loss of extracellular POXA1b activity could have been due to the presence of specific proteases secreted into the copper-containing culture medium that affected the extracellular POXA1b isoenzyme.

Evaluation of polyamide synthetic hair. A long-term clinical study

BACKGROUND

Different methods of hair restoration surgery exist: expanders, rotation flaps, autotransplantation and artificial hair implant.

METHODS

The authors reviewed 196 patients who underwent hair implantation 2 years before with a highly biocompatible polyamide fiber. Indications, contraindications and complications of the procedure are outlined.

RESULTS

Clinical subjective and photographic objective judgement, evaluation of Hamilton scale grading and covered area rate show very satisfactory improvements. Relevant adverse events were limited to 1.02%.

CONCLUSIONS

A careful medical follow-up with regular scalp check-up minimizes complications to a very acceptable rate and overall results are definitely satisfying.

Hyperfibrinogenemia is associated with specific histocytological composition and complications of atherosclerotic carotid plaques in patients affected by transient ischemic attacks

BACKGROUND

Epidemiological studies have demonstrated that hyperfibrinogenemia is an independent risk factor for cerebrovascular atherosclerosis. However, the underlying mechanisms are poorly understood. We studied whether hyperfibrinogenemia could modify the histological composition of atherosclerotic plaque and precipitate carotid thrombosis resulting from rupture of the plaque.

METHODS AND RESULTS

We studied the histological composition of 71 carotid atherosclerotic plaques from patients who had undergone surgical endarterectomy after a first episode of transient ischemic attack. Patients were divided into 3 groups corresponding to the tertiles of plasma fibrinogen values. Hypercholesterolemia, hypertriglyceridemia, hypertension, diabetes, and smoking habit were also assessed. At the histological analysis, plaques of patients in the highest tertile of fibrinogen (>407 mg/dL) were characterized by a high incidence of thrombosis (66.7% of cases) compared with plaques of subjects in the lower (21.7%) (P=0.002) and middle (29. 2%) (P=0.009) tertiles. Plaque rupture was significantly associated with high fibrinogen levels (54.2%, P=0.003). Multivariate logistic regression indicated that hyperfibrinogenemia was an independent risk factor for a decrease in cap thickness (P=0.0005), macrophage foam cell infiltration of the cap (P=0.003), and thrombosis (P=0. 003). When the presence of other risk factors was accounted for, hyperfibrinogenemia remained an independent predictor of carotid thrombosis with an odds ratio of 5.83, compared with other risk factors.

CONCLUSIONS

The results of the present study add to the evidence that hyperfibrinogenemia, independently of other risk factors, is associated with a specific histological composition of carotid atherosclerotic plaques that predisposes them to rupture and thrombosis.

Identification of a founder BRCA2 mutation in Sardinia

Sardinian population can be instrumental in defining the molecular basis of cancer, using the identity-by-descent method. We selected seven Sardinian breast cancer families originating from the northern-central part of the island with multiple affected members in different generations. We genotyped 106 members of the seven families and 20 control nuclear families with markers flanking BRCA2 locus at 13q12-q13. The detection of a common haplotype shared by four out of seven families (60%) suggests the presence of a founder BRCA2 mutation. Direct sequencing of BRCA2 coding exons of patients carrying the shared haplotype, allowed the identification of a 'frame-shift' mutation at codon 2867 (8765delAG), causing a premature termination-codon. This mutation was found in breast cancer patients as well as one prostate and one bladder cancer patient with shared haplotype. We then investigated the frequency of 8765delAG in the Sardinian breast cancer population by analysing 270 paraffin-embedded normal tissue samples from breast cancer patients. Five patients (1.7%) were found to be positive for the 8765delAG mutation. Discovery of a founder mutation in Sardinia through the identity-by-descent method demonstrates that this approach can be applied successfully to find mutations either for breast cancer or for other types of tumours.

CD69-triggered ERK activation and functions are negatively regulated by CD94 / NKG2-A inhibitory receptor

CD69 represents a functional triggering molecule on activated NK and T cells, capable of inducing cytotoxic activity and costimulating cytokine production. It belongs to the C-lectin type superfamily, and its gene maps in the NK gene complex, close to other genes coding for NK receptors. CD94 / NKG2-A complex is the inhibitory receptor for the non classical MHC class I molecule HLA-E on human NK cells. To investigate CD69-initiated signal transduction pathways, and to evaluate CD94 / NKG2-A interference on CD69 triggering ability, we have generated transfectants expressing both receptors in the RBL cell line. Here we report that CD69 engagement leads to the activation of extracellular signal-regulated kinase (ERK) enzymes belonging to the MAPK family, and that this event is required for CD69-mediated cell degranulation. Moreover, we show that the co-engagement of CD94 / NKG2-A inhibitory receptor effectively suppresses both CD69-triggered cell degranulation in RBL transfectants, through the inhibition of ERK activation, and CD69-induced cytotoxicity in human NK cells. Thus, here we provide new information on the molecular mechanisms initiated by CD69 activation receptor, and show that CD69-initiated signaling pathways and functional activity are negatively regulated by CD94 / NKG2-A inhibitory complex.

CEOP-B/VIMB vs. promace-CytaBOM in the treatment of intermediate or high grade non-Hodgkin's lymphoma: A randomised multicenter study of Southern Italy Cooperative Group

From January 1992 to December 1995, 129 patients with previously untreated non-Hodgkin's lymphoma were randomised in a phase III multicenter trial to receive CEOP-B/VIMB or ProMACE-CytaBOM. Eligibility criteria included intermediate or high grade lymphoma (follicular large cell, diffuse small cleaved-cell, diffuse mixed, diffuse large-cell and immunoblastic) with an Ann Arbor stage II bulky, III or IV. All patients entered into the study were considered evaluable according to intent to treat analysis. At a median follow-up of 60 months there were no significant differences between the treatment response rates [82% (60%CR) for CEOP-B/VIMB vs. 81% (69% CR) for ProMACE-CytaBOM]. Conversely, with regard to disease-free survival, a significant difference was observed between the two treatment arms (42% for CEOP-B/VIMB vs. 24% for ProMACE-CytaBOM at 5 years; p=0.046). However, this difference did not translate in a significant difference in overall survival (45% vs. 39% at 5 years). Moreover, when response rates and outcome were analysed for different prognostic subgroups according to International Prognostic Index, no significant differences were observed between the treatment groups. It is important to note that neither regimen was able to improve outcome of poor risk patients who fared badly with both treatments (median survival 9 and 8 months respectively). Toxicity was also similar in both treatments with grade 3-4 leukopenia observed in 39% and 47% of cases and grade 3-4 thrombocytopenia in 24% and 27% of cases respectively. In conclusion, in this study CEOP-B/VIMB was not superior to ProMACE-CytaBOM in aggressive lymphomas and the alternating strategy failed to improve outcome of poor risk patients in which newer more aggressive treatments are needed.

Interferon alpha-2b at low doses as long-term antiangiogenic treatment of a metastatic intracranial hemangioendothelioma: a case report

We describe a case of intracranial haemangioendothelioma in a 20-year old female patient who presented severe neurological symptoms and relapsed after two surgical interventions. The patient was treated with low doses of recombinant interferon alpha-2b (1 MUI three times a week) after surgical resection which led to recovery of daily function and work activity. To our knowledge, this is the ninth patient reported with intracranial hemangioendothelioma, but the only one having diffuse and painful bone metastases resolved by treatment with interferon. After 30 months the patient is free from symptoms and recurrence. The effectiveness shown by recombinant interferon alpha-2b against vascular neoplasms prompted us to look for the possible biological basis of such a property.

Immunological findings in thymoma and thymoma-related syndromes

Human thymoma is a neoplasm of thymic epithelial cells associated with several clinical syndromes ranging from autoimmune disease to immunodeficiency. The aim of our research was to investigate T cell-mediated immune response in patients with thymoma. Initially eight patients were enrolled in this study. Four patients underwent surgical removal of the thymus, while four were submitted to diagnostic procedures only. Inversion of the CD4:CD8 ratio was found in three patients. Only one subject displayed a normal CD19 count in peripheral blood. The mean value (+/-SD) of the CD19 percentage in the patient group was 2 +/- 2.2. Notably, the patients with thymoma had fewer mature B lymphocytes than the thymectomized patients. The T-cell receptor (TCR) repertoire was investigated in three individuals affected by thymoma: one underwent thymectomy, while the two others, one of which presented with lymphocytosis, were submitted to diagnostic biopsies only. The preliminary results showed a marked alteration in the CD8 repertoire of the thymectomized patient but not in that of the lymphocytotic patient. However, alterations in the TCR repertoire were also found in one patient with thymoma. Altogether, these preliminary findings reveal that loss of CD19+ lymphocytes in peripheral blood is a frequent phenomena in thymoma patients. In this article we discuss this aspect in the context of alterations of the TCR repertoire.

Role of somatostatin analogue-based therapy in unresponsive malignant thymomas

Thymomas are rare neoplasms that are usually associated with parathymic syndromes, pure red cell aplasia, myasthenia gravis, hypogammaglobulinaemia and other mainly immunological disorders. Therefore, the management of thymoma patients is often complex and presents many diagnostic and therapeutic issues. Controversies concerning the definition of the histological subtypes and the role played by thymoma-associated syndromes are of primary importance in determining the oncological approach. Although low-stage thymomas have a high percentage of recovery, thymomas which are locally advanced, metastatic or previously treated with standard therapeutic options have no well-defined and effective treatment approaches. The data previously described by us on somatostatin receptor scintigraphy showing high uptake of indium-labelled octreotide by thymic masses and the successful treatment of a patient with thymoma and pure red cell aplasia with octreotide and prednisone has provided us the rationale for using such treatment in patients with advanced thymoma.

Role of surgery in thymic disorders

Thymomas are relatively slow-growing neoplasms that should be considered malignant tumours. When treated in the early stages, however, they have an excellent prognosis for long-term survival. Surgery, radiation therapy and chemotherapy all play a role in the management of these neoplasms. Surgery is the treatment of choice in thymoma patients and has become an increasingly accepted procedure in the treatment of myasthenia gravis (MG) since 1936, when thymectomy was performed for this disease for the first time. Improvement in myasthenic symptoms is nearly always observed following thymectomy, but the rates of complete remission vary from 7% to 63%. We have studied the potential preoperative factors predicting the evolution of MG.

On the presence of ganglion cells in the intracranial portion of the accessory nerve (XI cranial nerve) in some mammals

The intracranial tract of the accessory nerve (XI cranial nerve) was studied in some mammals (equines, domestic and wild ruminants, pig, carnivores, rabbit, nutria, guinea pig, hamster, hedgehog). The specimens were embedded in paraffin or paraplast, the sections were stained with cresyl violet, haematoxylin and eosin, or submitted to argentic impregnation. Pseudounipolar ganglion cells were found in all the mammals examined, with the exception of the cat. The number of cells and their variability in the different species and subjects were related. The topography and morphology of the cells were described. This comparative study has demonstrated that the accessory nerve is not a entirely motor nerve, but it is a mixed, motor and sensitive, nerve. Nevertheless, we think further studies are necessary in order to establish the peripheral distribution, the central pathway and the functional role of the pseudounipolar neurons found in the intracranial tract of the accessory nerve.

Functional imaging of thymic disorders

Human thymomas are rare tumours which usually develop in the chest. The diagnosis via guided biopsy, the evaluation of the extent of the tumour and its boundaries with adjacent organs, the choice of the appropriate therapeutic option, and the assessment of response to treatment are usually made with computed tomography (CT) alone or in combination with magnetic resonance imaging (MRI). More recently, radiopharmaceuticals and nuclear medicine procedures have been used increasingly in the imaging and functional characterization of benign and malignant thymic disorders. Two groups of radiopharmaceuticals have been used. The first includes several oncotropic tracers, such as 201Tl-chloride, 99mTc-sestamibi and 18F-fluorodeoxyglucose, which are significantly concentrated in thymic tumours. Their uptake correlates with tumour grades and cellularity. The second class includes two radioligands: [(111)In-DTPA-D-Phe1]-octreotide (DTPA, diethylenetriamine penta-acetic acid) and [(111)In-DTPA-Arg1]-substance P, which bind to specific receptors. [(111)In-DTPA-Arg1]-substance P binds to its receptors that are largely expressed in the thymus of patients with autoimmune diseases. [(111)In-DTPA-D-Phe1]-octreotide recognizes the somatostatin receptor subtype 2. In patients with active disease investigated in our institution [(111)In-DTPA-D-Phe1]-octreotide has been shown to concentrate in the majority of thymoma deposits. Conversely, it is not concentrated in adult patients with benign lymphofollicular thymic hyperplasia. This finding has had a significant impact on the management of patients with myasthenia gravis as it differentiates early-stage thymoma from benign hyperplasia, unlike CT and MRI, which often fail to distinguish between the two. In addition to its role in diagnostic imaging, somatostatin receptor scintigraphy also enables us to select patients with advanced or metastatic thymoma unresponsive to conventional therapies, who might benefit from a somatostatin analogue-based treatment, serving thus as a link between diagnosis and therapy. In this article, we discuss and analyse the results of functional imaging with different radiopharmaceuticals, primarily those that we have obtained with [(111)In-DTPA-D-Phe1]-octreotide.

One-year pilot study on tauroursodeoxycholic acid as an adjuvant treatment after liver transplantation

BACKGROUND

The usefulness of ursodeoxycholic acid after liver transplantation is controversial. Tauroursodeoxycholic acid, the natural taurine-amidate, is a highly hydrophilic and cytoprotective bile salt currently under investigation.

AIMS

To investigate the clinical usefulness of tauroursodeoxycholic acid after liver transplantation.

PATIENTS

Thirty-three patients undergoing liver transplantation entered the study.

METHODS

Sixteen patients were randomized to receive tauroursodeoxycholic acid (250 b.i.d. for 12 months) and 17 served as controls. Tauroursodeoxycholic acid was given from day 5 after transplantation for one year.

RESULTS

Tauroursodeoxycholic acid treatment was safe and well tolerated. No drop outs occurred. Among the 29 patients undergoing long-term follow-up, five deaths occurred (3 of whom in the tauroursodeoxycholic acid group), none of which was related to treatment. The one-year actuarial survival was 78.6% in patients treated with tauroursodeoxycholic acid and 86.7% in controls (n.s.). No differences were observed with respect to early or late graft function and survival, nor to acute cellular rejection. Tauroursodeoxycholic acid therapy was associated with lower serum cholesterol levels (p < 0.02) during the early postoperative months; with milder cholestasis; with a drop in biliary cholates but no changes in endogenous hydrophobic bile salts.

CONCLUSIONS

Long-term treatment with low dose tauroursodeoxycholic acid after liver transplantation is safe but does not affect graft function and survival.

Protein and gene structure of a blue laccase from Pleurotus ostreatus1

A new laccase isoenzyme (POXA1b, where POX is phenol oxidase), produced by Pleurotus ostreatus in cultures supplemented with copper sulphate, has been purified and fully characterized. The main characteristics of this protein (molecular mass in native and denaturing conditions, pI and catalytic properties) are almost identical to the previously studied laccase POXA1w. However, POXA1b contains four copper atoms per molecule instead of one copper, two zinc and one iron atom per molecule of POXA1w. Furthermore, POXA1b shows an unusually high stability at alkaline pH. The gene and cDNA coding for POXA1b have been cloned and sequenced. The gene coding sequence contains 1599 bp, interrupted by 15 introns. Comparison of the structure of the poxa1b gene with the two previously studied P. ostreatus laccase genes (pox1 and poxc) suggests that these genes belong to two different subfamilies. The amino acid sequence of POXA1b deduced from the cDNA sequence has been almost completely verified by means of matrix-assisted laser desorption ionization MS. It has been demonstrated that three out of six putative glycosylation sites are post-translationally modified and the structure of the bound glycosidic moieties has been determined, whereas two other putative glycosylation sites are unmodified.

[An experimental study of the use of synthetic meshes in large abdominal eventrations]

BACKGROUND

The aim of this study is to evaluate the biocompatibility of Angimesh mesh (polypropilene) in rats, usually used to replace or to strengthen the abdominal fasciae.

METHODS

We made an abdominal longitudinal incision of skin and muscles in 20 rats was carried out and two muscular semilunae removed. The incision was occluded with Angimesh mesh fixed by ethilcyanoacrilate glue (first group of rats) or with suture stitches (second group of rats). The animals were sacrificed after 80 days and the stability of the mesh and the presence of endoperitoneal adhesion were evaluated macroscopically, and microscopically the fibrogenesis and inflammation answer.

RESULTS

Two rats of the first group and seven of the second group died before 30 days. The mesh was more steady when fixed by suture. Adhesion in the contact sites between the mesh and the peritoneum was found. Histology did not show any inflammation reaction but showed a fibrogenic answer.

CONCLUSIONS

The cyanoacrilate non-toxicity has been confirmed also in this application. Angimesh mesh showed good biocompatibility and resulted ideal for the synthesis of large abdominal resections.

CD94/NKG2-A inhibitory complex blocks CD16-triggered Syk and extracellular regulated kinase activation, leading to cytotoxic function of human NK cells

The CD94/NKG2-A complex is the inhibitory receptor for the nonclassical MHC class I molecule HLA-E on human NK cells. Here we studied the molecular mechanisms underlying the inhibitory activity of CD94/NKG2-A on NK cell functions by analyzing its interference on CD16-initiated signaling pathways involved in the control of cytolytic activity. Both tyrosine phosphorylation and activation of Syk kinase together with tyrosine phosphorylation of CD16 receptor zeta subunit are markedly inhibited by the coengagement of CD94/NKG2-A complex. As a downstream consequence, CD94/NKG2-A cross-linking impairs the CD16-induced activation of extracellular regulated kinases (ERKs), a pathway involved in NK cytotoxic function. The block of ERK activation is exerted at an early, PTK-dependent stage in the events leading to p21ras activation, as the CD16-induced tyrosine phosphorylation of Shc adaptor protein and the formation of Shc/Grb-2 complex are abrogated by CD94/NKG2-A simultaneous engagement. Our observations indicate that CD94/NKG2-A inhibits the CD16-triggered activation of two signaling pathways involved in the cytotoxic activity of NK cells. They thus provide molecular evidence to explain the inhibitory function of CD94/NKG2-A receptor on NK effector functions.

A pilot study on the safety and effectiveness of immunosuppression without prednisone after liver transplantation

BACKGROUND

Corticosteroids are commonly used in the immunosuppression therapy after liver transplantation, yet are associated with considerable side effects. Retrospective studies have shown that corticosteroids can be safely withdrawn from months to years after transplant. We prospectively investigated the effects of early immunosuppression without the use of corticosteroids on graft outcome and transplant complications.

METHODS

Forty-five patients undergoing liver transplantation were randomized to receive immunosuppression composed of cyclosporine microemulsion and azathioprine with (n=22) or without prednisone (n=23), in conventional doses. In those patients who received prednisone, this was withdrawn within 3 months after transplant. The median follow-up of survivors was 14 months (range: 6-24). The study end points were to determine graft survival and function, infectious complications, including hepatitis C virus (HCV)-RNA levels in HCV-infected recipients, acute rejection, kidney function, and metabolic complications.

RESULTS

Eleven deaths occurred, 6 of which were in the prednisone group. Two-year survival did not differ between patients treated with or without prednisone (70.2% vs. 78.3%, P=0.83), nor did the causes of death. No differences were observed with regard to graft function, renal function, and infectious complications. In the subset of patients who received transplants for HCV-related cirrhosis, the dynamics of virus replication HCV-RNA was faster among those treated with prednisone. The incidence and severity of acute rejection was similar in the two groups. More than 80% of acute rejections in both groups were classified as mild or moderate and underwent spontaneous resolution. Only two patients in each group had severe acute rejection requiring additional treatment with high-dose steroids. Patients receiving prednisone tended to have greater biochemical signs of cholestasis, higher serum cholesterol and glucose levels, and more frequent insulin requirement than those treated without corticosteroids.

CONCLUSIONS

Liver transplantation can be performed safely without using corticosteroids in the early postoperative course, and there is no need for routine aggressive steroid treatment of established acute rejections.

Further observations on the presence of ganglion cells in the oculomotor nerves of mammals and fish: number, origin and probable functions

The oculomotor nerves (3rd, 4th and 6th) of some species of fish and mammals have been studied to establish the presence, number, true topography and probable functional role of the ganglion cells located along the trunk. The finding of typical pseudo-unipolar ganglion cells is always unpredictable and extremely variable, from an inter- and intra-specific point of view, in members of the two zoological classes studied.

Association of polo-like kinase with alpha-, beta- and gamma-tubulins in a stable complex

The polo-like kinase (Plk) family has been shown to have an important role in the regulation of the cell-division cycle, especially in organization of the spindle structure, in species from fungi to humans. Recent reports have demonstrated that in mammalian cells Plk is associated with components of the anaphase-promoting complex and a peptidyl-prolyl isomerase, Pin1. To characterize a putative Plk-containing complex, we fractionated mitotic cell lysates on a gel-filtration column. The Plk complex was eluted from the column at molecular sizes ranging from 669 to 2500 kDa in the presence of detergent and high concentrations of salt. Specific associations of Plk with alpha-, beta- and gamma-tubulins in both interphase and mitotic cells were shown by reciprocal immunoprecipitations and immunoblottings and were independent of the microtubule polymerization state, whereas binding assays in vitro indicated that Plk interacts with alpha- and beta-tubulins directly. In addition, mitotic Plk was able to phosphorylate associated tubulins in vitro. Finally, we show that the kinase domain of the Plk molecule is both required and sufficient for its binding to tubulins in vivo. The specific interaction between Plk and tubulins might provide a molecular basis for the physiological functions of Plk in regulating the cell cycle, particularly in establishing the normal bipolar spindle.

Role for the Rac1 exchange factor Vav in the signaling pathways leading to NK cell cytotoxicity

Here we investigate the activation of and a possible role for the hematopoietic Rac1 exchange factor, Vav, in the signaling mechanisms leading to NK cell-mediated cytotoxicity. Our data show that direct contact of NK cells with a panel of sensitive tumor targets leads to a rapid and transient tyrosine phosphorylation of Vav and to its association with tyrosine-phosphorylated Syk. Vav tyrosine phosphorylation is also observed following the activation of NK cells through the low-affinity Fc receptor for IgG (Fc gamma RIII). In addition, we demonstrate that both direct and Ab-mediated NK cell binding to target cells result in the activation of nucleotide exchange on endogenous Rac1. Furthermore, Vav antisense oligodeoxynucleotide treatment leads to an impairment of NK cytotoxicity, with Fc gamma RIII-mediated killing being more sensitive to the abrogation of Vav expression. These results provide new insight into the signaling pathways leading to cytotoxic effector function and define a role for Vav in the activation of NK cell-mediated killing.

3-year treatment with recombinant interferon-alpha as adjuvant therapy of cutaneous malignant melanoma

Interferon alpha (IFN alpha) has been demonstrated to possess a significant biological activity for cutaneous malignant melanoma (CMM). Although multiple adjuvant trials utilizing IFNá have been tested, no consensus on the optimal dosing schedule has been reached. From February 1993 to October 1997 we enrolled 86 CMM patients using low doses of IFN alpha-2b (3 MU/d TIW SC for 3 years) in a phase II study. Our present data show a median disease-free survival (DFS) of 30 months (range 2-62), comparable to those obtained in high-dose IFN alpha trials. These findings suggest that positive results may be also obtained using low doses of IFN alpha in adjuvant treatment of CMM patients. in contrast to the high dose, the low dose regimen was well tolerated with an acceptable quality of life of patients.

Beta 1 integrin cross-linking inhibits CD16-induced phospholipase D and secretory phospholipase A2 activity and granule exocytosis in human NK cells: role of phospholipase D in CD16-triggered degranulation

Recent data indicate that integrin-generated signals can modulate different receptor-stimulated cell functions in both a positive (costimulation) and a negative (inhibition) fashion. Here we investigated the ability of beta 1 integrins, namely alpha 4 beta 1 and alpha 5 beta 1 fibronectin receptors, to modulate CD16-triggered phospholipase activation in human NK cells. beta 1 integrin simultaneous cross-linking selectively inhibited CD16-induced phospholipase D (PLD) activation, without affecting either phosphatidylinositol-phospholipase C or cytosolic phospholipase A2 (PLA2) enzymatic activity. CD16-induced secretory PLA2 (sPLA2) protein release as well as its enzymatic activity in both cell-associated and soluble forms were also found to be inhibited upon beta 1 integrin coengagement. The similar effects exerted by specific PLD pharmacological inhibitors (2,3-diphosphoglycerate, ethanol) suggest that in our experimental system, sPLA2 secretion and activation are under the control of a PLD-dependent pathway. By using pharmacological inhibitors (2,3-diphosphoglycerate, wortmannin, ethanol) we also demonstrated that PLD activation is an important step in the CD16-triggered signaling cascade that leads to NK cytotoxic granule exocytosis. Consistent with these findings, fibronectin receptor engagement, by either mAbs or natural ligands, resulted in a selective inhibition of CD16-triggered, but not of PMA/ionomycin-induced, degranulation that was reversed by the exogenous addition of purified PLD from Streptomyces chromofuscus.

Effects of long-term administration of methotrexate on bone mineral density in rheumatoid arthritis

Because previous studies of high-dose methotrexate usage have demonstrated an effect on bone formation and resorption, this study was done to determine whether long-term, low-dose use of methotrexate for the treatment of rheumatoid arthritis causes bone loss. Bone mineral density (BMD) of the lumbar spine and hip was measured in 10 Caucasian postmenopausal women who had never received methotrexate and 10 Caucasian postmenopausal women who had received the drug for 3 or more years. There were no significant differences in BMD at the lumbar spine (L2-L4) between patients who had used long-term methotrexate compared with patients never treated with methotrexate (1.08 +/- 0.08 g/cm2 versus 0.98 +/- 0.14 g/cm2, respectively; P = 0.08). Similarly, there were no significant differences in BMD at the femoral neck between methotrexate users and nonusers (0.81 +/- 0.08 g/cm2 versus 0.76 +/- 0.15 g/cm2, respectively; P = 0.42). These results suggest that long-term low-dose methotrexate treatment for rheumatoid arthritis is not associated with accelerated bone loss.

Polymerase chain reaction-based detection of circulating melanoma cells as an effective marker of tumor progression. Melanoma Cooperative Group

PURPOSE

Reverse transcriptase (RT) polymerase chain reaction (PCR) with multiple markers has been demonstrated to be highly sensitive in detecting circulating cells from patients with malignant melanoma (MM). We evaluated the clinical significance of the presence in peripheral blood of specific PCR-positive mRNA markers as an expression of circulating melanoma cells.

PATIENTS AND METHODS

Total cellular RNA was obtained from the peripheral blood of 235 patients with either localized (n = 154) or metastatic (n = 81) melanoma. We performed RT-PCR using tyrosinase, p97, MUC18, and MelanA/MART1 as gene markers. The PCR products were analyzed by gel electrophoresis and Southern blot hybridization. In addition, 20 healthy subjects and 21 patients with nonmelanoma cancer were used as negative controls.

RESULTS

Although detected at various levels among assessable patients, each mRNA marker was significantly correlated with disease stage. A significant correlation with disease stage was demonstrated for patients who were positive to all four markers (P < .0001) or to at least three markers (P < .001). Univariate analysis showed a significant correlation between risk of recurrence (evaluated in stage I, II, and III patients) and increasing number of PCR-positive markers (P = .0002). Logistic regression multivariate analysis indicated that each single marker (except tyrosinase) and, more especially, the presence of four PCR-positive markers remained statistically independent prognostic factors for tumor progression.

CONCLUSION

Our data establish the existence of a significant correlation among clinical stages, tumor progression, and presence of circulating melanoma-associated antigens in peripheral blood of MM patients. Preliminary assessment of a subset of patients with a higher risk of recurrence needs longer follow-up and further studies to define the role of RT-PCR in monitoring MM patients.

Epiluminescence microscopy as a useful approach in the early diagnosis of cutaneous malignant melanoma

The aim of this study was to evaluate the role of epiluminescence microscopy (ELM) in the differential diagnosis of cutaneous pigmented lesions in order to improve the detection of cutaneous malignant melanoma (CMM) at earlier stages of the disease. In total, 3865 pigmented lesions from 2121 selected patients were evaluated using ELM with a hand-held video microscope imaging system (MS 500B Micro-Scopeman, Moritex). Comparison with histology was performed on the 476 surgically excised lesions. ELM sensitivity, specificity, positive and negative predictive values as well as agreement for the different risk levels of the lesions were determined. Of the 476 cutaneous pigmented lesions removed and histologically examined, 101 (21.2%) were non-melanocytic lesions and 375 (78.8%) were melanocytic lesions. Overall agreement was 83.4% (93.1% and 80.8% for non-melanocytic and melanocytic lesions, respectively). Sensitivity and specificity of ELM in the analysis of melanocytic lesions with a pigment network were both very high (92.3% and 91.2%, respectively). Sixty new cases of CMM were identified. A high proportion of melanoma at stage AJCC IA (23 out of 32; 71.8%) was diagnosed exclusively by ELM (four of these were in situ CCM lesions). ELM is therefore a powerful tool to discriminate between melanocytic and non-melanocytic lesions in order to avoid inopportune surgical treatments for low risk lesions. Unfortunately, ELM did not show 100% sensitivity in diagnosing CMM and therefore ELM features should be integrated with data from both the history and clinical evaluation. However, ELM is much more accurate than clinical examination in detecting thin CMM.

Hepatic steatosis: a specific sign of hepatitis C reinfection after liver transplantation

Hepatitis C virus (HCV) infection is one of the major causes leading to orthotopic liver transplantation (OLT) worldwide. Although viral infection persists in almost all patients, the pathology of recurrent HCV infection after OLT is not well characterized. To address this issue, we compared the pathological findings of 28 patients who underwent transplantation for HCV-related cirrhosis (group A, aged 47 +/- 15 years; 23 men, 5 women) with those of 21 patients who underwent transplantation for nonviral indications (group B, aged 45 +/- 21 years; 13 men, 8 women) during the first year after transplantation. Patients from group A were assessed for serum HCV RNA by 5' untranslated region nested polymerase chain reaction before and 1 year after OLT. Patients underwent protocol liver biopsies 3 months and 1 year after transplantation. Group A patients more frequently had histological evidence of hepatic steatosis than group B patients, both at 3 months (P = .003) and 1 year (P = .003) after OLT. Fibrosis and portal inflammation were statistically more frequent in group A 1 year after transplantation. The sensitivity of steatosis in detecting histological disease recurrence was 100% at 3 months and 94% at 1 year; the specificity was 40% and 60%, respectively. Conversely, steatosis was 100% specific in detecting viral recurrence, with a sensitivity of 89%. The 1-year actuarial incidence of abnormal transaminase levels was 52% in group A and 13% in group B (P = .05). No biochemical or histological differences between patients infected with genotype 1b and patients with other HCV genotypes were found. Hepatic steatosis is a specific sign of viral recurrence after liver transplantation and a less specific sign of disease recurrence. HCV-infected liver transplant recipients often develop abnormal transaminase levels and liver fibrosis 1 year after OLT; these features are unrelated to HCV genotypes.

Integrin-mediated ras-extracellular regulated kinase (ERK) signaling regulates interferon gamma production in human natural killer cells

Recent evidence indicates that integrin engagement results in the activation of biochemical signaling events important for regulating different cell functions, such as migration, adhesion, proliferation, differentiation, apoptosis, and specific gene expression. Here, we report that beta1 integrin ligation on human natural killer (NK) cells results in the activation of Ras/mitogen-activated protein kinase pathways. Formation of Shc-growth factor receptor-bound protein 2 (Grb2) and Shc-proline-rich tyrosine kinase 2-Grb2 complexes are the receptor-proximal events accompanying the beta1 integrin-mediated Ras activation. In addition, we demonstrate that ligation of beta1 integrins results in the stimulation of interferon gamma (IFN-gamma) production, which is under the control of extracellular signal-regulated kinase 2 activation. Overall, our data indicate that beta1 integrins, by delivering signals capable of triggering IFN-gamma production, may function as NK-activating receptors.

Engraftment of HLA-matched sibling hematopoietic stem cells after immunosuppressive conditioning regimen in patients with hematologic neoplasias

BACKGROUND AND OBJECTIVE

The main objective of this pilot study was to assess the possibility of achieving engraftment of HLA-matched sibling donor mobilized hematopoietic stem cells after immunosuppressive non-myeloablative therapy. The second objective was to verify whether high-dose therapy with autologous stem cells rescue followed by allografting conditioned by only an immunosuppressive regimen, can be combined in order to achieve the reduction of tumor burden after autografting and the control of residual disease with immune-mediated effects after allografting.

DESIGN AND METHODS

To enter the pilot study the patients had to fulfil the following criteria: advanced resistant disease, presence of an HLA matched sibling donor, no general contraindications to stem cell transplantation. Our data refers to 9 patients: Hodgkin's disease (n = 4), non-Hodgkin's lymphoma (n = 2), advanced chronic myelogenous leukemia (n = 2) (one patient with accelerated phase Ph-negative but p190 BCR-ABL gene positive by RT-PCR and one with Ph-positive blastic phase), refractory anemia with excess of blasts t(1;3) (p36;q21) (n = 1). All patients but one received the combined approach. At a median of 40 days (range 30-96), after high-dose therapy and autologous stem cell engraftment, the patients were treated with immunosuppressive therapy consisting of fludarabine and cyclophosphamide (Flu-Cy protocol) and then HLA matched donor mobilized stem cells were infused into the patients. GvHD prophylaxis consisted of cyclosporin and methotrexate.

RESULTS

To date, with a median observation period of 4 months (range, 2-10), complete chimerism (100% donor cells) has been achieved in 6 patients. Three patients did not achieve complete chimerism: one patient died of progressive Hodgkin's disease when he reached 55% of donor cells, another patient is now in increasing phase of donor cell engraftment and the last patient (blastic phase-CML) was the only case who appears to have had autologous recovery. Two of the Hodgkin's disease patients, who were in partial remission after autografting, achieved complete remission after allografting and both are disease free 2 and 6 months after. Another Hodgkin's disease patient is alive at 10 months but she has progressive disease. One of the two patients with non-Hodgkin's lymphoma, who achieved partial remission after autografting, obtained complete remission and he is disease free 2 months after allografting. The other patient maintains partial remission obtained after autografting. The accelerated phase-CML patient obtained hematologic and molecular remission; the RAEB patient achieved hematologic and cytogenetic remission. In two patients severe aGVHD (grade II-III) was the single major complication but neither patient died of it. Mild aGVHD was seen in another patient. In only one patient did the ANC decrease to below 1 x 10(9)/L and in no case did platelets decrease below 20 x 10(9)/L. No patients required a sterile room or any red cell or platelet transfusions.

INTERPRETATION AND CONCLUSIONS

Immunosuppressive therapy with a Flu-Cy protocol allowed engraftment of HLA-matched sibling donor stem cells without procedure-related deaths; moreover, we have demonstrated that this combined procedure can be pursued in safety in a serious ill population and some of these patients achieved a complete remission. This procedure is not likely to be curative, but a fascinating step along the path to curing these diseases. Of course, the follow-up is too short to document the incidence of cGvHD.

Immunosuppression without prednisone after liver transplantion is safe and associated with normal early graft function: preliminary results of a randomized study

Prednisone has been commonly considered the mainstay of immunosuppressive therapy after liver transplantation. Recent data suggest that prednisone withdrawal late after transplant reduces complications without affecting graft function. We report here the preliminary results of an open-label, randomized study aimed at investigating whether prednisone therapy can be completely avoided during the first 3 months after transplantation. Twenty-seven consecutive patients were randomized to receive double (group A: cyclosporine and azathioprine) or triple (group B: prednisone, cyclosporine, and azathioprine) immunosuppressive therapy after liver transplantation. Six patients died within the first 3 weeks in each group and were excluded from the calculations. The present results refer to 10 patients in group A and 11 in group B. The actuarial 1-year survival did not differ between the two groups (90.9% vs 88.8%). There were no differences with respect to infectious complications or episodes of histological acute graft rejections. Only one severe acute rejection occurred in group A and two in group B. During the first month after transplant, liver and kidney functions tended to be better in the group of patients treated without prednisone, although there were no differences in the mean cyclosporine blood levels. These data, though preliminary, indicate that early immunosuppression without the use of prednisone is safe and tends to be associated with improved liver and renal functions compared to conventional triple therapy.

Tailored therapy for aggressive non-Hodgkin's lymphoma: results of a phase II study with a long-term follow-up

Aim of the study was to improve cure rate and survival of aggressive non-Hodgkin's lymphoma (NHL) with a tailored program of therapy based on histologic type, prognostic characteristics of patients and response to therapy, and with the use of differentiating or cytostatic agents such as Ara-C at low doses and alphaIFN. Fifty-four consecutive patients with aggressive NHL were treated in the induction phase with 4 sequential courses of a third generation regimen (modified CODBLAM IV), followed in responsive patients by 1 cycle of doxorubicin and cyclophosphamide and 1 cycle of high dose methotrexate with folinic acid rescue (AC-MTX). Patients who achieved partial response (PR) were treated with the combination of CCNU + vinblastine if affected by high grade NHL, or with low dose Ara-C plus alphaIFN if affected by intermediate grade NHL. Patients who obtained complete response (CR) with basal adverse prognostic factors were treated with alphaIFN as maintenance therapy for two years. Radiotherapy and surgery were effected in selected cases. Thirty-four patients (62.9%) achieved CR and 12 patients (22.2%) showed PR after induction therapy. Among the 12 patients who achieved PR, 6 prolonged CRs were obtained in 7 patients treated with Ara-C at low doses plus alphaIFN and 4 CRs were obtained in 5 patients treated with CCNU + vinblastine. After completion of treatment, 44 patients (81.5%) obtained CR, 2 patients (3.7%) showed PR and 8 patients (14.8%) presented progression of disease (PD). Fifteen patients received alphaIFN as maintenance therapy. The overall survival and failure-free survival rates are 53.7% and 50% respectively, with a median follow-up of 82 months: 27 patients remain alive, disease-free without relapses, and can be considered cured. This tailored program of therapy resulted effective and moderately toxic and may improve the outcome in aggressive NHL.

5-Fluorouracil plus interferon alpha-2a compared to 5-fluorouracil alone in the treatment of advanced colon carcinoma: a multicentric randomized study

Biochemical modulation is one of the most interesting fields in cancer chemotherapy. Interferon-alpha (IFNalpha) is a cytokine that is able to influence the pharmacodynamics of 5-fluorouracil (5FU) through a number of mechanisms. With the aim of confirming some data emerging from the literature, we initiated a multicentric randomized study comparing the combination of 5FU and IFNalpha-2a with 5FU alone in the treatment of advanced or metastatic colon cancer. A group of 205 colon cancer patients (104 in the 5FU arm and 101 in the 5FU + IFNapha-2a arm) were included in the final intention-to-treat analysis. Rectal cancers were not considered eligible. All patients had measurable disease, were aged 75 years or less, had a Karnofsky index of at least 60 and had good bone marrow, renal, liver and cardiac functions. No previous chemo-immunotherapy was allowed. The treatment was 750 mg/m2 5FU (4 h i.v. infusion) on days 1 5 and then i.v. bolus weekly, starting from day 12, with or without IFNalpha-2a given s.c. three times weekly (starting dose 3 x 10(6) IU rising to 9 x 10(6) IU, if tolerated). Patients were treated until progression or, if responsive, for a maximum of 48 weeks and then observed for a period of 2 years. The primary end-point of the study was objective clinical response (OR); secondary parameters were time to progression, overall survival, and time to death after progression. WHO criteria were used for both clinical response and toxicity measurements. Dose reduction was planned a priori in the event of significant toxicity due to 5FU, IFNalpha-2a or both. Association between primary and secondary end-points and treatment was studied by univariate and multivariate analysis. Altogether, 47 patients achieved a documented response. A 25% OR was observed in the combination arm while a 21% OR was seen in the 5FU arm; this difference is not statistically significant (P = 0.6). Patients with a small tumour burden (below 5 cm2) showed a higher probability of response in both arms. Patients in the experimental arm had a higher but not statistically significant cumulative progression-free probability. Median survival was 47.1 weeks overall, while it was 43.7 and 48.5 weeks in the control and experimental arms, respectively. The combination was clearly more toxic than 5FU alone, leukopenia being the most frequent side-effect in the experimental arm and nausea and vomiting in the control arm. In conclusion these results are quite disappointing and 5FU + IFNalpha-2a can not be considered a standard treatment for advanced colon cancer.

Specific engagement of the CD94/NKG2-A killer inhibitory receptor by the HLA-E class Ib molecule induces SHP-1 phosphatase recruitment to tyrosine-phosphorylated NKG2-A: evidence for receptor function in heterologous transfectants

It has been recently demonstrated that the CD94/NKG2-A killer inhibitory receptor (KIR) specifically recognizes the HLA-E class Ib molecule. Moreover, the apparent CD94-mediated specific recognition of different HLA class Ia allotypes, transfected into the HLA-defective cell line 721.221, indeed depends on their selective ability to concomitantly stabilize the surface expression of endogenous HLA-E molecules, which confer protection against CD94/NKG2-A+ effector cells. In the present study, we show that a selective engagement of the CD94/NKG2-A inhibitory receptor with a specific monoclonal antibody (mAb) (Z199) was sufficient to induce tyrosine phosphorylation of the NKG2-A subunit and SHP-1 recruitment. These early biochemical events, commonly related to negative signaling pathways, were also detected upon the specific interaction of NK cells with an HLA-E+ 721.221 transfectant (.221-AEH), and were prevented by pre-incubation of .221-AEH with an anti-HLA class I mAb. Furthermore, mAb cross-linking of the CD94/NKG2-A receptor, segregated from other NK-associated molecules by transfection into a rat basophilic leukemia cell line (RBL-2H3), promoted tyrosine phosphorylation of NKG2-A and co-precipitation of SHP-1, together with an inhibition of secretory events triggered via Fc epsilonRI. Remarkably, interaction of CD94/NKG2-A+ RBL cells with the HLA-E+ .221-AEH transfectant specifically induced a detectable association of SHP-1 with NKG2-A, constituting a more formal evidence for the receptor-HLA class I interaction.

In vivo detection of malignant thymic masses by indium-111-DTPA-D-Phe1-octreotide scintigraphy

Many tumors with neuroendocrine characteristics express high amounts of somatostatin receptors that enable in vivo imaging with [(111)In-DTPA-D-Phe1]-octreotide. In this study, we have analyzed the feasibility in detecting and characterizing thymic masses by somatostatin receptor scintigraphy (SRS).

METHODS

Eighteen patients (13 women, 5 men, ages 18-78 yr; mean +/- s.d. = 42.1 +/- 17.6 yr) were enrolled in this study. Eleven patients were studied during diagnosis and seven during routine follow-up. In seven patients, myasthenia gravis was the presenting symptom. SRS was performed within 4 wk after CT and/or MRI. Planar and tomographic images were acquired within 24 hr after the injection of approximately 111 MBq of [(111)In-DTPA-D-Phe1]-octreotide. The scintigraphic results were categorized according to the histologic findings.

RESULTS

Histology diagnosed 10 mixed epithelial/lymphoid thymomas (8 with prevalent epithelial component), 2 thymic carcinomas, 1 thymic carcinoid, 1 lymphangioma and 4 thymic hyperplasias. Two thymoma were Stage I, 3 were Stage II, 2 were Stage III and 5 were Stage IV, as was the thymic carcinoid. Indium-111-DTPA-D-Phe1-octreotide concentrated in primary and/or metastatic sites of thymic tumors, thereby enabling successful external gamma imaging of sites greater than 1.5 cm in size. Tumor-to-lung (T/L) ratios were as high as 7.6-fold (range 1.7-7.6). Untreated thymomas showed higher T/L (4.34 +/- 1.57) than treated ones (2.68 +/- 1.18). No uptake was detectable in the four patients with benign thymic hyperplasia and the patient with the lymphangioma.

CONCLUSION

Indium-111-DTPA-D-Phe1-octreotide is avidly concentrated within thymic tumors, but it is not concentrated by thymic hyperplasia, which allows differential diagnosis. Thus, in patients with myasthenia gravis, SRS may have a role in characterizing thymic masses, thereby overcoming the limits of cross-sectional imaging modalities.

Cardiac rhabdomyosarcoma: a clinicopathologic and electron microscopy study

A 66-year-old woman was admitted to the hospital with a neurological syndrome characterized by ataxia and diplopia. Magnetic resonance of the brain documented an ischemic medullary lesion. Examination of the heart revealed a grade 2/6 systolic murmur at the left sternal border and apex that radiated towards the axilla. The echocardiography study showed a mild mitral regurgitation, and an abnormally enlarged posterior papillary muscle was found in the left ventricle. Two weeks after admission, the patient died suddenly due to a stroke. At autopsy, a recent vast swollen ischemic cerebral infraction was found. Furthermore, two old infarcts were observed in the spleen. A cardiac examination showed a white-gray ulcered mass in the left ventricle and histological analysis revealed a rhabdomyosarcoma.

CD16-mediated activation of phosphatidylinositol-3 kinase (PI-3K) in human NK cells involves tyrosine phosphorylation of Cbl and its association with Grb2, Shc, pp36 and p85 PI-3K subunit

Phosphatidylinositol 3-kinase (Pl-3K) plays a key role in several cellular processes, including mitogenesis, apoptosis, actin reorganization and vesicular trafficking. The molecular events involved in its activation have not been fully elucidated and several reports indicate that a key event for enzyme activation is the interaction of the SH2 domains of the p85 regulatory subunit of Pl-3K with tyrosine-phosphorylated proteins. In this study, we investigated the involvement of the product of the proto-oncogene c-Cbl in the activation of Pl-3K triggered by CD16 in human NK cells and the possible mechanisms leading to Pl-3K recruitment to the plasma membrane. Our results indicate that stimulation of NK cells through CD16 results in a rapid tyrosine phosphorylation of Cbl, which is constitutively associated with Grb2 and forms an activation-dependent complex with the p85 subunit of Pl-3K. In addition, we detected the presence of the Grb2-associated tyrosine-phosphorylated p36 and Shc proteins in anti-Cbl and anti-p85 immunoprecipitates from CD16-stimulated NK cell lysates. Upon CD16 stimulation, Pl-3K activity was found associated with Cbl and to a lesser extent with Grb2 and Shc as well as with the zeta chain of the CD16 receptor complex. Overall these results suggest that the formation of a complex containing either Shc or pp36 associated with Grb2, Cbl and the p85 subunit of Pl-3K is one of the major mechanisms which might couple CD16 to the Pl-3K pathway in NK cells.