ALK gene copy number gains in non-small-cell lung cancer: prognostic impact and clinico-pathological correlations.

BACKGROUND: The correlation between ALK gene copy number gain (ALK-CNG) and prognosis in the context of advanced non-small-cell lung cancer (NSCLC) remains a controversial issue. This study aimed to evaluate the association among ALK-CNG according to Fluorescent In Situ Hybridization (FISH), clinical characteristics and survival in resectable and advanced NSCLC. METHODS: Clinical and pathological data of patients with resectable and advanced NSCLC were retrospectively collected. Tumor tissues were analyzed for ALK-CNG by FISH, and patients were divided in 3 groups/patterns on the basis of ALK signals: disomic [Pattern A], 3-7 signals [Pattern B], >7 signals [Pattern C]. The association between clinical and pathological features and ALK-CNG patterns was evaluated. Disease/progression-free and overall survival (DFS/PFS and OS) were estimated using the Kaplan-Meyer method. RESULTS: A number of 128 (76.6 %) out of the 167 eligible patients were evaluable for ALK-CNG, displaying pattern A, B and C in 71 (42.5 %), 42 (25.1 %) and 15 (9 %) patients, respectively. Gains in ALK-CNG appear to be more frequent in smokers/former smokers than in non-smokers (74.2 % versus 20.4 %, respectively, p = 0.03). Pattern A and C seem more frequently associated with higher T-stage (T3-4), while pattern B appears more represented in lower T-stage (T 1-2) (p = 0.06). No significant differences in survival rate were observed among the above groups. CONCLUSIONS: A high ALK-CNG pattern might be associated with smoking status and theoretically it might mirror genomic instability. The implications for prognosis should be prospectively investigated and validated in larger patients' series. TRIAL REGISTRATION: We confirm that all the study was performed in accordance with relevant guidelines and regulations and that all the protocol (part of a larger project MFAG 2013 N.14282) was approved by the local Ethics Committee of the Azienda Ospedaliera Universitaria Integrata of Verona on November 11st, 2014.

Epithelial-to-mesenchymal transition (EMT) induced by inflammatory priming elicits mesenchymal stromal cell-like immune-modulatory properties in cancer cells.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) has a central role in cancer progression and metastatic dissemination and may be induced by local inflammation. We asked whether the inflammation-induced acquisition of mesenchymal phenotype by neoplastic epithelial cells is associated with the onset of mesenchymal stromal cell-like immune-regulatory properties that may enhance tumour immune escape. METHODS: Cell lines of lung adenocarcinoma (A549), breast cancer (MCF7) and hepatocellular carcinoma (HepG2) were co-cultured with T, B and NK cells before and after EMT induction by either the supernatant of mixed-lymphocyte reactions or inflammatory cytokines. RESULTS: EMT occurrence following inflammatory priming elicited multiple immune-regulatory effects in cancer cells resulting in NK and T-cell apoptosis, inhibition of lymphocyte proliferation and stimulation of regulatory T and B cells. Indoleamine 2,3-dioxygenase, but not Fas ligand pathway, was involved at least in part in these effects, as shown by the use of specific inhibitors. CONCLUSIONS: EMT induced by inflammatory stimuli confers to cancer cells some mesenchymal stromal cell-like immune-modulatory properties, which could be a cue for cancer progression and metastatic dissemination by favouring immune escape.

Heterogeneous distribution of mechanical stress in human lung: a mathematical approach to evaluate abnormal remodeling in IPF.

Idiopathic pulmonary fibrosis (IPF) is the most common and severe form of idiopathic interstitial pneumonia. A recently proposed pathogenic model suggests that the concurrent action of cell senescence, exposure to cigarette smoke and mechanical stress due to respiratory lung movements lead to a localized exhaustion of tissue renewal capacity with eventual alveolar loss and abnormal lung remodeling. In this study we have compared the distribution of IPF lesions, as shown by TC radiological images, with the hypothetical distribution of maximal mechanical stress obtained by a simplified mathematical model. The geometry and distribution of stress as determined by our simulation are closely similar to those demonstrated in vivo in the lungs of patients with idiopathic pulmonary fibrosis using high resolution CT scan radiological imaging. These data argue in favor of the recently proposed contribution of mechanical stress to progressive damage and remodeling of lung parenchyma in IPF. The parameters of the model can be tuned on the age of the patients.

Idiopathic nonspecific interstitial pneumonia: an interstitial lung disease associated with autoimmune disorders?

Recent evidence suggests that idiopathic nonspecific interstitial pneumonia (iNSIP) is a distinct clinical entity amongst other idiopathic interstitial pneumonias, and some data seem to suggest a possible pathogenetic role of autoimmunity. The aim of the present study was to assess if iNSIP might represent an early lung manifestation of an autoimmune disease. After initial review of cases found in the medical records database by searching for the term "NSIP" (n = 63), 37 iNSIP cases were identified, and were re-evaluated using a dynamic integrated multidisciplinary approach. 27 cases with iNSIP were selected for the study. Mean ± sd age at first respiratory symptom was 54.2 ± 8 yrs, 70% were females, and 59% were never-smokers. At follow-up (mean ± sd 59.7 ± 29 months, range 12-138 months), autoimmune diseases occurred in 14 (52%) patients, with seven (26%) cases of autoimmune thyroiditis, six (22%) of undifferentiated connective tissue disease and three (11%) of connective tissue disease. Patients developing autoimmune diseases were older and more frequently never-smoking females. In >50% of patients diagnosed with iNSIP, evidence of autoimmune diseases develops within 2 yrs, suggesting a probable link between the clinical entity of iNSIP and autoimmune disorders.

Prospective evaluation of drug-induced lung toxicity with high-resolution CT and transbronchial biopsy.

PURPOSE: This study compared the results of high-resolution computed tomography (HRCT) and cytohistology after transbronchial biopsy in the evaluation of drug-related interstitial lung disease (DR-ILD). MATERIALS AND METHODS: Patients with a clinical and imaging diagnosis of DR-ILD were prospectively included in a study protocol lasting 5 years. All patients were evaluated by bronchoscopy with transbronchial biopsy or bronchoalveolar lavage (BAL) following an HRCT examination that raised a suspicion of DR-ILD. Two radiologists (one senior and one junior), unaware of the diagnosis, reported the single HRCT findings, their distribution and predominant pattern. In the event of disagreement, the diagnosis was subsequently reached by consensus. Cytohistological examination was considered the gold standard in the diagnosis of DR-ILD. Patients who were unable to undergo the endoscopic procedure were excluded from the study. RESULTS: The study included 42 patients (25 men, 17 women; age range 20-84 years). Transbronchial biopsy was performed in all but four patients (one case of alveolar haemorrhage and three cases of lipoid pneumonia) in whom the diagnosis was established with BAL. Assessment of the HRCT images revealed the following patterns: noncardiogenic pulmonary oedema (n=13); organising pneumonia (OP) (n=9); hypersensitivity pneumonitis (HP) (n=2); alveolar haemorrhage (AH) (n=2); nonspecific interstitial pneumonia (NSIP) (n=5); lipoid pneumonia (LP) (n=1); sarcoid-like pattern (n=1). Cytohistological diagnosis revealed diffuse alveolar damage (DAD) in 11 patients, OP in seven, HP in three, AH in three, chronic interstitial pneumonia (CIP) in eight, LP in three and pseudosarcoidosis in one. Subdivision of the drugs into antineoplastic and nonantineoplastic agents showed that the most common patterns were CIP (n=6), DAD (n=2) and OP (n=2) in the antineoplastic group and DAD (n=9) and OP (n=5) in the nonantineoplastic group. Sensitivity and specificity of the radiological analysis was excellent, especially for patterns such as OP and DAD (sensitivity 0.86 and specificity 0.88 for OP; sensitivity 1 and specificity 0.93 for DAD). CONCLUSIONS: HRCT demonstrated excellent sensitivity and specificity. In cases in which its specificity was low, HRCT was nonetheless useful for biopsy planning and clinical-radiological monitoring after discontinuation of the drug treatment.

Role of human tissue kallikrein in gastrointestinal stromal tumour invasion.

BACKGROUND: Human tissue kallikrein (hK1) generates vasodilator kinins from kininogen and promotes angiogenesis by kinin-dependent and kinin-independent mechanisms. Here, we investigate the expression and functional relevance of hK1 in human gastrointestinal stromal tumour (GIST). METHODS: Vascularisation and hK1 expression of GIST samples were assessed by immunohistochemistry. In two GIST cell lines, hK1 expression was assessed by PCR, and hK1 protein levels and activity were measured by ELISA and an amidolytic assay, respectively. The effect of hK1 silencing, inhibition or overexpression on GIST cell proliferation, migration and paracrine induction of angiogenesis was studied. Finally, local and systemic levels of hK1 were assessed in mice injected with GIST cells. RESULTS: Human tissue kallikrein was detected in 19 out of 22 human GIST samples. Moreover, GIST cells express and secrete active hK1. Titration of hK1 demonstrated its involvement in GIST invasive behaviour, but not proliferation. Furthermore, hK1 released by GIST cells promoted endothelial cell migration and network formation through kinin-dependent mechanisms. Gastrointestinal stromal tumour implantation in nude mice resulted in local and systemic hK1 expression proportional to tumour dimension. CONCLUSIONS: Human tissue kallikrein is produced and released by GIST and participates in tumour invasion. Further studies are needed to validate hK1 as a diagnostic biomarker and therapeutic target in GIST.

Epithelial stem cell exhaustion in the pathogenesis of idiopathic pulmonary fibrosis.

New paradigms have been recently proposed in the pathogenesis of idiopathic pulmonary fibrosis (IPF), evidencing that in IPF the cumulative action of an accelerated parenchymal senescence determined by either telomere dysfunction or genetic defects, together with the concurrent noxious activity of tobacco smoking, are able to severely compromise the regenerative potential of parenchymal epithelial stem cells, triggering a cascade of molecular signals and events (scarring, bronchiolar proliferation, abnormal remodelling) eventually leading to severe and irreversible functional impairment. New pathogenic schemes focus on the complex molecular mechanisms driving in a vicious circle the different signalling pathways (e.g. Wnt/ -catenin, TGF-beta, caveolin-1, etc.) potentially involved in epithelial-mesenchymal transition and irreversible lung remodelling.

Cathepsin-K immunoreactivity distinguishes MiTF/TFE family renal translocation carcinomas from other renal carcinomas.

The microphthalmia transcription factor/transcription factor E (TFE)-family translocation renal cell carcinomas bear specific translocations that result in overexpression of TFE3 or TFEB. TFE3 fusion gene product overexpression occurs as consequence of different translocations involving chromosome Xp11.2, whereas TFEB overexpression is the result of the specific translocation t(6;11)(p21;q12), which fuses the Alpha gene to TFEB. Both TFE3 and TFEB are closely related members of the microphthalmia transcription factor/TFE-family, which also includes TFEC and microphthalmia transcription factor. These transcription factors have overlapping transcriptional targets. Overexpression of microphthalmia transcription factor has been shown to mediate the expression of cathepsin-K in osteoclasts. We hypothesize that the overexpression of the related TFE3 fusion proteins and TFEB in translocation renal cell carcinomas may have the same effect. We studied cathepsin-K in 17 cytogenetically confirmed microphthalmia transcription factor/TFE-family translocation renal cell carcinomas. Seven cases showed a t(6;11)(p21;q12), ten cases showed translocations involving Xp11.2; five cases t(X;1)(p11;q21) resulting in a PRCC-TFE3 gene fusion; three cases t(X;1)(p11;p34) resulting in a PSF-TFE3 gene fusion, one t(X;17)(p11;q25) resulting in an ASPL-TFE3 gene fusion, and one t(X;3)(p11;q23) with an unknown TFE3 gene fusion. As control we analyzed cathepsin-K in 210 clear cell, 40 papillary, 25 chromophobe renal cell carcinomas and 30 oncocytomas. All seven TFEB translocation renal cell carcinomas were labeled for cathepsin-K. Among the cytogenetically confirmed TFE3 translocation renal cell carcinomas, 6 out of 10 were positive. None of the other renal neoplasms expressed cathepsin-K. We conclude the following: (1) cathepsin-K is consistently and strongly expressed in TFEB translocation renal cell carcinomas and in 6 of 10 TFE3 translocation renal cell carcinomas. (2) Cathepsin-K immunolabeling in both TFE3 and TFEB translocation renal cell carcinomas distinguishes these neoplasms from the more common adult renal cell carcinomas, and may be a specific marker of these neoplasms. (3) These results further support the concept that the overexpression of TFE3 or TFEB in these neoplasms activates the expression of genes normally regulated by microphthalmia transcription factor in other cell types.

The role of transbronchial lung biopsy for the diagnosis of diffuse drug-induced lung disease: a case series of 44 patients.

At present, no studies have evaluated the role of bronchoscopic transbronchial lung biopsy (TBLB) in the diagnosis of diffuse drug-induced lung disease (DILD), and there is no consensus for a definite diagnostic workup approach for this rare clinical entity. The aim of the present study was to evaluate the clinical usefulness of TBLB in diffuse DILD. This study was a retrospective analysis of patients with diffuse DILD, who underwent bronchoscopy. The role of TBLB was assessed to determine whether the histological results are useful for the final diagnosis. Over a 5-yr period, 44 patients underwent bronchoscopy, and all had a bronchoalveolar lavage (BAL). Thirty-three of the 44 patients underwent TBLB (75%), and the results of TBLB were diagnostically helpful in 25 (75.7%) of the procedures. No histopathologic abnormality was identified in 6 (18%) of the 33 patients. In 2 patients (6%) the obtained samples were not adequate, since no lung parenchyma was obtained. No severe complications related to bronchoscopic procedures occurred. In conclusion, TBLB is a safe procedure, and is diagnostically helpful in the majority of cases of patients with diffuse DILD. Histological data obtained by TBLB further corroborate clinical, laboratory, radiologic and BAL results for a definitive diagnosis of diffuse DILD.

ZAP-70 expression, as detected by immunohistochemistry on bone marrow biopsies from early-phase CLL patients, is a strong adverse prognostic factor.

Zeta-associated protein-70 (ZAP-70), mostly assessed by flow-cytometry (FC), recently emerged as reliable prognostic factor in chronic lymphocytic leukaemia (CLL) at presentation. We evaluated ZAP-70 expression in 156 CLL patients by immunohistochemistry (IHC) on formalin-fixed bone marrow (BM) biopsies at diagnosis. At presentation, 117 patients (75%) were with Binet stage A, 27 (17%) stage B and 12 (8%) stage C. Median follow-up was 61 months (range 6-242). ZAP-70 was expressed in neoplastic lymphocytes of 69 patients (44%). Concordance between ZAP-70 by IHC and ZAP-70 by FC, immunoglobulin heavy chain variable genes (IGHV) mutational status and CD38 expression was found in 41/46 (89%), 41/49 (80%) and in 60/88 (68%) tested cases, respectively. ZAP-70 expression significantly correlated with advanced Binet stage (B-C), diffuse BM infiltration, increased lactate dehydrogenase (LDH) and beta2-microglobulin serum levels and lymphocyte doubling time <12 months. ZAP-70 positivity was significantly related to poorer time to progression (median 16 months vs 158 of ZAP-70-negative cases) (P<0.0001) and overall survival (median 106 months vs not reached) (P=0.0002); this correlation was confirmed at multivariate analysis. ZAP-70 expression correlated with poorer outcome also when evaluated only in the 117 stage A patients. In conclusion, immunohistological detection of ZAP-70 on formalin-fixed BM biopsies at diagnosis appears a useful methodological approach to identify patients with poor prognosis in CLL.

The value of transbronchial lung biopsy using jumbo forceps via rigid bronchoscope in diffuse lung disease.

BACKGROUND: Transbronchial lung biopsy (TBLB) is a valuable procedure used to obtain a parenchymal specimen in the evaluation of diffuse lung infiltrates. Large forceps are expected to result in larger specimens and improve diagnostic yield. AIM: The objective of this study was to evaluate diagnostic yield of TBLB using large modified flexible gastroenterological forceps ("Jumbo forceps") compared with 'normal' flexible forceps via rigid bronchoscopy in patients with diffuse parenchymal lung disease (DPLD). METHODS: The study was a prospective analysis of 95 patients who underwent fluoroscopy guided TBLB over a two year period. Patients with a lung mass or solitary lung nodule undergoing TBLB were excluded. The larger and small forceps were used in a random sequence to avoid a reduction in diagnostic yield of the second series of biopsies related to possible bleeding by first series of biopsies. To minimize the consequence of haemorrhage, we performed every rigid bronchoscopy, placing a non inflated Fogarty balloon and a rigid aspirator (diameter 4 mm) in lobar bronchus near the biopsy segment. The Fogarty balloon has been inflated in case of bleeding. After the bleeding was controlled we continued to operate up to the biopsy segment. RESULTS: Diagnostic yield of TBLB using Jumbo forceps was significantly higher than using normal flexible forceps via rigid bronchoscopy in patients with DPLD (p = 0.001). In 74 out of 95 patients (78%) the diagnosis was placed with Jumbo forcep while the smaller forcep was diagnostic in 62 out of 95 patients (65%). Large forceps obtained significantly more tissue than the small forceps; the biopsy specimen taken with normal forcep measured in average 1.4 x 1.0 mm and the larger biopsy taken with jumbo forcep measured in average 2.5 x 1.9 mm (p < 0.005). CONCLUSION: The use of large biopsy forceps to perform TBLB via rigid bronchoscope can significantly increase diagnostic yield in the pathological diagnosis of diffuse infiltrative lung disease.

Identification of malignant plasma cell precursors in the bone marrow of multiple myeloma.

Precursors of plasma cells were studied in the bone marrow of 28 patients with multiple myeloma, plasma cell leukemia, and benign monoclonal gammopathy. Pre-B and B cell populations were analyzed with anti-B monoclonal antibodies corresponding to the clusters standardized at the Leucocyte Typing Workshops in Paris and Boston (CD9, CD10, CD19-22, CD24). In advanced forms of plasma cell malignancies, such as cases of multiple myeloma in stages II and III and of plasma cell leukemia, some cells of lymphoid morphology expressed common acute lymphoblastic leukemia antigen (CALLA, CD10) and HLA-DR, but contained no detectable terminal deoxynucleotidyl transferase enzyme. These CALLA+ cells were absent in benign monoclonal gammopathies. In multiple myeloma, the CALLA+ cells were negative for surface and cytoplasmic immunoglobulins (Ig), and, unlike CALLA+, terminal deoxynucleotidyl transferase (TdT+) pre-B cells in the normal bone marrow also failed to react with antibodies to B cell-associated antigens such as CD9, CD19, CD22, and CD24. The CALLA+, Ig- cells could be regarded as preplasmacytic since, after having been separated and stimulated with the phorbol ester 12-0-tetradecanoyl-phorbol-13 acetate in vitro, they transformed into plasma cells and synthesized the same heavy and light chains as myeloma cells.

ZAP-70 is expressed by normal and malignant human B-cell subsets of different maturational stage.

ZAP-70 tyrosine kinase is involved in signalling pathways following T-cell receptor stimulation and was originally described only in T cells and natural killer cells. ZAP-70 expression has been reported in normal mouse B lineage cells and in human malignant B lymphocytes, mainly in chronic lymphocytic leukemia (CLL) where it correlates with clinical outcome. We analyzed several B-cell lines and ex vivo malignant B cells, ranging from acute lymphoblastic leukemia to multiple myeloma and reflecting different stages of B-cell differentiation, and they showed ZAP-70 expression regardless their maturation stage. We then analyzed by Western blot and flow cytometry different human normal B-lymphocyte subpopulations: naïve, germinal center and memory B cells from tonsils, CD19+ CD5+ cells from cord blood and CD19+ lymphocytes from peripheral blood. All expressed ZAP-70 protein, though at different levels depending on their differentiation, activation and tissue localization. In addition, ZAP-70 expression levels could be modulated following stimulation via the B-cell receptor. These findings implicate a potential role of ZAP-70 in the signalling pathway of B lymphocytes at different maturational stages, indicate that ZAP-70 expression is not a CLL-specific feature among B-cell malignancies and suggest that the absence of ZAP-70 rather than its presence should be considered abnormal for malignant B lymphocytes.

The importance of immunohistochemistry in the differential diagnosis of molar disease.

The differential diagnosis among complete moles, partial moles and hydatidiform abortions may be challenging during routine diagnostic activity. These entities share the histological aspect of enlarged villi, but here we summarize also some peculiar features of all of them. If histology does not clarify this distinction, the immunohistochemistry is the most important tool for pathologists to complete such diagnosis. The correct management of immunohistochemistry and of further possible analysis is also reviewed. Lastly, the most important antibodies, starting from p57, are presented.

Ependymoma with diffuse signet-ring features: report of a case and review of the literature.

Signet-ring cell ependymoma is a rare variant of ependymoma with only seven cases described in literature. Biological behavior and prognosis of this entity are not well-known until now. We present a case of a 49-year-old female with a history of headache and gait instability. Magnetic resonance imaging showed an upper cervical tumor with cystic component and mural nodule. The patient underwent surgery. Microscopically some cells displayed an eccentric nucleus compressed to the periphery by vacuolated cytoplasm. Perivascular pseudorosettes and ependymal rosettes were seen only focally. The cells were positive for glial fibrillary acidic protein and epithelial membrane antigen. The diagnosis was ependymoma with diffuse signet-ring features, grade II according to the World Health Organization. It may be difficult to diagnose this unusual variant of ependymoma especially on small biopsies or frozen sections. A complete examination of the specimen is recommended with immunohistochemical confirmation to rule out potential morphologic mimics, such as metastatic adenocarcinomas and gliomas in the differential diagnosis.

Mediastinal large-B-cell lymphoma with sclerosis: a clinical study of 21 patients.

We report the clinical findings of 21 consecutive patients affected by mediastinal large B-cell lymphoma with sclerosis. This type of lymphoma is a recently described histopathologic entity characterized on clinical grounds by distinctive features, which, according to our series, can be summarized as follows: young age (median, 30 years; range, 15 to 42 years), prevalence of females over males (15 v six), rare occurrence of superficial lymph node enlargement (three of 21 patients), and involvement of unusual extranodal sites (kidney six, adrenal cortex two patients). The clinical course appears to be closely related to treatment. In fact, complete remission (CR) was not obtained in the six patients submitted to conventional cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or CHOP plus bleomycin (CHOP-Bleo) regimens until 1985, as opposed to 13 CRs reached in the 15 patients subsequently treated with more aggressive regimens after 1985 (methotrexate with leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin [MACOP-B], 12 patients; methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone [M-BACOD], two patients; and vincristine, cyclophosphamide, fluorouracil, cytarabine, doxorubicin, methotrexate, and prednisone [F-MACHOP], one patient; plus involved-field radiotherapy, 10 patients). Among the 13 patients who achieved a CR, only one relapse was observed at 10 months. The median overall survival of complete responders after an observation period of 11 to 69 months has not yet been reached, and the event-free survival curve indicates that 90% of patients who achieve CR may be potentially cured.

Serum levels of the soluble form of CD30 molecule as a tumor marker in CD30+ anaplastic large-cell lymphoma.

PURPOSE: To determine serum levels of the soluble form of CD30 molecule (sCD30) in patients with Ki-1/CD30+ anaplastic large-cell lymphoma (ALCL), and to evaluate its correlation with clinical features at presentation and its possible role as a tumor marker to monitor response to treatment and subsequent follow-up. PATIENTS AND METHODS: sCD30 serum levels were measured with an improved commercial sandwich enzyme-linked immunosorbent assay (ELISA) test kit in 24 patients with CD30+ ALCL at diagnosis and in 13 after treatment. RESULTS: Increased values (> 20 U/mL) at diagnosis were observed in 23 of 24 cases (median, 842.5 U/mL; range, 16 to 37,250) as compared with controls (P < .0001). These values were greater than those of 60 stage-matched cases of Hodgkin's disease (HD) (P < .0001). The highest median value was observed in patients with T-cell-type ALCL (1,690 U/mL), with a significant overall difference as compared with B- and null-cell types (P = .004). Phenotype maintained its significance when results were corrected for other parameters, such as age, sex, and stage (P = .03). sCD30 values returned to the normal range in complete remission (CR), but remained increased in one patient who only partially responded to treatment. Subsequent increases of sCD30 levels were recorded in four of four patients after relapse. CONCLUSION: sCD30 appears to be a new biologic serum tumor marker of possible use in the clinical setting of CD30+ ALCL.

Origin of the soluble interleukin-2 receptor in the serum of patients with hairy cell leukemia.

High levels of soluble IL-2 receptor (sIL-2R) are detectable in the serum of HCL patients. To determine the cell source of this molecule, we evaluated the presence of sIL-2R in the supernatants obtained from in vitro cultures of leukemic (hairy cell, HC) and non-leukemic lymphocytes from six untreated HCL patients and from an additional four patients under therapy with rIFN-alpha 2. We demonstrated that cultured HCs at resting conditions were able to spontaneously release the sIL-2R, whereas control enriched B cells did not. This phenomenon was present only when culturing HCs recovered from patients observed at the time of diagnosis but was not observed during treatment with rIFN-alpha 2. Following activation in vitro with a series of different stimulatory agents including BCGF, phorbol myristate acetate, and anti-human IgM antibody, cultured HCs increased their capability to shed the IL-2R molecules. On the other hand, the release of sIL-2R from enriched T cell populations from HCL patients did not significantly differ from the value obtained in controls. Taken together, these findings provide evidence that leukemic B cells represent the main source of sIL-2R in HCL patients and further emphasize the importance of evaluating this parameter as a relevant marker for monitoring the effectiveness of rIFN-alpha 2 therapy.

Alpha (p55) and beta (p75) chains of the interleukin-2 receptor are expressed by AML blasts.

In the present study, we have investigated the leukemic cells obtained from 16 patients with acute myeloid leukemia (AML) at diagnosis for the membrane expression of p55 (alpha) and p75 (beta) interleukin-2 receptor (IL-2R) chains using specific monoclonal antibodies (mAbs), as well as for the presence of their transcripts using Northern blot analysis. In addition, immunoprecipitation of the p75 membrane molecule with TU27 and Mik-beta 1 mAbs was carried out in selected cases. The p75 IL-2R beta transcripts were detected in all cases, whereas the membrane p75 molecule was demonstrable by flow cytometry in three cases. However, data from the immunoprecipitation analysis suggest that the lack of the p75 IL-2R detection by flow cytometry might be caused by the low density of molecules per cell rather than the fact that the specific mRNA is not translated into the p75 surface molecule. In addition, a consistent membrane positivity with an anti-p55/CD25 mAb, present on fresh uncultured blasts in 37.5% of the cases, became detectable after short-term culture in 75% of cases. In each individual case, a strict correlation was found between membrane CD25 reactivity and the expression of p55 mRNA. Taken together, our data suggest that the expression of both alpha (p55) and beta (p75) IL-2R molecules is a common feature of leukemic cells in AML, and provide new arguments for reassessing the possible role of IL-2 in leukemic growth.