Expression of three major classes of glutathione S‐transferases (GSTs), i.e. α, μ and π class, P‐glycoprotein (P‐gp) and multidrug resistance‐associated protein (MRP) were studied in childhood acute lymphoblastic leukaemia (ALL), acute myeloid leukaemia (AML) and normal peripheral blood lymphocytes by flow cytometry. In vitro cytotoxicity of 4‐hydroxy‐ifosfamide (IFOS), daunorubicin (DNR) and prednisolone (PRED) was assessed by the MTT assay. Expression of α, μ and π class GST did not significantly differ between leukaemic cells from 100 initial and 14 unrelated relapse ALL patients (GSTα P =0.26; GSTμ P = 0.09; GSTπ P = 0.13). The expression of GSTα (1.4‐fold, P = 0.0004), GSTπ (1.3‐fold, P = 0.001) and to a lesser extent also GSTμ (1.1‐fold, P = 0.03) was higher in ALL compared with normal peripheral blood lymphocytes. Expression of GSTμ and GSTπ was significantly higher in 18 AML compared with 100 ALL patients at initial diagnosis (respectively 1.3‐fold, P = 0.0005 and 2‐fold, P < 0.0001). In contrast, GSTα was median 2‐fold lower expressed in the AML samples ( P < 0.0001). Expression levels of α, μ and π class GSTs were not related to the degree of resistance to IFOS, DNR and PRED nor to immunophenotype, white blood cell count or age at presentation of childhood ALL. One exception was a remarkably low expression of GSTα in IFOS‐sensitive samples compared with a heterogenous expression in IFOS‐resistant samples ( P = 0.02). Expression of GSTπ, but not of GSTα or GSTμ, weakly correlated with the expression of MRP (Rs 0.36, P = 0.002, n = 74) but not with P‐gp. However, a high expression of both GSTπ and MRP was not associated with in vitro resistance to IFOS, DNR or PRED. The present data suggest that expression of GSTs is not linked to the degree of resistance to IFOS, DNR and PRED or clinical risk factors in childhood ALL. Whether the high expression of GSTμ and GSTπ in AML cells contributes to the relative resistance to IFOS, DNR and PRED compared with ALL samples ( P 0.0001) warrants further study.
To confirm the prognostic value of a drug resistance profile combining prednisolone, vincristine, and l-asparaginase (PVA) cytotoxicity in an independent group of children with acute lymphoblastic leukemia (ALL) treated with a different protocol and analyzed at longer follow-up compared with our previous study of patients treated according to the Dutch Childhood Leukemia Study Group (DCLSG) ALL VII/VIII protocol.Drug resistance profiles were determined in 202 children (aged 1 to 18 years) with newly diagnosed ALL who were treated according to the German Cooperative Study Group for Childhood Acute Lymphoblastic Leukemia (COALL)-92 protocol.At a median follow-up of 6.2 years (range, 4.1 to 9.3 years), the 5-year disease-free survival probability (pDFS) rate +/- SE was 69% +/- 7.0%, 83% +/- 4.4%, and 84% +/- 6.8% for patients with resistant (PVA score 7 to 9), intermediate-sensitive (PVA score 5 to 6), and sensitive (SPVA score 3 to 4) profiles, respectively (sensitive and intermediate-sensitive v resistant, P
Summary Systemic inflammation can be investigated by changes in expression profiles of neutrophil receptors. Application of this technology for analysis of neutrophil phenotypes in diseased tissues is hampered by the absence of information regarding the modulation of neutrophil phenotypes after extravasation to tissues under non-inflammatory conditions. To fill this gap we measured the expression of neutrophil receptors in bronchoalveolar lavage fluid (BALF) and in the peripheral blood of healthy volunteers, which included both smokers and non-smokers. Blood and BALF neutrophils were identified by CD16bright/CD45dim cells, and triple-stained with antibodies directed against integrins, chemokine- and Fcγ-receptors. BALF neutrophils of healthy volunteers showed an activated phenotype characterized by Mac-1 (CD11b)bright, L-selectin (CD62L)dim, intrecellular adhesion molecule 1 (ICAM-1) (CD54)bright, FcγRII (CD32)bright, C5a receptor (CD88)bright and CD66bbright. A similar phenotype was observed for BALF neutrophils of patients affected by sarcoidosis. Furthermore, our results demonstrate a modulated expression of C5a receptor (CD88) and ICAM-1 (CD54) in neutrophils of sarcoidosis patients. In conclusion, our data indicate that neutrophils found in the lung exhibit an activated phenotype under both homeostatic and inflammatory conditions.
Contradictory data have been reported about the prognostic value of myeloid antigen co‐expression (My + ) in childhood acute lymphoblastic leukaemia (ALL). In the present study the methyl thiazol tetrazoliumbromide (MTT) assay was used to compare the in vitro cytotoxicity of 14 drugs between 60 My + (CD13 + and/or CD33 + ) and 107 My − ALL children at initial diagnosis. P‐glycoprotein (P‐gp), multidrug resistance‐associated protein (MRP), major vault protein/lung resistance protein (LRP) and the intracellular daunorubicin concentration were studied by flow cytometry. My + ALL samples were significantly more resistant, i.e. between 1.1‐ and 2.9‐fold, to daunorubicin, doxorubicin, idarubicin, mitoxantrone, vincristine, 6‐thioguanine, 6‐mercaptopurine, teniposide, etoposide and ifosfamide compared with My − ALL samples. My − and My + ALL did not significantly differ in sensitivity to prednisolone, dexamethasone, l ‐asparaginase and cytarabine. Comparable results were found when only common and preB ALL cases were analysed. Drug resistance in My + ALL was not related to increased expression of P‐gp, MRP or LRP compared with My − ALL (ratio My + /My − :P‐gp 0.8, MRP 1.0, LRP 1.1). Accumulation and retention of daunorubicin did not significantly differ between My − and My + ALL cells (ratio My + /My − : accumulation 1.2, retention 1.3). Therefore the nature of drug resistance in My + ALL remains unknown. The lack of prognostic value for My + in childhood ALL may be explained by the responsiveness of My + ALL to glucocorticoids, l ‐asparaginase and cytarabine. In addition, the currently intensive treatment regimens may apply drug doses which are simply high enough to overcome the mild resistance to anthracyclines, mitoxantrone, vincristine, thio‐purines, epipodophyllotoxins and ifosfamide in childhood My + ALL.
