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Background This report describes quality of life (QoL) findings of a randomized study comparing gefitinib with docetaxel in patients with advanced/metastatic pretreated non-small-cell lung cancer. Patients and methods This open-label, phase III study randomized 490 Japanese patients to gefitinib (250 mg/day) or docetaxel (60 mg/m2/3 weeks), with survival as the primary outcome. Preplanned QoL analyses included Functional Assessment of Cancer Therapy-Lung (FACT-L), Trial Outcome Index (TOI) and Lung Cancer Subscale (LCS) improvement rates, and mean change from baseline. Results Gefitinib showed statistically significant benefits over docetaxel in QoL improvement rates (FACT-L 23% versus 14%, P = 0.023; TOI 21% versus 9%, P = 0.002) and mean change from baseline score [mean treatment difference: FACT-L 3.72 points, 95% confidence interval (CI) 0.55–6.89, P = 0.022; TOI 4.31 points, 95% CI 2.13–6.49, P Conclusions Gefitinib improved aspects of QoL over docetaxel, with superior objective response rate and a more favorable tolerability profile and no statistically significant difference in overall survival (although noninferiority was not statistically proven).

Background To compare the efficacy and toxicity of three platinum-based combination regimens against cisplatin plus irinotecan (IP) in patients with untreated advanced non-small-cell lung cancer (NSCLC) by a non-inferiority design. Patients and methods A total of 602 patients were randomly assigned to one of four regimens: cisplatin 80 mg/m(2) on day 1 plus irinotecan 60 mg/m(2) on days 1, 8, 15 every 4 weeks (IP) carboplatin AUC 6.0 min x mg/mL (area under the concentration-time curve) on day 1 plus paclitaxel 200 mg/m(2) on day 1 every 3 weeks (TC); cisplatin 80 mg/m(2) on day 1 plus gemcitabine 1000 mg/m(2) on days 1, 8 every 3 weeks (GP); and cisplatin 80 mg/m(2) on day 1 plus vinorelbine 25 mg/m(2) on days 1, 8 every 3 weeks (NP). Results The response rate, median survival time, and 1-year survival rate were 31.0%, 13.9 months, 59.2%, respectively, in IP; 32.4%, 12.3 months, 51.0% in TC; 30.1%, 14.0 months, 59.6% in GP; and 33.1%, 11.4 months, 48.3% in NP. No statistically significant differences were found in response rate or overall survival, but the non-inferiority of none of the experimental regimens could be confirmed. All the four regimens were well tolerated. Conclusion The four regimens have similar efficacy and different toxicity profiles, and they can be used to treat advanced NSCLC patients.

The purpose of this study was to determine the maximum tolerated dose (MTD) and recommended dose (RD) of pemetrexed with folate and vitamin B12 supplementation (FA/VB(12)) in Japanese patients with solid tumours and to investigate the safety, efficacy, and pharmacokinetics of pemetrexed. Eligible patients had incurable solid tumours by standard treatments, a performance status 0-2, and adequate organ function. Pemetrexed from 300 to 1,200 mg m(-2) was administered as a 10-min infusion on day 1 of a 21-day cycle with FA/VB(12). Totally, 31 patients were treated. Dose-limiting toxicities were alanine aminotransferase (ALT) elevation at 700 mg m(-2), and infection and skin rash at 1,200 mg m(-2). The MTD/RD were determined to be 1,200/1,000 mg m(-2), respectively. The most common grade 3/4 toxicities were neutropenia (grade (G) 3:29, G4:3%), leucopenia (G3:13, G4:3%), lympopenia (G3:13%) and ALT elevation (G3:13%). Pemetrexed pharmacokinetics in Japanese were not overtly different from those in western patients. Partial response was achieved for 5/23 evaluable patients (four with non-small cell lung cancer (NSCLC) and one with thymoma). The MTD/RD of pemetrexed were determined to be 1,200/1,000 mg m(-2), respectively, that is, a higher RD than without FA/VB(12) (500 mg m(-2)). Pemetrexed with FA/VB(12) showed a tolerable toxicity profile and potent antitumour activity against NSCLC in this study.

Background The purpose of this study was to evaluate the toxicity and antitumor effect of cisplatin, irinotecan and etoposide combinations on two schedules, arms A and B, for previously untreated extensive small-cell lung cancer (E-SCLC), and to select the right arm for phase III trials. Patients and methods Sixty patients were randomized to receive either arm A (cisplatin 25 mg/m2 day 1, weekly for 9 weeks, irinotecan 90 mg/m2 day 1, on weeks 1, 3, 5, 7 and 9, and etoposide 60 mg/m2 days 1–3, on weeks 2, 4, 6, 8), or arm B (cisplatin 60 mg/m2 day 1, irinotecan 60 mg/m2 days 1, 8, 15, and etoposide50 mg/m2 days 1–3, every 4 weeks for four cycles). Prophylactic granulocyte colony-stimulating factor support was provided in both arms. Results Full cycles were delivered to 73% and 70% of patients in arms A and B, respectively. Incidences of grade 3–4 neutropenia, anemia, thrombocytopenia, infection and diarrhea were 57, 43, 27, 7 and 7%, respectively, in arm A, and 87, 47, 10, 13 and 10%, respectively, in arm B. A treatment-related death developed in one patient in arm A. Complete and partial response rates were 7% and 77%, respectively, in arm A, and 17% and 60%, respectively, in arm B. Median survival time was 8.9 months in arm A, and 12.9 months in arm B. Conclusions Arm B showed a promising complete response rate and median survival with acceptable toxicity in patients with E-SCLC, and should be selected for the investigational arm in phase III trials.

This mini-review is a compendium of the degradation of a man-made compound, 6-aminohexanoate-oligomer, in Flavobacterium strains. The results are summarized as follows: 1. Three enzymes, 6-aminohexanoate-cyclic-dimer hydrolase (EI), 6-aminohexanoate-dimer hydrolase (EII), and endotype 6-aminohexanoate-oligomer hydrolase (EIII) were responsible for degradation of the oligomers. 2. The genes coding these enzymes were located on pOAD2, one of three plasmids harbored in Flavobacterium sp. KI72, which comprised 45,519 bp. 3. The gene coding the EII' protein (a protein having 88% homology with EII) and five IS6100 elements were identified on pOAD2. 4. The specific activity of EII was 200-fold higher than that of EII'. However, altering two amino acid residues in the EII' enzyme enhanced the activity of EII' to the same level as that of the EII enzyme. 5. The deduced amino acid sequences from eight regions of pOAD2 had significant similarity with the sequences of gene products such as oppA-F (encoding oligopeptide permease), ftsX (filamentation temperature sensitivity), penDE (isopenicillin N-acyltransferase) and rep (plasmid replication). 6. The EI and EII genes of Pseudomonas sp. NK87 (another nylon oligomer-degrading bacterium) were also located on plasmids. 7. Through selective cultivation using nylon oligomers as a sole source of carbon and nitrogen, two strains which initially had no metabolic activity for nylon oligomers, Flavobacterium sp. KI725 and Pseudomonas aeruginosa PAO1, were given the ability to degrade xenobiotic compounds. A molecular basis for the adaptation of microorganisms toward xenobiotic compounds was described.

A study was undertaken to determine the maximum tolerated dose, the dose-limiting toxicities, and the response rate of irinotecan administered weekly with concurrent thoracic radiation therapy in patients with locally advanced non-small-cell lung cancer. In a phase I/II clinical trial, patients with histologically documented, surgically unresectable stage IIIA or IIIB non-small cell lung cancer (NSCLC) were enrolled. Irinotecan was administered as a 90 min intravenous infusion once weekly for 6 weeks. The starting dose was 30 mg m−2 and dose escalation was done in 15 mg m−2 increments. Dose-limiting toxicity was defined as grade 3 nonhaematologic toxicity (excluding nausea, vomiting and alopecia) or grade 4 haematologic toxicity according to the WHO criteria. Radiation was delivered to the primary tumour and regional lymph nodes (40 Gy), followed by a boost to the primary tumour (20 Gy). Twenty-seven patients were entered into this study at three irinotecan dose levels (30, 45 and 60 mg m−2). Twenty-six eligible patients were evaluated for toxic effects and clinical outcome. Severe oesophagitis, pneumonitis, and diarrhoea occurred at 45 and 60 mg m−2. Three of the five patients given 60 mg m−2 developed grade 3 or 4 oesophagitis and pneumonitis. In addition, one patient died of pneumonitis after completing therapy at 45 mg m−2 in the phase II study. The objective response rate was 76.9% (95% CI, 53.0–88.9%). Oesophagitis, pneumonitis, and diarrhoea are the dose-limiting toxicities of weekly irinotecan combined with thoracic irradiation. The maximum tolerated dose and the dose for the phase II study were 60 and 45 mg m−2 wk−1, respectively. This combined therapy for locally advanced non-small cell lung cancer is promising and shows acceptable toxicity. © 1999 Cancer Research Campaign

The importance of the dose intensity of chemotherapy in achieving maximal therapeutic effect has recently been reported for several chemosensitive malignant diseases, with Murray et al. reporting that intensive weekly chemotherapy using the cisplatin, vincristine, doxorubicin, and etoposide (CODE) regimen in small-cell lung cancer (SCLC) is very effective. However, leukopenia is the major obstacle to delivering the planned dose in intensive regimens. Therefore, we investigated whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) could allow full drug doses to be given as scheduled, thereby improving the final outcome. Extensive-stage (ES) SCLC patients were randomized to receive either CODE alone or CODE with rhG-CSF, with the CODE regimen consisting of cisplatin given i.v. at 25 mg/m2 weekly for 9 weeks; vincristine given i.v. at 1 mg/m2 during weeks 1, 2, 4, 6, and 8; and doxorubicin given i.v. at 40 mg/m2 and etoposide given i.v. at 80 mg/m2 for 3 days during weeks 1, 3, 5, 7, and 9, rhG-CSF at 50 micrograms/m2 was given s.c. on the days on which cytotoxic drugs were not given. From May 1989 to September 1991; 64 patients were enrolled in the study, of whom 63 were analyzable (31 for CODE alone and 32 for CODE with rhG-CSF). No difference in any of the patients' characteristics except gender was found between the two groups. The complete response (CR) rate was 34% in the CODE with rhG-CSF group and 23% in the CODE alone group; the median survival was 59 and 32 weeks, respectively, in these groups (P = 0.004). Therefore CODE with rhG-CSF improved the survival of ES SCLC patients. On the basis of these results a phase III study to determine whether CODE with rhG-CSF would increase survival as compared to the standard regimen in ES SCLC was designed by the Japan Clinical Oncology Group.

Summary Purpose We compared the activity and toxicity of vinorelbine (VRB) and vindesine (VDS) in a randomized crossover study in patients with previously untreated stages IIIB or IV non-small-cell lung cancer (NSCLC). Patients and methods Two hundred four patients were assessable for response and toxicity. VRB was administered at a dose of 25 mg/m2 weekly and VDS at a dose of 3 mg/m2 weekly. Patients who failed to respond after 4 cycles of initial monotherapy were switched to a combination chemotherapy (VRB → VDS + cisplatin (P) or VDS ← VRB + P). Results Objective response was observed in 31.1% of patients in the VRB arm versus 8.9% of those in the VDS arm (P = 0.0002). The median duration of response to VRB was 18.5+ weeks (range, 7.9 to 107.5+ weeks) compared with 11.7+ weeks (range, 6.0 to 35.0+ weeks) for VDS. Of the 69 patients who failed to respond to initial monotherapy, 33 in the VRB group who subsequently received VDS + P did not respond and 13 (26.5%) of 49 initially on VDS who received subsequent VRB + P responded. The rates of grades 3 and 4 leukopenia were similar in the two monotherapy arms (VRB, 55.3% vs. VDS, 48.5%). However, grade 3 anemia was more frequent in the patients on VRB than in those on VDS. The incidence of peripheral neurotoxicity was significantly higher with VDS than with VRB (P = 0.002), but VRB induced a slightly higher rate of local cutaneous reaction than VDS (P = 0.012). With the combination of cisplatin and these vinca alkaloids, peripheral neurotoxicity was less frequent in the VRB group than in the VDS group. Conclusion Our results demonstrate that VRB yields a higher response rate than VDS in stage IIIB or IV NSCLC, with the same extent of toxicity in terms of leukocytopenia. The peripheral neurotoxic effects were also milder with VRB than with VDS. In second-line chemotherapy, there was a notable difference in response between the VRB + P and VDS + P regimens.

We have conducted a Phase I trial to determine the maximum tolerated dose of CPT-11 together with a fixed dose of cisplatin in patients with advanced lung cancer, and the dose-limiting toxicities of this combination. Fourteen previously untreated patients with stage IIIB or IV disease were treated with CPT-11 (90-min intravenous infusion on days 1, 8, and 15) plus cisplatin (60 mg m-2, intravenously on day 1). The starting dose of CPT-11 was 60 mg m-2, and diarrhea was the dose-limiting toxicity at the 90 mg m-2 dose level. All three patients (all four cycles) given 90 mg m-2 of CPT-11 experienced grade 3 diarrhea. Hematologic toxicity was relatively mild. Elimination of CPT-11 was biphasic with a mean (+/- s.d.) beta half-life of 11.36 +/- 7.26 h. The mean terminal half-life of the major metabolite (7-ethyl-10-hydroxycamptothecin; SN-38) was 22.13 +/- 13.28 (s.d.) h, and modest escalation of the CPT-11 dose from 80 mg m-2 to 90 mg m-2 resulted in a statistically significant apparent increase in the plasma concentrations of SN-38. There were one complete response (7%) and five partial responses (36%) among the 14 patients for an overall response rate of 43%. The recommended dose for Phase II studies is 80 mg m-2 of CPT-11 and 60 mg m-2 of cisplatin.

PURPOSE The purpose of this study was to determine the maximum-tolerated dose and the dose-limiting toxicities of CPT-11, a new derivative of camptothecin, in combination with a fixed dose of cisplatin in patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS Twenty-seven previously untreated patients with stage IIIB or IV NSCLC were assessable for toxicity, and 26 were assessable for response. The initial dose of CPT-11 was 30 mg/m2 given as a 90-minute intravenous (IV) infusion on days 1, 8, and 15 in combination with cisplatin (80 mg/m2 IV on day 1) given every 4 weeks. The dose of CPT-11 was escalated in increments of 10 mg/m2 until severe or life-threatening toxic effects were observed. RESULTS Significant toxicity was infrequent up to 60 mg/m2 of CPT-11. The maximum-tolerated toxicity was reached at a dose of 70 mg/m2. Three of six patients either had leukocyte count nadirs of less than 2,000/microL or experienced grade 4 diarrhea during the first cycle of therapy at 70 mg/m2. The major toxic effects were leukopenia and diarrhea. There were 14 partial responses (54%) among the 26 patients. CONCLUSIONS A combination of CPT-11 and cisplatin seems to be effective against NSCLC with acceptable toxicities. The recommended dose for phase II studies is 60 mg/m2 of CPT-11 on days 1, 8, and 15, and 80 mg/m2 of cisplatin on day 1 every 4 weeks.

Background This phase I dose-escalating study investigated the tolerability and toxicity of the selective epidermal growth factor receptor tyrosine kinase inhibitor gefitinib (‘Iressa’, ZD1839) in Japanese patients with solid tumors. Thirty-one patients were included. Patients and methods Patients initially received a single oral dose of gefitinib followed by 10–14 days of observation. Oral gefitinib was subsequently administered on 14 consecutive days, every 28 days. Dose escalation was from 50 mg/day to a maximum of 925 mg/day or dose-limiting toxicity (DLT). Results Most adverse events were mild (grade 1/2); the most frequent were an acne-like rash and gastrointestinal effects. Two of six patients at 700 mg/day had DLT; no further dose escalation occurred. Cmax was reached within 3–7 h and exposure to gefitinib increased with dose. Mean terminal half-life following multiple dosing was 50.1 h (range 27.8–79.7 h). A partial response (duration 35–361 days) was observed in five of the23 patients with non-small-cell lung cancer over a range of doses (225–700 mg/day), and seven patients with a range of tumors had disease stabilization (duration 40–127 days). Conclusions In conclusion, gefitinib showed a favorable tolerability profile in Japanese patients. The safety profile, pharmacokinetic parameters and antitumor activity observed in our study are comparable to those observed in patients from the USA and Europe.

We compared the activity of vinorelbine (VRB) and vindesine (VDS) in a randomized crossover study in patients with previously untreated stages IIIB or IV non-small-cell lung cancer (NSCLC).Two hundred four patients were assessable for response and toxicity. VRB was administered at a dose of 25 mg/m2 weekly and VDS at a dose of 3 mg/m2 weekly. Patients who failed to respond after 4 cycles of initial monotherapy were switched to a combination chemotherapy (VRB--VDS + cisplatin (P) or VDS--VRB + P).Objective response was observed in 31.1% of patients in the VRB arm versus 8.9% of those in the VDS arm (P = 0.0002). The median duration of response to VRB was 18.5+ weeks (range, 7.9 to 107.5+ weeks) compared with 11.7+ weeks (range, 6.0 to 35.0+ weeks) for VDS. Of the 69 patients who failed to respond to initial monotherapy, 33 in the VRB group who subsequently received VDS + P did not respond and 13 (26.5%) of 49 initially on VDS who received subsequent VRB + P responded. The rates of grades 3 and 4 leukopenia were similar in the two monotherapy arms (VRB, 55.3% vs. VDS, 48.5%). However, grade 3 anemia was more frequent in the patients on VRB than in those on VDS. The incidence of peripheral neurotoxicity was significantly higher with VDS than with VRB (P = 0.002), but VRB induced a slightly higher rate of local cutaneous reaction than VDS (P = 0.012). With the combination of cisplatin and these vinca alkaloids, peripheral neurotoxicity was less frequent in the VRB group than in the VDS group.Our results demonstrate that VRB yields a higher response rate than VDS in stage IIIB or IV NSCLC, with the same extent of toxicity in terms of leukocytopenia. The peripheral neurotoxic effects were also milder with VRB than with VDS. In second-line chemotherapy, there was a notable difference in response between the VRB + P and VDS + P regimens.

Background The prognosis of gastric cancer with peritoneal metastasis is extremely poor. Neither systemic chemotherapy nor surgery alone prolongs survival of patients significantly. Methods Patients diagnosed with advanced gastric cancer underwent staging laparoscopy and received chemotherapy when peritoneal dissemination and/or cancer cells on peritoneal cytology were confirmed. The chemotherapy regimen consisted of S-1, weekly intravenous and intraperitoneal paclitaxel, which was verified in our phase II trial (Ann Oncol 2009). S-1 was administered at 80 mg/m2/day for 14 consecutive days, followed by 7 days rest. Paclitaxel was administered intravenously at 50 mg/m2 and intraperitoneally at 20 mg/m2 on days 1 and 8. Clinical response of chemotherapy was assessed by computed tomography, gastroendoscopy, peritoneal cytology and second-look laparoscopy. Radical gastrectomy was carried out when macroscopic curative resection was made achievable by chemotherapy. Chemotherapy was restarted after operation as soon as possible. Overall survival, relapse free survival, morbidity and mortality of gastrectomy were evaluated. Results Out of 100 patients with peritoneal metastasis who received chemotherapy, 60 patients underwent gastrectomy after response to chemotherapy, including 54 with macroscopic metastasis and 6 with positive peritoneal cytology only. A median of three courses were administered preoperatively (range 1–16). Total or distal gastrectomy with lymphnode dissection was carried out in 54 or 6 patients, respectively. The median survival time was 34.5 months. The median relapse-free survival was 16.7 months. The first site of relapse was the peritoneum in 24 patients and the other organ site in 17 patients. Postoperative complications included anastomotic leakage and pancreatic fistula in two patients each, which were healed conservatively. There were no treatment-related deaths. Conclusions Gastrectomy combined with S-1, intravenous and intraperitoneal paclitaxel is safe and active for gastric cancer patients with peritoneal metastasis.

PURPOSE For patients with locally advanced (stage III) non-small-cell lung cancer (NSCLC), radiotherapy (RT) has been used conventionally for many years. Few prospective trials have determined the role of RT. Recently, chemotherapy (CT) has been shown to produce excellent responses in regionally advanced disease. We therefore conducted a randomized trial using cisplatin (P)-based CT regimens with or without thoracic irradiation. PATIENTS AND METHODS We randomly assigned 92 patients with locally advanced NSCLC to receive one of three arms of P-based combination chemotherapy: vindesine (V) plus P, mitomycin (M) plus V plus P, or etoposide (E) plus P alternating with V plus M. After two cycles of CT, patients were reevaluated and those with stage III were again randomized to receive RT or not. RT consisted of 50 to 60 Gy in 5 to 6 weeks; 2 Gy was delivered once daily in conventional fractions. RESULTS Sixty-three patients were included in the second randomization. The patients in the CT/RT group (n = 32) and CT-alone group (n = 31) were comparable in terms of age, sex, performance status, histologic features, stage of disease, and induction CT regimen. The median durations of survival were similar for the two groups (461 days in CT/RT group and 447 days in CT-alone group). The survival rate in the CT/RT group was 58% at 1 year, 36% at 2 years, and 29% at 3 years, as compared with 66%, 9%, and 3% at 1, 2, and 3 years, respectively, in the CT-alone group. One patient in the CT/RT group died of pneumonitis, but there were no CT-related deaths. CONCLUSION In locally advanced NSCLC, P-based combination CT followed by chest irradiation significantly increases the number of long-term survivors as compared with CT alone. RT to bulky disease in the thorax is thus an important part of combined modality therapy, and a necessary part of further studies in locally advanced disease.

We characterized the nuclear proteins with specific binding ability against c-myc gene by gel-shift assay in cell extracts of peripheral blood mononuclear cells (PBMC) from SLE patients and SLE-prone mice with use of distinct c-myc fragments. With the fragment named Fmyc in our experiments, two kinds of complexes which we call C1 and C2 respectively were found in PBMC from SLE patients and SLE-prone mice. The C1 was shown to be inducible in PBMC from healthy persons without nascent protein synthesis after lectin binding to the cell and found to be elevated in the SLE patients and in all of the established cell lines we examined. The C2 seemed to be peculiar to SLE subjects. The binding site of the C1 factor (C1F) and C2 factor (C2F) which forms C1 and C2 respectively with Fmyc appeared to be common and were found to reside at 51 kbp sequence (from XhoI to Sau3A) of exon I of c-myc gene. Interestingly, XhoI site of the binding site was highly demethylated in PBMC of SLE patients as compared with healthy persons. The roles of these binding factors for the pathogenesis of SLE are discussed.

In the present paper we demonstrate that there is an antigenic determinant common to two different types of human leukaemia-associated antigens, i.e. human thymus leukaemia-associated (HTL) antigens and common acute lymphoblastic leukaemia (cALL) antigen. In addition, there are distinct antigenic determinants which are unique to the HTL antigens or to the cALL antigen. The new, common antigenic determinant will be useful as a new differentiation marker of human haematopoietic cells as well as a new leukaemia-associated marker. In the present study, we used several different anti-human leukaemia antisera which include those prepared by immunizing rabbits (Nos. 7549 and 7550) with purified HTL antigens. The antisera 7549 and 7550, without any absorption, showed strong specificity as well as strong antibody activity toward leukaemia cells. These are the first anti-human leukaemia antisera, except for the monoclonal hybridoma antibodies, that show good specificity for leukaemia cells without prior absorption.

Female F1 mice (BDF1: C57BL/6 x DBA/2, BCF1: C57BL/6 x C3H/HeN, BBF1: C57BL/6 x BALB/c) were preimmunized with rat erythrocytes and then received splenic T cells from parental female C57BL/6 mice injected with hydrocortisone acetate before killing. In BDF1 and BCF1 mice, direct Coombs' test (DCT) positivity persisted for more than 4 months in almost all mice. They also showed haematological sign of anaemia, and the survival of infused 51Cr-labelled parental C57BL/6 erythrocytes was reduced. In BBF1 mice, DCT positivity returned to negative within 2 months. Autoantibodies were eluted from DCT-positive erythrocytes and their specificities were examined. They were capable of binding equally well to erythrocytes from all strains of mice tested, including the donor mice. They also cross-reacted with rat erythrocytes but not with sheep, rabbit or human erythrocytes. Isotypes of the autoantibodies eluted were also examined. Interestingly, isotypes of the autoantibodies obtained from individual mice were confined to one or other subclass of IgG isotype: IgG1, IgG2a or IgG2b.

This study examined the phosphorylation of cytoplasmic and nuclear proteins in peripheral blood mononuclear cells (PBMC) of systemic lupus erythematosus (SLE) patients. The cytoplasmic and nuclear protein kinase activity in PBMC from SLE patients was at least five-fold higher than that of normal healthy subjects. PBMC of SLE patients produced different nuclear endogenous substrates on phosphorylation and also displayed distinct protein kinase activity. Nuclear phosphoproteins, with human PBMC DNA-binding ability, of 38 kD and 70 kD were detected from both SLE patients and normal healthy subjects, while the 40 kD phosphoprotein, with tyrosine as the main phosphorylation residue, was found only in SLE patients. Other nuclear phosphoproteins, and most of the detected cytoplasmic phosphoproteins, were present in higher levels in both normal PBMC with mitogen stimulation, such as PHA, and SLE PBMC. The expression level of the 40 kD nuclear phosphotyrosyl-protein showed a positive correlation with the clinical disease activity of SLE. These results suggest that PBMC from SLE patients had distinct tyrosine protein kinase (TPK) activity and/or a different endogenous substrate of nuclear DNA-binding proteins in tyrosine phosphorylation. The possible significance of tyrosine phosphorylation in PBMC of SLE patients in the pathogenesis, and its clinical meaning, are discussed.