Impact of individualized treatment on recovery from fatigue and return to work in survivors of advanced-stage Hodgkin's lymphoma: results from the randomized international GHSG HD18 trial

BACKGROUND

Persisting cancer-related fatigue impairs health-related quality of life (HRQoL) and social reintegration in patients with Hodgkin's lymphoma (HL). The GHSG HD18 trial established treatment de-escalation for advanced-stage HL guided by positron emission tomography after two cycles (PET-2) as new standard. Here, we investigate the impact of treatment de-escalation on long-term HRQoL, time to recovery from fatigue (TTR-F), and time to return to work (TTR-W).

PATIENTS AND METHODS

Patients received European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30) and life situation questionnaires at baseline, interim, end of treatment, and yearly follow-up. TTR-F was defined as time from the end of chemotherapy until the first fatigue score <30. TTR-W was analyzed in previously working or studying patients and measured from the end of treatment until the first documented work or education. We compared duration of treatment on TTR-F and TTR-W using Cox proportional hazards regression adjusted for confounding variables.

RESULTS

HRQoL questionnaires at baseline were available in 1632 (83.9%) of all randomized patients. Overall, higher baseline fatigue and age were significantly associated with longer TTR-F and TTR-W and male sex with shorter TTR-W. Treatment reduction from eight to four chemotherapy cycles led to a significantly shorter TTR-F [hazard ratio (HR) 1.41, P = 0.008] and descriptively shorter TTR-W (HR 1.24, P = 0.084) in PET-2-negative patients. Reduction from six to four cycles led to non-significant but plausible intermediate accelerations. The addition of rituximab caused significantly slower TTR-F (HR 0.70, P = 0.0163) and TTR-W (HR 0.64, P = 0.0017) in PET-2-positive patients. HRQoL at baseline and age were the main determinants of 2-year HRQoL.

CONCLUSIONS

Individualized first-line treatment in patients with advanced-stage HL considerably shortens TTR-F and TTR-W in PET-2-negative patients. Our results support the use of response-adapted shortened treatment duration for patients with HL.

R-miniCHOP versus R-CHOP in elderly patients with diffuse large B-cell lymphoma: A propensity matched population-based study

For elderly frail patients with diffuse large B-cell lymphoma (DLBCL), an attenuated chemo-immunotherapy strategy of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-miniCHOP) was introduced as a treatment option as from 2014 onward in the Netherlands. Although R-miniCHOP is more tolerable, reduction of chemotherapy could negatively affect survival compared to R-CHOP. The aim of this analysis was to assess survival of patients treated with R-miniCHOP compared to R-CHOP. DLBCL patients ≥65 years, newly diagnosed in 2014-2020, who received ≥1 cycle of R-miniCHOP or R-CHOP were identified in the Netherlands Cancer Registry, with survival follow-up through 2022. Patients were propensity-score-matched for baseline characteristics. Main endpoints were progression-free survival (PFS), overall survival (OS), and relative survival (RS). The use of R-miniCHOP in DLBCL increased from 2% in 2014 to 15% in 2020. In total, 384 patients treated with R-miniCHOP and 384 patients treated with R-CHOP were included for comparison (median age; 81 years, stage 3-4; 68%). The median number of R-(mini)CHOP cycles was 6 (range, 1-8). The 2-year PFS, OS and RS were inferior for patients treated with R-miniCHOP compared to R-CHOP (PFS 51% vs. 68%, p < .01; OS 60% vs. 75%, p < .01; RS 69% vs. 86%, p < .01). In multivariable analysis, patients treated with R-miniCHOP had higher risk of all-cause mortality compared to patients treated with R-CHOP (HR 1.73; 95%CI, 1.39-2.17). R-miniCHOP is effective for most elderly patients. Although survival is inferior compared to R-CHOP, the use of R-miniCHOP as initial treatment is increasing. Therefore, fitness needs to be carefully weighed in treatment selection.

Treatment-specific risk of subsequent malignant neoplasms in five-year survivors of diffuse large B-cell lymphoma

BACKGROUND

The introduction of rituximab significantly improved the prognosis of diffuse large B-cell lymphoma (DLBCL), emphasizing the importance of evaluating the long-term consequences of exposure to radiotherapy, alkylating agents and anthracycline-containing (immuno)chemotherapy among DLBCL survivors.

METHODS

Long-term risk of subsequent malignant neoplasms (SMNs) was examined in a multicenter cohort comprising 2373 5-year DLBCL survivors treated at ages 15-61 years in 1989-2012. Observed SMN numbers were compared with expected cancer incidence to estimate standardized incidence ratios (SIRs) and absolute excess risks (AERs/10 000 person-years). Treatment-specific risks were assessed using multivariable Cox regression.

RESULTS

After a median follow-up of 13.8 years, 321 survivors developed one or more SMNs (SIR 1.5, 95% CI 1.3-1.8, AER 51.8). SIRs remained increased for at least 20 years after first-line treatment (SIR ≥20-year follow-up 1.5, 95% CI 1.0-2.2, AER 81.8) and were highest among patients ≤40 years at first DLBCL treatment (SIR 2.7, 95% CI 2.0-3.5). Lung (SIR 2.0, 95% CI 1.5-2.7, AER 13.4) and gastrointestinal cancers (SIR 1.5, 95% CI 1.2-2.0, AER 11.8) accounted for the largest excess risks. Treatment with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin versus ≤2250 mg/m2/≤150 mg/m2, respectively, was associated with increased solid SMN risk (hazard ratio 1.5, 95% CI 1.0-2.2). Survivors who received rituximab had a lower risk of subdiaphragmatic solid SMNs (hazard ratio 0.5, 95% CI 0.3-1.0) compared with survivors who did not receive rituximab.

CONCLUSION

Five-year DLBCL survivors have an increased risk of SMNs. Risks were higher for survivors ≤40 years at first treatment and survivors treated with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin, and may be lower for survivors treated in the rituximab era, emphasizing the need for studies with longer follow-up for rituximab-treated patients.

OS03.6.A Rituximab in primary CNS lymphoma - long term follow-up of the phase III HOVON 105/ALLG NHL 24 Study

Background

The efficacy of rituximab in Primary CNS Lymphoma (PCNSL) is still under debate. We performed an international randomized phase III study to investigate the efficacy of rituximab when added to methotrexate, BCNU, teniposide and prednisolone (MBVP) in PCNSL. The primary endpoint, event-free survival (EFS) at one year, was similar in both treatment groups and was previously reported (Bromberg et al, Lancet Oncology 2019; 20: 216-228). Here we present long-term follow up results after a median follow-up of 82 months.

Material and Methods

between August 2010 and May 2016 200 newly-diagnosed, non-immunocompromised patients with PCNSL aged 18-70 years and WHO performance status 0-3 were randomized between treatment with MBVP chemotherapy with (arm B) or without (arm A) rituximab. The rituximab was given weekly in the first MBVP cycle, fortnightly in the second (in total 6 rituximab administrations). Responsive patients received consolidation with high-dose cytarabine, and patients aged ≤ 60 were subsequently treated with low-dose WBRT if in CR/CRu; in case of PR with an additional boost on the tumor. Patients &gt; 60 were not irradiated. All patients gave written informed consent.

Results

The modified intention-to-treat (m-ITT) population consisted of 199 eligible patients, 55% were men. The median age was 61 yrs (range 26-70), the median WHO performance status 1 (range 0-3). The primary endpoint EFS at one year was 49% (95% CI 39-58)(MBVP) vs 55% (95% CI 44-64) (R-MBVP). The EFS at 5 years was 25% (17-34) vs 36% (27-46) respectively, hazard ratio (HR) 0.85, 95% CI 0.61-1.18, p=0.33 (adjusted for age and WHO performance status). The progression-free survival (PFS) at one and 5 years were 58% (47-67) and 29% (21-39) (MBVP) and 65% (54-73) and 43% (33-53) (R-MBVP) ) (HR 0.73, 95% CI 0.52-1.02, p=0.07). 80 patients were still alive. Overall survival (OS) at 5 years for MBVP and R-MBVP was 49% (39-59) and 53% (43-63) respectively. A total of 111 patients had progression or relapse, 63 after MBVP and 48 after R-MBVP. 79% of these patients received further treatment. The median OS after progression/relapse was 9.7 months (5.9-19.9) in the MBVP arm, and 6.1 months (2.4-13.1) in the R-MBVP arm (HR 1.25, 95% CI 0.83-1.87, p=0.29). 119 patients died, 64 in the MBVP arm and 55 in the R-MBVP arm. Causes of death were PCNSL in 69% of the patients (both arms), complication of treatment (6% vs 5%), secondary malignancy (5% vs 2%) and other or unknown causes (20% vs 24%). Age was the strongest prognostic factor for EFS, PFS and OS in multivariate analysis.

Conclusion

in the modified-ITT population we found no statistically significant benefit of the addition of rituximab to MBVP on EFS, PFS and OS in patients with PCNSL, even after a long follow-up of median 82 months. Therefore, the results of this study do not support the use of rituximab with MBVP in the treatment of primary CNS lymphoma.

Cost-Effectiveness of Shortening Treatment Duration Based on Interim PET Outcome in Patients With Diffuse Large B-cell Lymphoma

BACKGROUND

Guideline recommendations for diffuse large-B-cell lymphoma (DLBCL) treatment are shifting from long to short treatment duration, although it is still unclear whether shortening treatment duration does not cause any harm. As interim PET (I-PET) has high negative predictive value for progression, we evaluated the cost-effectiveness of shortening treatment duration dependent on I-PET result.

MATERIALS AND METHODS

We developed a Markov cohort model using the PET Re-Analysis (PETRA) database to evaluate a long treatment duration (LTD) strategy, ie 8x R-CHOP or 6x R-CHOP plus 2 R, and a short treatment duration (STD) strategy, ie 6x R-CHOP. Strategies were evaluated separately in I-PET2 positive and I-PET2 negative patients. Outcomes included total costs and quality-adjusted life-years (QALYs) per patient (pp) from a societal perspective. Net monetary benefit (NMB) per strategy was calculated using a willingness-to-pay threshold of €50,000/QALY. Robustness of model predictions was assessed in sensitivity analyses.

RESULTS

In I-PET2 positive patients, shortening treatment duration led to 50.4 additional deaths per 1000 patients. The STD strategy was less effective (-0.161 [95%CI: -0.343;0.028] QALYs pp) and less costly (-€2768 [95%CI: -€8420;€1105] pp). Shortening treatment duration was not cost-effective (incremental NMB -€5281). In I-PET2 negative patients, shortening treatment duration led to 5.0 additional deaths per 1000 patients and a minor difference in effectiveness (-0.007 [95%CI: -0.136;0.140] QALY pp). The STD strategy was less costly (-€5807 [95%CI: -€10,724;-€2685] pp) and led to an incremental NMB of €5449, indicating that it is cost-effective to shorten treatment duration. Robustness of these findings was underpinned by deterministic and probabilistic sensitivity analyses.

CONCLUSION

Treatment duration should not be shortened in I-PET2 positive patients whereas it is cost-effective to shorten treatment duration in I-PET2 negative patients.

Aberrant patterns of PET response during treatment for DLBCL patients with MYC gene rearrangements

Purpose

MYC gene rearrangements in diffuse large B-cell lymphoma (DLBCL) patients are associated with poor prognosis. Our aim was to compare patterns of 2[¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography computed tomography (PET/CT) response in MYC + and MYC- DLBCL patients.

Methods

Interim PET/CT (I-PET) and end of treatment PET/CT (EoT-PET) scans of 81 MYC + and 129 MYC- DLBCL patients from 2 HOVON trials were reviewed using the Deauville 5-point scale (DS). DS1-3 was regarded as negative and DS4-5 as positive. Standardized uptake values (SUV) and metabolic tumor volume (MTV) were quantified at baseline, I-PET, and EoT-PET. Negative (NPV) and positive predictive values (PPV) were calculated using 2-year overall survival.

Results

MYC + DLBCL patients had significantly more positive EoT-PET scans than MYC- patients (32.5 vs 15.7%, p = 0.004). I-PET positivity rates were comparable (28.8 vs 23.8%). In MYC + patients 23.2% of the I-PET negative patients converted to positive at EoT-PET, vs only 2% for the MYC- patients (p = 0.002). Nine (34.6%) MYC + DLBCL showed initially uninvolved localizations at EoT-PET, compared to one (5.3%) MYC- patient. A total of 80.8% of EoT-PET positive MYC + patients showed both increased lesional SUV and MTV compared to I-PET. In MYC- patients, 31.6% showed increased SUV and 42.1% showed increased MTV. NPV of I-PET and EoT-PET was high for both MYC subgroups (81.8–94.1%). PPV was highest at EoT-PET for MYC + patients (61.5%).

Conclusion

MYC + DLBCL patients demonstrate aberrant PET response patterns compared to MYC- patients with more frequent progression during treatment after I-PET negative assessment and new lesions at sites that were not initially involved.

Trial registration number and date of registration

HOVON-84: EudraCT: 2006–005,174-42, retrospectively registered 01–08-2008. HOVON-130: EudraCT: 2014–002,654-39, registered 26–01-2015

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05498-7.

POS0809 A BIOMARKER PROFILE AIDING AN EARLY DIAGNOSIS OF GIANT CELL ARTERITIS

Background:

Diagnosing patients with giant cell arteritis (GCA) remains difficult. Due to its non-specific symptoms, it is challenging to identify GCA in patients presenting with polymyalgia rheumatica (PMR), which is a more common disease (1). In addition, commonly used acute-phase markers fail to discriminate between GCA patients and (infectious) mimicry patients.

Objectives:

To investigate a selection of biomarkers for their utility in the accurate diagnosis of GCA in two cohorts.

Methods:

Treatment-naïve GCA patients participated in the Aarhus GCA/PMR cohort (N=52) and the Groningen GPS cohort (N=48). Symptoms and biomarker levels were compared to patients presenting phenotypically as isolated PMR, disease controls and healthy controls (HCs). Diagnosis or exclusion of diagnosis of GCA was based on clinical assessment and in the majority of cases aided by imaging. Serum/plasma levels of 12 biomarkers were measured by ELISA or Luminex.

Results:

In both the Aarhus and the GPS cohort, we found that weight loss, elevated erythrocyte sedimentation rate (ESR) and higher angiopoietin-2/-1 ratios but lower matrix metalloproteinase (MMP)-3 levels identify concomitant GCA in PMR patients (Figure 1). In addition, we confirmed (1) that elevated platelet counts are characteristic of GCA but not of GCA look-alikes, and that low MMP-3 and proteinase 3 (PR3) levels may help to discriminate GCA from other diseases (Figure 1). Multiple biomarkers of inflammation were found elevated in patient and disease control groups when compared to HCs.

Conclusion:

This study, performed in two independent cohorts, consistently shows the potential of angiopoietin-2/-1 ratios and MMP-3 levels to identify GCA in patients presenting with PMR. These biomarkers may be used to select which PMR patients require further diagnostic workup. Platelet counts may be used to discriminate GCA from GCA look-alike patients.

Figure 1.

Summary of the most important and consistent findings in both cohorts. A shows the four factors that perform best in discriminating GCA/PMR patients overlap from isolated PMR patients in both cohorts. B shows the four factors that perform best in discriminate GCA patients from GCA look-alike patients in both cohorts. Cut-off values for the biomarkers are calculated by the Youden index.

References:

[1]van der Geest, KSM, Sandovici M, Brouwer E, Mackie SL. Diagnostic accuracy of symptoms, physical signs, and laboratory tests for giant cell arteritis: A systematic review and meta-analysis. JAMA internal medicine. 2020.

Disclosure of Interests:

Yannick van Sleen: None declared, Philip Therkildsen: None declared, Annemieke Boots: None declared, Berit Dalsgaard NIelsen: None declared, Kornelis van der Geest: None declared, Peter Heeringa: None declared, Minke G. Huitema: None declared, M.D. Posthumus: None declared, Maria Sandovici: None declared, Erik Toonen Employee of: Is an employee of Hycult Biotech, Jannik Zijlstra: None declared, Ellen-Margrethe Hauge: None declared, Elisabeth Brouwer: None declared

Cost-utility of an eHealth application 'Oncokompas' that supports cancer survivors in self-management: results of a randomised controlled trial

Purpose

The eHealth self-management application ‘Oncokompas’ was developed to support cancer survivors in monitoring health-related quality of life (HRQOL) and symptoms, and obtaining personalized feedback and options for supportive care. The aim of this study was to assess the cost-utility of Oncokompas compared with care as usual (CAU) among cancer survivors.

Methods

Survivors were randomly allocated to the intervention or control group. Direct (non-)medical, indirect non-medical costs, and HRQOL were measured at 3- and 6-month follow-up, using iMTA Medical Consumption and Productivity Costs and the EuroQol-5D questionnaires. Mean cumulative costs and quality-adjusted life-years (QALYs) were compared between both groups.

Results

In total, 625 survivors were randomized into intervention (n = 320) or control group (n = 305). Base case analysis showed that incremental costs from a societal perspective were − €163 (95% CI, − 665 to 326), and incremental QALYs were 0.0017 (95% CI, − 0.0121 to 0.0155) in the intervention group compared with those in the control group. The probability that, compared with CAU, Oncokompas is more effective was 60%, less costly 73%, and both more effective and less costly 47%. Sensitivity analyses showed that incremental costs vary between − €40 and €69, and incremental QALYs vary between − 0.0023 and − 0.0057.

Conclusion

Oncokompas is likely to be equally effective on utilities, and not more expensive than CAU, and will therefore contribute to sustainable cancer survivorship care in a (cost-)effective manner.

Implications for Cancer Survivors

Oncokompas seems to improve HRQOL and reduces the burden of several tumour-specific symptoms, while costs from a societal perspective are similar to CAU.

Electronic supplementary material

The online version of this article (10.1007/s11764-020-00912-9) contains supplementary material, which is available to authorized users.

Abstract P2-06-04: Breast cancer after Hodgkin lymphoma: Influence of endogenous and exogenous gonadal hormones on the radiation dose-response relationship

Background

After chest radiotherapy (RT) for Hodgkin lymphoma (HL), women experience a dose-dependent increased breast cancer (BC) risk. It is unknown whether endogenous and exogenous gonadal hormones affect the radiation dose-response relationship.

Methods

We conducted a nested case-control study among female 5-year HL survivors treated before 41 years between 1965-2000. Data were collected through medical records and questionnaires for 174 BC cases and 466 matched controls. RT charts, simulation films and mammography reports were used to estimate the radiation dose to the location of the breast tumor.

Results

The median interval between HL and BC diagnosis was 21.9 years. 98% of BC cases had received chest RT, compared to 92% of controls. We observed a linear radiation dose-response curve with an adjusted excess odd ratio (EOR) of 5.4%/Gray (95%CI:1.8%-13.37%). Women with menopause &lt;30 years (caused by high-dose procarbazine or pelvic RT) had a lower BC risk (OR:0.13, 95%CI:0.03-0.54) than women with menopause ≥50 years. BC risk increased with 7.4% for each additional year of intact ovarian function after RT (P&lt;0.001). Among women with an early menopause (&lt;45 years), the use of hormone replacement therapy (HRT) for ≥2 years did not increase BC risk (OR:0.81, 95%CI:0.30-2.21). Endogenous and exogenous hormones did not statistically significantly modify the slope of the radiation dose-response relationship.

Conclusion

HRT use did not appear to increase BC risk in female HL survivors with a therapy-induced early menopause. Moreover, there was no evidence for interaction between RT dose and years with intact ovarian function or HRT use.

Citation Format: Krul IM, Opstal - van Winden AWJ, Aleman BMP, Janus CPM, van Eggermond AM, de Bruin ML, Hauptmann M, Krol ADG, Schaapveld M, Broeks A, Kooijman KR, Fase S, Lybeert ML, Zijlstra JM, van der Maazen RWM, Kesminiene A, Diallo I, de Vathaire F, Russell NS, van Leeuwen FE. Breast cancer after Hodgkin lymphoma: Influence of endogenous and exogenous gonadal hormones on the radiation dose-response relationship [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-06-04.

(18)F-fluoride-PET for dynamic in vivo monitoring of bone formation in multiple myeloma

Background

Bone disease in multiple myeloma is characterized by reduced bone formation. The gold standard of bone formation is the mineral apposition rate (MAR), an invasive technique reflecting bone formation at a single site. We compared ¹⁸F-fluoride-PET with the MAR in myeloma patients.

Methods

Bone formation was measured before and after bortezomib treatment by determination of the MAR in iliac bone marrow biopsies and the measurement of ¹⁸F-uptake.

Results

The inter- and intra-individual variations in ¹⁸F-uptake (SUV_A50%) were pronounced as 33.50 (range 4.42 to 37.92) and 27.18 (range 4.00 to 31.18), respectively. A significant correlation between the MAR and ¹⁸F-uptake was found (r = 0.80, p = 0.017). There was a heterogeneous response after treatment varying from −2.20 to 4.53.

Conclusions

Iliac ¹⁸F-uptake was associated with the local MAR in myeloma patients. Furthermore, ¹⁸F-fluoride-PET demonstrated the heterogeneity of in vivo bone formation, enabling monitoring during treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13550-016-0197-4) contains supplementary material, which is available to authorized users.

Treatment of older patients with mantle-cell lymphoma

BACKGROUND

The long-term prognosis for older patients with mantle-cell lymphoma is poor. Chemoimmunotherapy results in low rates of complete remission, and most patients have a relapse. We investigated whether a fludarabine-containing induction regimen improved the complete-remission rate and whether maintenance therapy with rituximab prolonged remission.

METHODS

We randomly assigned patients 60 years of age or older with mantle-cell lymphoma, stage II to IV, who were not eligible for high-dose therapy to six cycles of rituximab, fludarabine, and cyclophosphamide (R-FC) every 28 days or to eight cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) every 21 days. Patients who had a response underwent a second randomization to maintenance therapy with rituximab or interferon alfa, each given until progression.

RESULTS

Of the 560 patients enrolled, 532 were included in the intention-to-treat analysis for response, and 485 in the primary analysis for response. The median age was 70 years. Although complete-remission rates were similar with R-FC and R-CHOP (40% and 34%, respectively; P=0.10), progressive disease was more frequent with R-FC (14%, vs. 5% with R-CHOP). Overall survival was significantly shorter with R-FC than with R-CHOP (4-year survival rate, 47% vs. 62%; P=0.005), and more patients in the R-FC group died during the first remission (10% vs. 4%). Hematologic toxic effects occurred more frequently in the R-FC group than in the R-CHOP group, but the frequency of grade 3 or 4 infections was balanced (17% and 14%, respectively). In 274 of the 316 patients who were randomly assigned to maintenance therapy, rituximab reduced the risk of progression or death by 45% (in remission after 4 years, 58%, vs. 29% with interferon alfa; hazard ratio for progression or death, 0.55; 95% confidence interval, 0.36 to 0.87; P=0.01). Among patients who had a response to R-CHOP, maintenance therapy with rituximab significantly improved overall survival (4-year survival rate, 87%, vs. 63% with interferon alfa; P=0.005).

CONCLUSIONS

R-CHOP induction followed by maintenance therapy with rituximab is effective for older patients with mantle-cell lymphoma. (Funded by the European Commission and others; ClinicalTrials.gov number, NCT00209209.).

[Radio-immunotherapy for B-cell non-Hodgkin lymphoma]

Radio-immunotherapy is a new treatment modality for patients with B-cell non-Hodgkin lymphoma. In radio-immunotherapy, a therapeutic radionuclide is coupled to a monoclonal antibody directed against a tumour-specific or tumour-associated antigen. Biodistribution studies and dosimetry are used in the planning of radio-immunotherapy. Clinical studies, notably in patients with indolent non-Hodgkin lymphoma, have demonstrated the clinical feasibility and efficacy of this treatment. The use of a high dose ofradio-immunotherapy in combination with (high-dose) chemotherapy and peripheral stem-cell transplantation constitutes a supplemental treatment for patients who respond insufficiently or not at all to standard therapy. The exact place of radio-immunotherapy in the treatment of patients with non-Hodgkin lymphomas is not yet clear.

An oral carcinogenicity and toxicity study of senna (Tinnevelly senna fruits) in the rat

Senna (Tinnevelly senna fruits), a known laxative derived from plants, was administered by gavage to Sprague-Dawley (Crl:CD (SD) BR) rats once daily at dose levels of 0, 25, 100 and 300 mg/kg/day for up to 104 consecutive weeks. Based upon clinical signs related to the laxation effect of senna, the highest dose (300 mg/kg/day) was considered to be a maximum tolerated dose. Sixty animals per sex were assigned to the control and dose groups. Assessments included clinical chemistry, hematology, full histology (control and high-dose groups; in addition, low and mid dose: intestinal tract, adrenals, liver, kidneys, brain and gross lesions) and toxicokinetics. The primary treatment-related clinical observation was mucoid feces seen at 300 mg/kg/day. When compared to controls, animals administered 300 mg/kg/day had slightly reduced body weights, increased water consumption and notable changes in electrolytes in serum (increases in potassium and chloride) and urine (decreases in sodium, potassium and chloride). The changes in electrolytes are most likely physiologic adaptations to the laxative effect of senna. At necropsy, dark discoloration of the kidneys was observed in animals in all treated groups. Histological changes were seen in the kidneys of animals from all treated groups and included slight to moderate tubular basophilia and tubular pigment deposits. In addition, for all treated groups, minimal to slight hyperplasia was evident in the colon and cecum. These histological changes, together with the changes seen in the evaluation of clinical chemistry and urine parameters, have been shown to be reversible in a previous 13-week rat study of senna. No treatment-related neoplastic changes were observed in any of the examined organs. Based upon these data, it is concluded that senna is not carcinogenic even after daily administration for 2 years at dosages of up to 300 mg/kg/day in Sprague-Dawley rats.

Venoruton metabolites: pharmacological activity and kinetics

Objective: This study was undertaken to further elucidate the mechanism of action of the phlebotonic drug Venoruton®, which is a standardized mixture of hydroxyethylrutosides (HR).

Methods: First, its oral absorption in rats was compared with that of hydroxyethylquercetins (HQ), which are the hydrolysed aglycones of HR. Second, the pharmacological activity of the major HR metabolites in humans, mono-3′-hydroxyethylquercetin (mono-3′HQ) and a mixture with mono-4′HQ, were further evaluated in vitro.

Results: Time to reach the maximal plasma concentration of its marker metabolite mono-4′HQ was significantly shorter after HQ than after HR administration, with an eightfold higher maximal concentration. The rapid absorption of HQ and the increased plasma levels confirm the theory that rutosides need to be hydrolysed by the intestinal microflora prior to absorption. Mono-3′HQ and, even more so, the mixture with mono-4′HQ inhibited xanthine oxidase, an enzyme responsible for the formation of reactive oxygen species, at concentrations comparable to those found in human plasma. The metabolites also inhibited the formation of superoxide radicals induced by the respiratory burst of activated HL-60 neutrophils. Both HR metabolites decreased the degree of cell death of human umbilical vein endothelial cells that were exposed to hypoxia/reoxygenation conditions, probably by scavenging destructive superoxide radicals.

Conclusions: These results demonstrated new pharmacological activities, which contribute to the understanding of the mechanisms of action of HR in chronic venous insufficiency.

Mechanical ventilation of healthy rats suppresses peripheral immune function

This study was designed to investigate the possible effect of injurious mechanical ventilation on peripheral immune function of healthy rats. Three ventilation strategies were compared: 1) low peak inspiratory pressure (PIP)/positive end-expiratory pressure (PEEP); 2) high PIP/PEEP; and 3) high PIP/zero PEEP (ZEEP). As a reference group, healthy, nonventilated, sham-operated, anaesthetised rats were used. After 4 h, rats were sacrificed and macrophage inflammatory protein (MIP)-2 levels in lung and plasma were determined. Peripheral immune function was determined by measurement of splenic natural killer (NK) activity, mitogen-induced splenocyte proliferation and in vitro cytokine production. All immune measurements in the low PIP/PEEP group did not differ from the immune measurements in the reference group. High PIP strategies, irrespective of applied PEEP, enhanced MIP-2 levels in lung and plasma. NK cell activity, mitogen-induced splenocyte proliferation and MIP-2 and interleukin (IL)-10 production significantly decreased after high PIP/PEEP ventilation. In the high PIP/ZEEP-ventilated group, the decrease in splenocyte proliferation, MIP-2 and IL-10 production and NK cell activity was more pronounced and interferon-gamma production was also significantly lower than in the low PIP/PEEP group. These data show that high positive inspiratory pressure ventilation induces an inflammatory response in the lung, whereas at the same time the peripheral immune response is downregulated. Ventilator-induced peripheral immune suppression may contribute to poor outcome in acute respiratory distress syndrome patients.

Acute renal failure due to non-Hodgkin lymphoma infiltration of the kidneys detected by ultrasonography and confirmed by positron emission tomography

Acute renal failure (ARF) as a consequence of non-Hodgkin lymphoma infiltration of the kidneys (LIK) is an uncommon complication of non-Hodgkin lymphoma. In literature, ARF due to LIK is reported in progressive disease. A case of non-oliguric acute renal failure secondary to relapse of large B cell non-Hodgkin lymphoma primarily localized in the mediastinum is reported. LIK of both kidneys was diagnosed by ultrasonography, computer tomography scan and 18-fluorodeoxyglucose positron emission tomography. No other causes for renal failure were found. The prognosis of renal involvement in relapsed non-Hodgkin lymphoma is poor, as is demonstrated by our case.

Neonatal dexamethasone treatment induces long-lasting changes in T-cell receptor vbeta repertoire in rats

Glucocorticoids are frequently administered for the prevention of chronic lung disease in infants with respiratory distress syndrome. However, neonatal treatment may have consequences for immune functioning in the long-term. Here we demonstrate that neonatal glucocorticoid treatment has long-lasting effects on mRNA expression of several Vbeta genes within the CD4 and CD8 T cell subset in rats. Changes in the peripheral T cell Vbeta repertoire may be a consequence of altered intrathymic selection events in which corticosterone plays an important role. Indeed, here we show that neonatal glucocorticoid treatment affects corticosterone production by thymic epithelial cells during neonatal life. In conclusion, changes in T cell Vbeta repertoire after neonatal glucocorticoid treatment may contribute to altered immune reactivity in later life.

Role of endogenous pro-enkephalin A-derived peptides in human T cell proliferation and monocyte IL-6 production

In this paper, we describe that met-enkephalin and/or enkephalin-containing intermediary peptides of the prohormone pro-enkephalin A are produced and secreted by human peripheral blood T cells and monocytes. The peptides are produced after stimulation with the mitogenic monoclonal antibodies anti-CD2.1/2.2 and anti-CD28. In monocytes, enkephalin synthesis was induced by stimulation with lipopolysaccharide. We demonstrate here that these immune cell-derived enkephalins play an important regulatory role in the immune response. By using an anti-sense oligonucleotide strategy we could block the production of enkephalins. Blockade of the production of met-enkephalin and enkephalin-containing intermediary peptides resulted in enhancement of the proliferative T cell response and inhibition of monocyte IL-6 secretion. In vitro reconstitution of the anti-sense treated cultures with synthetic met-enkephalin or the delta-type specific opioid receptor agonist deltorphin could reverse inhibition of monocyte IL-6 production, suggesting that endogenous enkephalins act via membrane opioid receptors. In contrast, addition of met-enkephalin or deltorphin to the anti-sense treated T cell cultures did not have any effect on T cell proliferation.

Beta 2-adrenergic activation enhances interleukin-8 production by human monocytes

Interleukin-8 (IL-8) is an important cytokine in inflammatory processes by functioning as a chemoattractant and as an activator of oxygen metabolism. In the present study we demonstrate that beta 2-adrenergic agonists potentiate the lipopolysaccharide (LPS) and IL-1 induced production of IL-8 by human monocytes. In addition, beta 2-adrenergic activation enhances IL-8 release and mRNA expression for IL-8 in the human monocytic cell line U937. beta 2-adrenergic activation of these cells also results in enhanced production of the anti-inflammatory cytokine IL-10. However, IL-10 is not involved in the regulation of IL-8 production. The effect of the beta 2-adrenergic agonist on IL-8 production is presumably mediated via increased cAMP formation, since it can be mimicked by the cAMP analogue dibutyryl-cAMP (db-cAMP). We conclude that enhancement of IL-8 production is one of the pathways via which beta 2-adrenergic agonists such as catecholamines can influence inflammatory responses.

Increased dexamethasone sensitivity of neonatal leukocytes: different mechanisms of glucocorticoid inhibition of T cell proliferation in adult and neonatal cells

Glucocorticoids (GC) are known to inhibit the proliferative response of leukocytes after mitogenic activation. Until now, the effects of GC on the immune system have been studied predominantly in adults. However, GC are frequently administered to human fetuses and newborns for the prevention and treatment of respiratory distress syndrome. The immune system of human newborns is still a functionally immature system. Therefore, we wondered whether the immaturity is also reflected by altered responses to hormonal signals such as glucocorticoids. We studied the effects of the GC dexamethasone (DEX) on the proliferation of peripheral blood mononuclear cells and T cells in vitro after stimulation with phytohemagglutinin, anti-CD3, anti-CD3/anti-CD28 or anti-CD2/anti-CD28. Our data demonstrate that neonatal cells are much more sensitive to inhibition of the proliferative response by DEX than adult cells (ED50 1 +/- 0.8 nM vs. 221 +/- 135 nM). This difference in sensitivity is not related to differences in affinity and capacity of binding of [3H] DEX. Moreover, we show that the mechanisms of GC inhibition differ between adult and neonatal cells. In adult cells, addition of interleukin (IL)-2 does not restore DEX inhibition of the proliferative response. In contrast, the proliferative response of neonatal cells can be restored completely by the addition of IL-2. These data suggest that the primary target of GC in neonatal cells is inhibition of IL-2 production. In adult cells, other mechanisms are responsible for inhibition of T cell proliferation.

Pulsed-field gel electrophoresis and radiation hybrid mapping analyses enable the ordering of eleven DNA loci in Xq22

The Xq22 region of the human X chromosome encompasses the loci of several genes and random DNA markers whose relative positions have not been determined. By a combination of PFGE mapping and the analysis of a selected panel of X chromosome radiation hybrid cell lines, we have constructed physical maps of Xq22 that order a total of 11 polymorphic and nonpolymorphic DNA markers. Ten of these probes have been linked physically into three separate clusters, spanning nearly 6 Mb of DNA in total. The DXS94, DXS147, DXS211, DXS17, and DXS87 loci are all present on a 2.7-Mb MluI fragment; PLP, DXS54, DXS24, and DXS83 are present on MluI fragments spanning over 1.6 Mb; and DXS178 is present on a 1.5-Mb MluI fragment. Mapping with additional enzymes has allowed the further ordering of these loci with respect to each other. Together with these data, analysis of a small set of radiation hybrids has suggested the following over-all order of loci within Xq22: centromere-DXS178-DXS94-DXS147-DXS211-DXS17++ +-DXS87- PLP-DXS54-DXS24-DXS83-COL4A5-telomere. The ordering of these random DNA markers, genes, and disease loci, including the genes responsible for Pelizaeus-Merzbacher disease and Alport syndrome, indicates DNA markers that could be of further use clinically for these diseases. Furthermore, this map should form a basis for the refinement of additional disease-associated loci in this region.

A genotypic mutation system measuring mutations in restriction recognition sequences

The RFLP/PCR approach (restriction fragment length polymorphism/polymerase chain reaction) to genotypic mutation analysis described here measures mutations in restriction recognition sequences. Wild-type DNA is restricted before the resistant, mutated sequences are amplified by PCR and cloned. We tested the capacity of this experimental design to isolate a few copies of a mutated sequence of the human c-Ha-ras1 gene from a large excess of wild-type DNA. For this purpose we constructed a 272 bp fragment with 2 mutations in the PvuII recognition sequence 1727-1732 and studied the rescue by RFLP/PCR of a few copies of this 'PvuII mutant standard'. Following amplification with Taq-polymerase and cloning into lambda gt10, plaques containing wild-type sequence, PvuII mutant standard or Taq-polymerase induced bp changes were quantitated by hybridization with specific oligonucleotide probes. Our results indicate that 10 PvuII mutant standard copies can be rescued from 10(8) to 10(9) wild-type sequences. Taq polymerase errors originating from unrestricted, residual wild-type DNA were sequence dependent and consisted mostly of transversions originating at G.C bp. In contrast to a doubly mutated 'standard' the capacity to rescue single bp mutations by RFLP/PCR is limited by Taq-polymerase errors. Therefore, we assessed the capacity of our protocol to isolate a G to T transversion mutation at base pair 1698 of the MspI-site 1695-1698 of the c-Ha-ras1 gene from excess wild-type ras1 DNA. We found that 100 copies of the mutated ras1 fragment could be readily rescued from 10(8) copies of wild-type DNA.

Technetium-99m carboxymethylcellulose: a newly developed fibre marker for gastric emptying studies

We report a study of technetium-99m-labelled carboxymethyl-cellulose (99mTc-CMC) as a newly developed non-digestible marker of the solid phase of gastric contents. The radiosynthesis is simple and shows a high labelling efficiency. In vitro and in vivo experiments demonstrated stability of the marker in the gastrointestinal tract during the process of gastric emptying. The gastric half-emptying time in ten healthy volunteers of both sexes was 105 +/- 17 min (mean +/- SD). This rate of gastric emptying is similar to that of non-digestible solid-phase markers such as in vivo labelled 99mTc-chicken liver or radio-iodinated cellulose. In comparison with digestible solid-phase markers such as 99mTc-labelled pancake or 99mTc-cooked egg, gastric emptying of 99mTc-CMC occurred more slowly, confirming the expected behaviour of a non-digestible solid-phase marker. We conclude that 99mTc-CMC has the advantage of a simple and rapid labelling procedure and may be useful for clinical studies of gastric emptying.

A decreased functional capacity of CD4+ T cells underlies the impaired DTH reactivity in old mice

The data presented in this paper show that the in vivo delayed-type-hypersensitivity (DTH) reaction to both H-2 and non-H-2 alloantigens declines with increasing age. It is also shown that cells generated in vitro are capable to transfer DTH to young naive syngeneic recipients. Using this in vitro system it could be demonstrated that cells from old CBA/Rij mice induced lower DTH responses than cells from young CBA/Rij mice. Depletion experiments with the effector T cell population showed that the DTH effector phase is mediated by CD4+ T cells. Lower responses in old mice were not due to increased CD8+ suppressor T cell activity, since after removal of the CD8+ T cells old CD4+ cells were still less effective in the generation of DTH effector T cells than young CD4+ cells. Addition of IL-2 containing supernatant to in vitro cultures did not improve the subsequent DTH response. From these data it can be concluded that the reduced DTH responses in old mice are not solely due to CD8+ suppressor cell activity and/or lack of IL-2, but that rather intrinsic defects of the CD4+ T cell population appear to play a major role in the impaired DTH reactivity during ageing.

Generation of high-rate ovalbumin-specific antibody-secreting cells in cultures of human peripheral blood B cells obtained from non-immunized blood donors

When human peripheral blood B cells are cultured for 6 days with the T cell-dependent peptide antigen ovalbumin (OA) in the presence of antigen-presenting cells and helper T cells, plaque-forming cells (PFC) are generated. These OA-induced PFC differ from the conventional high-rate antibody-secreting PFC formed after stimulation of B cells with recall antigens (e.g. tetanus toxoid) in that they secrete antibody at a very low level. Previous studies have shown that OA-induced PFC are B lymphocytes in an early activation state rather than cells that have differentiated into plasmablasts. The apparent arrest in the maturation of OA-induced PFC in an early activation phase can be overcome by simultaneous stimulation with interleukin 2 (IL-2) and gamma interferon (IFN-gamma). The isotype of the OA-specific antibodies secreted, however, are only of the IgM class, demonstrating that an isotype switch does not occur.

Ovalbumin-specific human B-cell activation and maturation. The absence of final maturation is due to the incapacity of ovalbumin-activated T cells to produce maturation factors

By means of a panel of monoclonal antibodies it is demonstrated that, in cultures of human peripheral blood mononuclear cells (PBMC) with the T-cell-dependent (TD) antigen ovalbumin (OA), responding B cells are activated from the resting state. The differentiation of the activated B cells to high rate-secreting plasma blasts, however, is arrested in an early activation phase, in which they can be detected as low rate-secreting plaque-forming cells. The arrest does not occur when stimulation with OA occurs in the presence of antigen-nonspecific activation and maturation factors, which are provided in the culture by the anamnestic response to the TD antigen tetanus toxoid.

Modulation of the immune response by POMC-derived peptides. I. Influence on proliferation of human lymphocytes

The POMC-derived peptides beta-endorphin and ACTH are capable of modulating an immune response in physiological concentrations. These neuropeptides can either enhance or inhibit the proliferative response of human peripheral blood lymphocytes after stimulation with the mitogen concanavalin A. The modulatory action of the peptides is not only dependent on the concentration but appears to be donor dependent. The response pattern observed is not determined by a selective affinity for certain amino acid sites on the molecules with "enhancing" or "inhibiting" activities, since fragments of beta-endorphin and ACTH also produce a differential donor-dependent response pattern.

Analysis of the antigen-induced in vitro differentiation of human peripheral blood B cells: stimulation with ovalbumin induces the transition from the resting state into the excited state

Human peripheral blood B lymphocytes, when cultured for 6 days with ovalbumin in the presence of T cells and monocytes, can differentiate into plaque-forming cells (PFC) secreting small amounts of antigen-specific IgM. Phenotype analysis using Ig-isotype and B-cell specific monoclonal antibodies revealed that the PFC precursor is a sIgM+ IgD+IgG- B lymphocyte. The PFC itself also carries the B-cell specific membrane antigens B1 and BA-1; it expresses only IgM on its surface. When apart from the antigen a Concanavalin A-induced, T-cell derived growth factor preparation was added to the cultures, we observed the disappearance of sIgM from the membrane. Furthermore, it was demonstrated by means of density gradient centrifugation that the differentiation of the PFC-precursor into a PFC is accompanied by a decrease in cellular density. Finally, it was shown using hydroxyurea as an inhibitor of DNA-synthesis, that the PFC-precursor passes several cycles of cell division during the process of differentiation into a PFC.

Antigen-induced plaque-forming cell responses in cultures of peripheral blood mononuclear cells of human neonates and infants

Human cord blood mononuclear cells (CBMC) were stimulated in vitro with a number of T cell-dependent antigens. Antigen-induced B cell activation was measured applying a plaque-forming cell assay for the detection of antigen-specific IgM-secreting B cells. With the exception of diphtheria toxoid, the antigens ovalbumin, sheep red blood cells, Helix pomatia hemocyanin, burro red blood cells, and tetanus toxoid elicited an IgM-plaque-forming cell response in cultures of CBMC to levels obtained for peripheral blood mononuclear cells (PBMC) from adult controls. However, for each antigen used, the antigen dose optimal for the induction of a response was consistently found to be a hundred to a thousand times lower than the concentration of the corresponding antigen optimal for adult PBMC. Longitudinal studies on PBMC obtained from infants between 2 and 30 months of age revealed that a shift of the antigen dose toward concentrations needed to induce plaque-forming cells in cultures of adult PBMC occurs at approximately age 8 months. Our data indicate that various antigens can be used for the in vitro analysis of antigen-specific B cell activation and regulatory T cell functions in studies concerning the ontogeny of the humoral immune response in humans.

Distinct role of neonatal and adult monocytes in the regulation of the in vitro antigen-induced plaque-forming cell response in man

Mononuclear cells from human cord blood (CBMC) are able to mount an antigen-specific IgM plaque-forming cell (PFC) response after primary in vitro stimulation with the T cell-dependent antigen ovalbumin (OA). The antigen dose-response relationship for the induction of PFC in cultures of CBMC is represented by a bell-shaped curve comparable to that found for mononuclear cells from adult peripheral blood (adult PBMC). The dose of OA optimal for the induction of a response in cultures of CBMC consistently, however, is 100-fold lower than the antigen dose optimal for adult PBMC (0.03 microgram OA/ml vs 3.0 micrograms OA/ml). Results obtained from co-culture experiments in which semiallogeneic combinations of parental/neonatal lymphocytes and monocytes were stimulated with a variable dose of OA indicate that the adherent cell (AC) plays a pivotal role in the establishment of the optimum antigen dose. From experiments using antigen-pulsed AC, it was concluded that neonatal and adult AC differ in their antigen handling capacity. In the presence of the prostaglandin synthetase inhibitor indomethacin the antigen dose-response relationship for the induction of PFC in cultures of CBMC shifts to an "adult type" of curve. From pulsing experiments it emerges that indomethacin affects the interaction between antigen and monocytes. Indomethacin causes an enhancement of the expression of HLA-DR at the surface of neonatal as well as adult AC; this can be down regulated by the addition of prostaglandin E2 (PGE2). The addition of PGE2 to cultures of adult PBMC leads to a shift of the optimal antigen dose for induction of PFC toward lower concentrations. Although higher levels of PGE2 were measured in the supernatant of cultured neonatal AC compared with adult AC, it seems unlikely that this observation can explain the distinct antigen dose-response relationship for the induction of a PFC response in cultures of CBMC.

Distinct role of neonatal and adult monocytes in the regulation of the in vitro antigen-induced plaque-forming cell response in man

Mononuclear cells from human cord blood (CBMC) are able to mount an antigen-specific IgM plaque-forming cell (PFC) response after primary in vitro stimulation with the T cell-dependent antigen ovalbumin (OA). The antigen dose-response relationship for the induction of PFC in cultures of CBMC is represented by a bell-shaped curve comparable to that found for mononuclear cells from adult peripheral blood (adult PBMC). The dose of OA optimal for the induction of a response in cultures of CBMC consistently, however, is 100-fold lower than the antigen dose optimal for adult PBMC (0.03 microgram OA/ml vs 3.0 micrograms OA/ml). Results obtained from co-culture experiments in which semiallogeneic combinations of parental/neonatal lymphocytes and monocytes were stimulated with a variable dose of OA indicate that the adherent cell (AC) plays a pivotal role in the establishment of the optimum antigen dose. From experiments using antigen-pulsed AC, it was concluded that neonatal and adult AC differ in their antigen handling capacity. In the presence of the prostaglandin synthetase inhibitor indomethacin the antigen dose-response relationship for the induction of PFC in cultures of CBMC shifts to an "adult type" of curve. From pulsing experiments it emerges that indomethacin affects the interaction between antigen and monocytes. Indomethacin causes an enhancement of the expression of HLA-DR at the surface of neonatal as well as adult AC; this can be down regulated by the addition of prostaglandin E2 (PGE2). The addition of PGE2 to cultures of adult PBMC leads to a shift of the optimal antigen dose for induction of PFC toward lower concentrations. Although higher levels of PGE2 were measured in the supernatant of cultured neonatal AC compared with adult AC, it seems unlikely that this observation can explain the distinct antigen dose-response relationship for the induction of a PFC response in cultures of CBMC.

Influence of erythrocyte contamination on the optimal phytohaemagglutinin concentration in Chinese hamster lymphocyte cultures

Lymphocyte cultures from the Chinese hamster were made with lymphocytes isolated with Ficoll-Isopaque or with Haemaccel. In some experiments the red blood cells (r.b.c.) that remained after lymphocyte isolation were lysed. Optimum phytohaemagglutinin (PHA) concentration for lymphocyte proliferation depended upon the manner in which the lymphocytes were obtained. Lower PHA concentrations were needed for optimum stimulation of lymphocytes isolated with Ficoll-Isopaque than for lymphocytes isolated with Haemaccel. Lysis of the r.b.c. remaining after isolation of lymphocytes with Haemaccel resulted in a decrease of optimum PHA concentration. The optimum PHA concentration depended strongly on r.b.c. contamination, the higher the r.b.c. contamination the higher the optimum PHA concentration. However, only part of the differences found in optimum PHA concentrations can be attributed to r.b.c. contamination.

Antigen-specific plaque-forming cell response of human cord blood lymphocytes after in vitro stimulation by T cell-dependent antigens

Mononuclear cells isolated from human cord blood (CBL) of full-term neonates were stimulated in vitro with a dose range of T cell-dependent antigens, i.e. ovalbumin or sheep erythrocytes, and tested for the capacity to mount an antigen-specific plaque-forming cell (PFC) response. Both of the antigens used induced in CBL a PFC response with the same kinetics of PFC formation and of the same magnitude as found in cultures of adult peripheral blood lymphocytes (PBL). However, optimal PFC responses in CBL were obtained at a hundredfold lower concentration of the antigens compared with the optimal antigen doses for the induction of a PFC response in adult PBL. This phenomenon was further investigated with respect to the antigen dose dependency of the activation of neonatal B cells and neonatal regulatory T cells. The induction of a PFC response in CBL at antigen concentrations that were suboptimal for adult PBL showed a correlation with the particular antigen dose requirements for the activation of B cells and T helper cells in neonates. Furthermore, the findings suggest that the decrease of the PFC response in CBL stimulated with supraoptimal doses of antigen was not caused by the induction of unresponsiveness at the B cell level or by interference of pregnancy-associated substances with the PFC response, but was rather the result of the activation of antigen-specific T suppressor cells. Neonatal T suppressor cells were activated at antigen concentrations that generated T helper activity in the adult. Thus, although neonatal B cells possess the intrinsic capacity to mature into antigen-specific PFC, the conditions for effective activation of neonatal T cells regulating the B cell response differ from those for the activation of adult regulatory T cells.

Different optimal PHA concentrations for stimulation of Chinese hamster lymphocytes in cultures supplemented with foetal calf serum or horse serum

Chinese hamster lymphocyte cultures were supplemented with foetal calf serum (FCS) or hose serum (HS). Addition of 2-mercaptoethanol (2-ME) to cultures supplemented with these sera resulted in a marked increase lymphocyte proliferation. The PHA concentrations necessary for optimal lymphocyte stimulation were much lower in cultures supplemented with HS than with FCS. Phytohaemagglutinin (PHA) concentrations optimal for stimulation of a given number of lymphocytes in cultures supplemented with FCS often gave inhibition of similar cultures supplemented with HS.

Chinese hamster lymphocyte cultures. Relationship between lymphocyte proliferation, cell concentration, culture time and culture area

Different numbers of Chinese hamster lymphocytes were cultured in microtiter plates with flat-, round- and V-bottomed wells for different culture times. The smallest number of cells could be stimulated in plates with V-bottomed wells. At least 25,000-50,000 cells and a longer culture time than for round- or V-bottomed plates were required for maximal stimulation in flat-bottomed plates. For a given well conformation the optimal day of culture is earlier with higher and later with lower cell concentrations. The optimal culture time for a given number of cells is shortest in V- and longest in flat-bottomed plates. The amount of PHA producing the highest thymidine incorporation for a given number of cells depends upon the well conformation. It decreases with lower cell concentration and increases with longer culture time.

Genetics of Chinese hamster mixed lymphocyte reactivity

Two-way and one-way mixed lymphocyte cultures (MLC) with Chinese Hamster peripheral blood lymphocytes were performed. Reduction of the culture surface and additon of 2-mercaptoethanol to the culture medium gives a marked enhancement of the reactivity of low numbers of lymphocytes in the MLC. Genetic analysis of the mixed lymphocyte reactivity (MLR) in the animals studied so far indicates that three or four different alleles are involved. However, not all phenotypes could be traced. The samples of different stocks of Chinese Hamsters in Europe and the United States did not all share the same alleles and the samples were also different as regards the relative frequency of phenotypes. For DNA inhibition in stimulating cells mitomycin C treatment is less suitable than irradiation. Skin graft survival time was longer in animals which showed no MLR than in animals with a positive MLR.

Tumor-induced changes in T cell mitogen responses in rats: suppression of spleen and blood lymphocyte responses and enhancement of thymocyte responses

Concanavalin A (Con A) and phytohemagglutinin (PHA) responses of spleen and blood lymphocytes from tumor-bearing (TB) rats were found to be markedly depressed in 4 different models employing tumors of spontaneous origin. Removal of phagocytic cells from both spleen and blood lymphocyte suspensions led to a complete restoration of the responses, indicating that the decreased responses were not due to intrinsic defects in the lymphocytes. The reduction was shown to be due to the inhibitory effect of an increase in the percentage of phagocytic cells. In addition, TB induced an atrophy of the thymus and a decrease in the number of thymic lymphocytes, mainly due to severe lymphocyte depletion in the cortex. The cells that remained in the thymus exhibited increased responsiveness to PHA and Con A as compared to thymus cells from normal rats. Similar results were found in hydrocortisone acetate-treated rats, suggesting that TB leads to a decrease in nonresponsive, cortical corticosteroid-sensitive thymocytes.

The influence of the serum/PHA ratio, microplate well shape and 2-mercaptoethanol on the stimulation of different numbers of cells in lymphocyte cultures from the chinese hamster

Conditions for microculture of Chinese hamster lymphocytes are described which allow measurement of thymidine uptake with 6000 to 1000 lymphocytes per culture. The relationship between degree of cell stimulation, PHA concentration culture surface and cell concentration is described, as well as the influence of addition of 2-mercaptoethanol to the cultures.

Short-term microcultures of lymphocytes from Chinese hamster peripheral blood

A microtechnique for the culture of Chinese Hamster lymphocytes is described using Cooke microtiter plates with 100,000 leucocytes in a culture volume of 0.1 ml and a culture time of three days. The culture media used were RPMI 1640 and Trowell T8 supplemented with 20% foetal calf serum (FCS) and 2 mu PHA. The cells were harvested with a Skatron cell culture harvester using glass fibre filters. Various technical aspects of the lymphocyte cultures from the Chinese Hamster are described. The relevance of changes in culture conditions to the variability of culture results was analysed for PHA and FCS concentrations, different culture media, cell concentration, vessel shape and culture duration.