Outbreak of Cryptosporidium hominis in northern Sweden: persisting symptoms in a 5-year follow-up

In 2010-2011, a waterborne outbreak of the parasite, Cryptosporidium hominis, affected approximately 27,000 inhabitants in the city of Östersund, Sweden. Previous research suggested that post-infectious symptoms, such as gastrointestinal symptoms and joint pain, could persist for up to 2 years after the initial infection. In this study, we investigated whether the parasite caused post-infectious sequelae for up to 5 years after the outbreak. Prospective cohort study. A randomly selected cohort of individuals residing in Östersund at the time of the outbreak was sent a postal questionnaire in 2011. Responders were sent a follow-up questionnaire in 2016 and completed items on whether they experienced a list of symptoms. We examined whether outbreak cases were more likely than non-cases to report post-infectious symptoms 5 years later. We analysed data using logistic regression and calculated odds ratios with 95% confidence intervals. The analysis included 626 individuals. Among the 262 individuals infected during the outbreak, 56.5% reported symptoms at follow-up. Compared to non-cases, outbreak cases were more likely to report watery diarrhoea, diarrhoea, swollen joints, abdominal pain, bloating, joint discomfort, acid indigestion, alternating bowel habits, joint pain, ocular pain, nausea, and fatigue at the follow-up, after adjusting for age and sex. Our findings suggested that cryptosporidiosis was mainly associated with gastrointestinal- and joint-related post-infectious symptoms for up to 5 years after the infection.

P14.09 INITIAL GLOBAL SYMPTOMS IN GLIOBLASTOMA ARE OFTEN MISINTERPRETED AND ASSOCIATED WITH SHORTER SURVIVAL

BACKGROUND

A seizure as the only symptom before diagnosing glioblastoma improves survival rate. Apart from seizures, the main presenting symptom of glioma in adults is cognitive dysfunction. The effect of generalized symptoms or loss of function on lead times and survival of glioblastoma has not been studied. Generalized symptoms include cognitive dysfunction, headache, dizziness and fatigue. Loss of function comprise paresis, sensory deficit and speech aberrations. The objective of this study was to evaluate the influence of different presenting symptoms regarding health care level, lead times and survival.

MATERIAL AND METHOD

Medical case notes regarding 189 consecutive patients with histopathologically verified glioblastoma, were reviewed for information about the date and level of care of the first medical appointment, presenting symptom/s, and date of the diagnostic radiology. The extent of surgery was noted. Data on oncologic treatment was retrieved. Summary statistics were provided for patient demographics and treatment factors. The estimates of overall survival were calculated using the Kaplan-Meier method. Survival time was calculated from the date of radiological diagnosis.

RESULTS

The majority of patients (66%) presented with generalized symptoms, which significantly reduced survival compared to not having generalized symptoms (mean survival 10.5 months vs 19.9 months, p=0.001). The most common generalized symptom was cognitive dysfunction which further reduced survival (mean survival 9.0 months, p=0.0001). Among the different cognitive aberrations, personality change and memory impairment were associated with a significantly poorer survival, (mean survival 7.9 months, p=0.015 and 8.0 months p=0.010, respectively). Disorientation also significantly reduced survival (mean survival 8.2 months p=0.001). Presenting with loss of function (58%) did not influence survival (mean survival 12.3 months). 32% of patients with an epileptic seizure as initial symptom had significantly prolonged survival compared to those not having an epileptic seizure (mean 18.9 months vs 11.0 months p=0.002). When comparing focal and secondary generalized epileptic seizures, focal epileptic seizures were more favorable. The first medical appointment was evenly distributed between primary health care and the emergency units. 8.4% of patients had multiple contacts in primary health care without being admitted to radiology or specialized care. All but one of them presented with generalized symptoms.

CONCLUSION

Glioblastoma patients presenting with generalized symptoms such as cognitive dysfunction are difficult to identify and have significantly poorer survival than other glioblastoma patients. Patients presenting with an epileptic seizure have shorter leadtime and longer survival.

Anopheles arabiensis oviposition site selection in response to habitat persistence and associated physicochemical parameters, bacteria and volatile profiles

A better understanding of the oviposition behaviour of malaria vectors might facilitate the development of new vector control tools. However, the factors that guide the aquatic habitat selection of gravid females are poorly understood. The present study explored the relative attractiveness of similar artificial ponds (0.8 m² ) aged at varying lengths prior to opening in such a way that wild Anopheles arabiensis could choose between ponds that were freshly set up, or were aged 4 or 17 days old, to lay eggs. Physicochemical parameters, bacterial profile and volatile organic compounds emitted from ponds were investigated over three experimental rounds. Fresh ponds contained on average twice as many An. arabiensis instar larvae (mean 50, 95% confidence interval (CI) = 29-85) as the ponds that had aged 4 days (mean = 24, 95% CI = 14-42) and 17 days (mean = 20, 95% CI: 12-34). Fresh ponds were associated with a significantly higher turbidity combined with higher water temperature, higher nitrite levels and a lower pH and chlorophyll level than the older ponds. Round by round analyses suggested that bacteria communities differed between age groups and also that 4-heptanone, 2-ethylhexanal and an isomer of octenal were exclusively detected from the fresh ponds. These characteristics may be useful with respect to developing attract and kill strategies for malaria vector control.

IgA antibodies against tissue transglutaminase, endomysium and gliadin in idiopathic polyneuropathy

OBJECTIVES

To study the prevalence of antibodies of IgA class against tissue transglutaminase (tTG), endomysium (EMA) and gliadin (AGA) in patients with chronic idiopathic axonal polyneuropathy (CIAP) and to characterize the patients clinically and neurophysiologically.

METHODS

Of 182 patients, 126 patients agreed to blood sampling. Sera were analysed by ELISAs detecting anti-tTG and AGA, whereas EMA was analysed by indirect immunofluorescence (IF) microscopy. Gastrointestinal symptoms were assessed by data from medical records and patient interviews.

RESULTS

Nine of 126 patients (7%) were seropositive in at least one test (five with positive anti-tTG and/or EMA and four with positive AGA only). One patient with elevated levels of all specificities had laboratory signs of malabsorption and gastrointestinal complaints with abdominal pain and diarrhoea.

CONCLUSIONS

Elevated levels of IgA-AGA were slightly more frequent in patients with CIAP (4%) compared to 2.5% in 1866 healthy blood donors. Highly specific serological markers indicative of coeliac disease (CD) (anti-tTG and EMA) were somewhat more common in our patients with CIAP (4%) than expected from normal reference values and from studies of the prevalence of CD in the general population. Even though these findings may indicate a relationship, the aetiological importance is unclear.

Abstract PD10-09: CYP2D6 and adjuvant tamoxifen: Impact on outcome in pre- but not postmenopausal breast cancer patients

Background: The therapeutic effect of tamoxifen in adjuvant treatment of hormone receptor positive breast cancer might be impaired in patients with cytochrome P450 2D6 (CYP2D6) genotypes that predispose to decreased formation of potent anti-estrogenic tamoxifen metabolites. However, previous studies have shown inconsistent findings in this regard. In light of two recent studies failing to show an impact of CYP2D6 genotype on outcome in postmenopausal patients, we hypothesized that deficient CYP2D6 might be of greater importance in premenopausal patients with high levels of circulating estrogen. We therefore aimed to study the effect of CYP2D6 activity in both pre- and postmenopausal patients who were adherent to tamoxifen treatment for at least one year.

Methods: 382 patients, from a population-based cohort of unselected breast cancer patients that were prescribed adjuvant tamoxifen for five years, constituted the base of the study. Information on menopausal status, tumor characteristics, treatment data including compliance and outcome was retrieved from medical records. Comprehensive CYP2D6 genotyping was performed and functionally translated into constitutive, metabolic activity.

Results: In patients adherent to tamoxifen for at least one year (n = 313) there was an association of reduced CYP2D6 activity (≤50% of normal) to both recurrence (p = 0.02) and breast cancer-specific mortality (p = 0.03). In a multivariable analysis including CYP2D6 activity, age at diagnosis, tumor size, lymph node status, grade, adjuvant chemotherapy and concomitant use of CYP2D6 inhibitors, CYP2D6 remained an independent predictor of recurrence (HR = 0.39, 95% CI: 0.18–0.85, p = 0.02) and breast cancer specific survival (HR = 0.33, 95% CI 0.12–0.90, p = 0.03). Gradually decreasing CYP2D6 activity paralleled increasing risk of recurrence and breast cancer related mortality. The effect of CYP2D6 derived mainly from premenopausal patients with an association to both recurrence (p = 0.01) and breast cancer specific survival (p = 0.04). There was no such association in the postmenopausal group.

Conclusion: In a prospectively collected cohort of tamoxifen-treated breast cancer patients, an association between CYP2D6 genotype and outcome was evident in patients that were adherent to tamoxifen treatment for at least a year. Importantly, this effect derived from premenopausal patients only.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-09.

Investigations and actions taken during 2011 due to the first finding of Echinococcus multilocularis in Sweden

Echinococcus multilocularis is a parasite that can cause alveolar echinococcosis disease. After the first positive finding of E. multilocularis in Sweden in 2011, a consulting group with representatives from relevant authorities was summoned. In this group, all relevant information was shared, strategies for information dissemination and any actions to be taken due to the finding of E. multilocularis were discussed and decided. The present paper describes the actions taken during 2011 and the results thereof, including surveillance in animals, risk assessment for humans to become infected and recommendations given to the public. Further discussion about whether the parasite was introduced, and if so, how, as well as possible future development of the infection in animals and humans in Sweden and future actions are included.

Support group participation during the post-operative radiotherapy period increases levels of coping resources among women with breast cancer

r Being diagnosed with breast cancer is a traumatic experience that can elevate levels of distress and cause depletion of coping resources in many of the disease's victims. This non-randomised case-control study among breast cancer patients undergoing radiotherapy indicates that participation in a support group that focuses on communication and mutual sharing between its member's has positive effects and increases levels of coping resources assessed with the Coping Resources Inventory (CRI). Results of the CRI showed a significant difference between the study group and control group in the social domain at the second occasion of measurement (P= 0.007) and in the emotional domain at the third occasion (P= 0.028). Within the study group, over time, increased levels of coping resources reached significant levels concerning the emotional domain at the second occasion (P= 0.025). Conversely, coping resources were decreased in the same domain within the control group over time, at the third occasion (P= 0.053). Additionally, anxiety and depression were assessed using the Hospital Anxiety and Depression Scale, showing no difference between the groups. This study shows that participation in a support group during post-operative radiotherapy can be socially and emotionally strengthening because of the opportunity for the patients to mutually share experiences.

Art therapy improves experienced quality of life among women undergoing treatment for breast cancer: a randomized controlled study

Women with breast cancer are naturally exposed to strain related to diagnosis and treatment, and this influences their experienced quality of life (QoL). The present paper reports the effect, with regard to QoL aspects, of an art therapy intervention among 41 women undergoing radiotherapy treatment for breast cancer. The women were randomized to an intervention group with individual art therapy sessions for 1 h/week (n = 20), or to a control group (n = 21). The WHOQOL-BREF and EORTC Quality of Life Questionnaire-BR23, were used for QoL assessment, and administrated on three measurement occasions, before the start of radiotherapy and 2 and 6 months later. The results indicate an overall improvement in QoL aspects among women in the intervention group. A significant increase in total health, total QoL, physical health and psychological health was observed in the art therapy group. A significant positive difference within the art therapy group was also seen, concerning future perspectives, body image and systemic therapy side effects. The present study provides strong support for the use of art therapy to improve QoL for women undergoing radiotherapy treatment for breast cancer.

Isolation and genotyping of Toxoplasma gondii from Ugandan chickens reveals frequent multiple infections

The genetic make-up of an infecting Toxoplasma gondii strain may be important for the outcome of infection and the risk of reactivation of chronic disease. In order to survey the distribution of different genotypes within an area, free-range chickens act as a good model species. In this study 85 chickens were used to investigate the prevalence, genotype and mouse virulence of T. gondii in Kampala, Uganda. Antibodies were detected in 40 chickens, of which 20 had MAT-titres of 1:20 or higher and were also positive by PCR. Genotyping of 5 loci (SAG1, SAG2, SAG3, BTUB and GRA6) showed that 6 strains belonged to genotype I, 8 to Type II and 1 to Type III. Five chickens had multiple infections; 3 individuals with Type I plus Type II and a further 2 harbouring Types I, II and III. Isolates were obtained from 9 chickens via bioassay in mice, 6 were Type II strains and 3 were from animals with mixed infection. This is the first set of African T. gondii strains to be genotyped at multiple loci and in addition to the 3 predominant lineages we found a small number of new polymorphisms and a high frequency of multiple infections.

Use of a virtual human performance laboratory to improve integration of mathematics and biology in sports science curricula in Sweden and the United States

New fields such as bioengineering are exploring the role of the physical sciences in traditional biological approaches to problems, with exciting results in device innovation, medicine, and research biology. The integration of mathematics, biomechanics, and material sciences into the undergraduate biology curriculum will better prepare students for these opportunities and enhance cooperation among faculty and students at the university level. We propose the study of sports science as the basis for introduction of this interdisciplinary program. This novel integrated approach will require a virtual human performance laboratory dual-hosted in Sweden and the United States. We have designed a course model that involves cooperative learning between students at Göteborg University and Stanford University, utilizes new technologies, encourages development of original research and will rely on frequent self-assessment and reflective learning. We will compare outcomes between this course and a more traditional didactic format as well as assess the effectiveness of multiple web-hosted virtual environments. We anticipate the grant will result in a network of original faculty and student research in exercise science and pedagogy as well as provide the opportunity for implementation of the model in more advance training levels and K-12 programs.

Detailed clonality analysis of relapsing precursor B acute lymphoblastic leukemia: implications for minimal residual disease detection

Genetic instability has important implications for detection of minimal residual disease (MRD) when the target is a clonal genetic marker revealed at diagnosis. A successful MRD detection approach requires a stable marker and for lymphoid leukemias clonal rearrangements of immunoglobulin (Ig) and T cell receptor (TCR) genes are commonly used. In the present study, Ig heavy chain (IgH) and TCR (gamma and delta) genes were studied in 18 consecutive, relapsing precursor-B ALL patients. At least one clonal rearrangement was found in all cases at presentation (IgH 94%, TCRgamma 39% and TCRdelta 28%). An altered rearrangement pattern between diagnosis and relapse was demonstrated in 14 patients (78%). At least one stable molecular target was found in 13 out of 18 cases (72%). Clonal differences between diagnostic and relapse samples were explained by: (1) loss of original rearrangements; (2) V(H) to DJ(H) joining; (3) V(H) gene replacement; (4) appearance of new rearrangements. In two cases with apparently new IgH gene rearrangements at relapse extended sequencing of the diagnostic samples revealed minor clonal rearrangements identical to the relapse clones. Interestingly, one patient displayed instability on both the IgH and TCR gene loci, whereas a stable Igkappa rearrangement was found at presentation and relapse. These data show that clonal diversity is common in precursor-B ALL and strongly suggest that MRD detection should include multiple gene targets to minimize false-negative samples. Even so, five of our 18 relapse cases (28%) lacked stable clonal markers and should have been unsuitable for MRD detection.

Receptor-mediated endocytosis in an apicomplexan parasite (Toxoplasma gondii)

Endocytosis mechanisms are poorly known in apicomplexan parasites. Here, we show that extracellular tachyzoites of Toxoplasma gondii bind and internalize heparin-like sulfated glycans in a specific, saturable manner. Discrete binding of the glycan occurs at the anterior third of the tachyzoite, where it is rapidly concentrated inside single tubulo vesicular compartments that become multiple with time. The compound is held for several hours intracellularly with no apparent exocytosis or acidification. Incubation in the continuous presence of fluorescein isothiocyanate-conjugated heparin enhances the binding and internalization of this ligand by live tachyzoites. Two tachyzoite surface polypeptides exhibit strong binding and specificity for heparin, making them candidate receptors. Uptake of fluid-phase endocytic tracers occurs via nonspecific pinocytosis in the same region of the parasite cell, but with much lower efficiency. These observations show that extracellular tachyzoites can acquire molecules through both receptor-specific and fluid-phase endocytic mechanisms. Understanding the physiological relevance of these processes for the extracellular and intracellular stages of T. gondii may bring about direct targeting of the parasite by drug delivery into the tachyzoites.

Secretion of the novel Trichinella protein TSJ5 by T. spiralis and T. pseudospiralis muscle larvae

The Trichinella tsJ5 gene is preferentially expressed in muscle larvae of Trichinella spiralis and encodes a novel protein. Previous observations have shown tsJ5 to be expressed at higher levels in encapsulating species than in non-encapsulating species and down-regulation of gene expression in T. pseudospiralis to be correlated with a lower protein abundance in the muscle larva of this species. In the present study we have determined the full-length cDNA sequence of the tsJ5 homologue in T. pseudospiralis (tpJ5). Antigens recognised by an anti-J5 antibody are found on the cuticular surface of both T. spiralis and T. pseudospiralis muscle larvae, as well as in the body wall muscle. We show that both the TSJ5 and TPJ5 proteins are found in the excretory/secretory fractions collected from muscle larva cultured in vitro and that despite the absence of a typical N-terminal signal sequence, secretion of pTSJ5 is mediated through the classical ER/Golgi secretory pathway.

Telomere length and telomerase activity in malignant lymphomas at diagnosis and relapse

Telomere length maintenance, in the vast majority of cases executed by telomerase, is a prerequisite for long-term proliferation. Most malignant tumours, including lymphomas, are telomerase-positive and this activity is a potential target for future therapeutic interventions since inhibition of telomerase has been shown to result in telomere shortening and cell death in vitro. One prerequisite for the suitability of anti-telomerase drugs in treating cancer is that tumours exhibit shortened telomeres compared to telomerase-positive stem cells. A scenario is envisioned where the tumour burden is reduced using conventional therapy whereafter remaining tumour cells are treated with telomerase inhibitors. In evaluating the realism of such an approach it is essential to know the effects on telomere status by traditional therapeutic regimens. We have studied the telomere lengths in 47 diagnostic lymphomas and a significant telomere shortening was observed compared to benign lymphoid tissues. In addition, telomere length and telomerase activity were studied in consecutive samples from patients with relapsing non-Hodgkin's lymphomas. Shortened, unchanged and elongated telomere lengths were observed in the relapse samples. The telomere length alterations found in the relapsing lymphomas appeared to be independent of telomerase and rather represented clonal selection random at the telomere length level. These data indicate that anti-telomerase therapy would be suitable in only a fraction of malignant lymphomas.

Clonal rearrangements in childhood and adult precursor B acute lymphoblastic leukemia: a comparative polymerase chain reaction study using multiple sets of primers

Ig heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements were investigated by polymerase chain reaction (PCR) amplification of diagnostic tumour samples from 91 patients (57 children and 34 adults, with cut-off at age 16) with precursor B acute lymphoblastic leukemia (ALL). Using primers directed to the framework regions (FR) 1, 2 and 3 of the IgH gene, clonal IgH rearrangements were observed in 82, 58 and 58%, respectively, whereas clonality was presented in 45 and 27% using primers hybridising to the TCR delta and gamma genes. A combination of all five primer sets used resulted in 96% positive cases (children 100%, adults 88%). The frequency of clonal IgH rearrangements correlated to patient age with a significantly lower fraction of positive cases in the adult group. The concomitant usage of more than one V(H) family gene was similar for childhood and adult ALL, and an over-representation of V(H)6 rearrangements was found in childhood ALL. Twenty-five out of 91 cases (27%) displayed an oligoclonal pattern for either IgH or TCR gene rearrangements (children 37%, adults 12%). A comparative analysis of samples from different compartments was performed in 23 patients, and differences between two or three compartments were observed in seven cases. Unexpectedly large, clonally appearing PCR products of 540-715 bp were found in three leukemias and sequence analysis verified their clonal nature. In summary, using multiple sets of primers clonal rearrangements of IgH and TCR genes can be detected in a very high frequency, including previously neglected large size PCR products. A common heterogeneity was demonstrated in different compartments reflecting ongoing clonal evolution, which can make detection of minimal residual disease (MRD) in ALL troublesome. Therefore, we suggest that a minimum of three targets should be used to minimise false-negative results.

Clonal evolution as judged by immunoglobulin heavy chain gene rearrangements in relapsing precursor-B acute lymphoblastic leukemia

Oligoclonality and ongoing clonal evolution are common features in patients with precursor-B (pre-B) acute lymphoblastic leukemia (ALL), as judged by immunoglobulin heavy chain (IgH) gene rearrangement analysis. These features are considered to be results of secondary rearrangements after malignant transformation or emergence of new tumor clones. In the present study we analyzed the IgH gene rearrangement status in 18 cases with relapsing pre-B ALL using variable heavy chain (V(H)) gene family specific polymerase chain reaction (PCR) amplification and single stranded conformation polymorphism (SSCP) analysis. Clonal IgH rearrangements were displayed in all leukemias but one, and altered rearrangement patterns occurred in five cases (29%), which were selected for detailed nucleotide sequence analysis. In one case, multiple subclones at diagnosis were suggested to be derived from a progenitor clone through joining of different V(H) germline gene segments to a pre-existing D-J(H) complex (V(H) to D-J(H) joining). Evidence for V(H) gene replacement with identical N-sequences at the V(H)-D junction and a common D-J(H) region was observed in one case. Diversification at the V(H)-D junction consisting of heterogeneous N-sequences were observed in one case. This molecular modification of the V(H)-D region could fit a hypothesized "open-and-shut" mechanism. Nevertheless, despite these ongoing events at least one IgH rearrangement remained unchanged throughout the disease in most patients, indicating that the immunoglobulin heavy chain locus can be a suitable marker for detection of minimal residual disease (MRD).

V(H) gene family utilization in different B-cell lymphoma subgroups

V(H) gene family specific polymerase chain reaction (PCR) amplification was performed in 87 B-cell lymphoma samples from 4 different subgroups. No apparent restriction in the VH gene usage was found in follicular lymphomas, lymphoplasmacytoid lymphomas or large B-cell lymphomas, whereas a biased VH1 utilization was shown in patients with chronic lymphocytic leukemia. Eleven of 18 chronic lymphocytic leukemia cases utilized the VH1 gene family, and nucleotide sequencing of the VH1 gene rearrangements revealed that a majority utilized the DP10 (51p1) germline gene, which has been reported to be strongly associated with autoimmune disease. No VH5 or VH6 rearrangements were amplified in the chronic lymphocytic leukemia subgroup, 2 gene families which previously have been found to be over-represented in these patients. In a high proportion (40%) of large B-cell lymphomas, VH gene family-specific PCR failed to amplify any rearrangement. Using primers hybridizing to the framework regions 2 and 3 and Southern blot analysis of the immunoglobulin heavy chain locus, clonal rearrangements were displayed in two-thirds of these PCR negative cases. However, the rearrangement status could not be elucidated in 5 of 35 patients with large B-cell lymphoma.

Immunohistochemical analysis of the proliferation associated nuclear antigen CENP-F in non-Hodgkin's lymphoma

CENP-F is a newly characterized cell cycle-associated nuclear antigen that is expressed in low amounts in G0/G1 cells and that accumulates in the nuclear matrix during S phase with a maximal expression in G2/M cells. CENP-F can be analyzed by flow cytometry and used as a proliferation marker. In the present study, therefore, we characterized the expression of CENP-F in non-Hodgkin's lymphoma by immunohistochemical techniques to detect potential dysregulation of the protein or to establish CENP-F as a reliable proliferation marker. A polyclonal rabbit antibody reacting with CENP-F was prepared and used for immunohistochemical analyses after antigen retrieval. The rabbit antibody produced immunofluorescence patterns, flow cytometric profiles, and Western blot reactivity identical to those of the human autoantibody used in earlier studies. The percentage of CENP-F-positive and Ki-67-positive cells, as well as the labeling index, S-phase time, and potential doubling time, derived from in vivo iododeoxyuridine incorporation, were evaluated in 41 non-Hodgkin's lymphomas. Aggressive lymphomas showed higher CENP-F values than did indolent cases (10.1 vs. 3.4%). The percentage of CENP-F-positive cells correlated significantly to the S-phase fraction (r(s) = 0.68), the Ki-67 index (r(s) = 0.56) and the labeling index of iododeoxyuridine (r(s) = 0.47), as well as to S-phase time and potential doubling time (r(s) = 0.34 and -0.40). A lower fraction of CENP-F-positive cells was found, compared with the Ki-67 index (4.9 vs. 9.4%), supporting previous observations that CENP-F was expressed in a fraction of actively growing cells. These correlative data indicate that CENP-F expression defines a specific subpopulation of growing cells and that no clear evidence for dysregulation was found. Accordingly, CENP-F seems to be a useful proliferation marker for formalin-fixed and paraffin-embedded material.

Low rate of somatic hypermutations characterize progressive B-cell lymphomas

Immunoglobulin heavy (IgH) chain gene rearrangements were characterized in 40 samples from 15 patients with B-cell lymphomas at different time points during tumour progression. Using polymerase chain reaction (PCR) amplification and single strand conformation polymorphism (SSCP) analysis of variable heavy (VH) chain gene segments, we found that 6 cases displayed alterations in their IgH chain rearrangements at relapse. These alterations were mainly observed in follicular or transformed lymphomas, but no association to clinical features was found. Nucleotide sequence analysis revealed a low frequency of mutations in 3 cases, whereas 1 case displayed an extensive mutation rate in a compartment with transformed morphology at relapse. The mutations observed most probably resulted from somatic hypermutations. Further, the mutations were scattered randomly over the VH gene segment and no significant bias favouring amino acid substitutions was observed in 3 cases, suggesting that the tumour cells had not been subjected to antigen-driven selection. In 1 case, however, the mutation pattern indicated that the tumour cells had been affected by an antigen selection process. In the 2 remaining cases, the original V(H)DJ(H) rearrangement could no longer be detected by VH gene family specific PCR at relapse, but using primers specific for the framework region 2 or 3 altered rearrangements were demonstrated, implying that mutations had been introduced in framework region 1. However, the majority of the tumour cell clones analysed were relatively stable during tumour progression, which make them eligible for analysis of minimal residual disease using the VH gene regions as molecular markers.

Expression of cyclin E and the cyclin-dependent kinase inhibitor p27 in malignant lymphomas-prognostic implications

Cyclin E and the cyclin-dependent kinase inhibitor p27 are two important regulators of the G1-S transition modulating the activity of cyclin-dependent kinases. Aberrations in the cell cycle control are often observed in tumors and might even be mandatory in tumor development. To investigate the importance of cell-cycle defects in malignant lymphomas we have characterized the expression of cyclin E and p27 in 105 newly diagnosed lymphomas using immunohistochemistry. A significant, inverse correlation between p27 and cyclin E expression was observed (rs = -.24, P = .02) and both proteins correlated with the S-phase fraction (rs = -.35, P < .001 and rs = . 45, P < .001, respectively). The inverse relationship between p27 expression and proliferation was abrogated in some lymphomas, suggesting that p27 downregulation can represent a genuine aberration. Survival analysis was performed in 105 patients with a median observation time of 86 months. Low p27 and high cyclin E expression were significantly associated with a poor prognosis (P = . 0001 and .03, respectively). In a multivariate Cox analysis, p27 expression, stage, serum lactate dehydrogenase level, grade, and age were independent prognostic factors, in contrast to S-phase fraction and cyclin E expression. This is the first report showing that p27 expression in malignant lymphomas has independent prognostic significance, which necessitates future studies regarding its more precise biological role in lymphoid tumorogenesis.

Alterations of the immunoglobulin heavy chain locus in progressive B-cell lymphomas

Twenty-two patients with relapsed or progressive B-cell lymphomas (BCL) were analysed for alterations in the rearrangement status in the immunoglobulin heavy (IgH) chain gene in samples obtained on different occasions during the course of the disease. The analysis was performed using Southern blot hybridization of the IgH gene and polymerase chain reaction (PCR) amplification of the VH gene families combined with single-strand conformation polymorphism (SSCP) analysis. Using Southern blot analysis, we found that all 22 lymphomas displayed clonal IgH rearrangements, and changes during tumour progression occurred in 8 cases. These alterations were mainly observed in cases with follicular or transformed lymphomas. More than one malignant (sub)clone, indicated by more than two rearranged bands, was detected in one case at diagnosis and in three cases at relapse. Outgrowth of subclones with divergent rearrangement patterns in different compartments was also observed in 2 out of 8 cases. PCR-SSCP analysis indicated that all 15 cases studied displayed clonal rearrangements and in 6 cases altered rearrangement patterns were detected in later samples. Southern blotting and PCR-SCCP analysis gave equivalent results. No association was found between time to relapse or survival time and alterations in rearrangement pattern. The present study illustrates that the neoplastic cell clones in BCL often display alterations in their IgH locus, but the significance of this feature remains to be clarified.

Expression of activation markers CD23 and CD69 in B-cell non-Hodgkin's lymphoma

The activation associated proteins CD23 and CD69 are expressed on cells of different lineages upon mitogenic stimulation. CD23 is a well characterized multifunctional protein in lymphocyte development recognized as a diagnostic marker for chronic lymphocytic leukaemia. CD69 is one of the earliest markers expressed after activation of T cells, but its function is unclear. The aim of this study was to investigate the expression of these antigens in B-cell non-Hodgkin's lymphomas (NHL) in relation to clinical behaviour. Ninety samples from 84 patients with NHL of B cell type were studied for the expression of CD23 and CD69 in CD20+ B cells by flow cytometric dual parameter analysis. In individual lymphomas the CD23 and CD69 antigens showed an "on or off" pattern with most or very few cells positive for each antigen. The CD23 antigen was expressed in 23 of 53 (43%) indolent lymphomas and in 2 of 37 (5%) aggressive cases. Most indolent lymphomas (81%) and about half the aggressive cases (53%) expressed the CD69 antigen. Thus, both markers were associated with indolent type. CD23 expression correlated with chronic lymphocytic leukaemia subtype and CD69 expression with male gender, advanced stage, newly diagnosed lymphoma and shorter survival.

[Late side-effects are common after treatment of Hodgkin's disease. Muscular atrophy following radiotherapy is a neglected risk]

As Hodgkin's disease (HD) is amenable to treatment, especially in the young, the majority of patients are long-term survivors and late treatment-related side-effects can become a clinical problem. After a retrospective review of the records of 134 patients treated for HD at Umeå during the period, 1975-90, and 15-50 years of age at diagnosis, a questionnaire on late side-effects of treatment was sent to the 110 survivors, of whom 90 per cent responded. Many patients reported late side-effects such as hypothyroidism, dryness of the mouth, cardiac and pulmonary problems, and fertility disorders. Of the 20 patients who reported pain and weakness of the neck and shoulders, 18 had undergone mantle field irradiation (i.e., of the lymph nodes of the neck, axillae and mediastinum). If shown to be equally effective, lower irradiation doses might be given in future, thus perhaps minimising long-term side-effects.

Comparative analysis of detection systems for evaluation of PCR amplified immunoglobulin heavy-chain gene rearrangements

Four different detection systems were compared for evaluation of polymerase chain reaction (PCR) amplified immunoglobulin heavy-chain gene rearrangements in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL) of B-cell lineage. In 63.0% of the fragments detected by ethidium bromide stained agarose gel electrophoresis (Agarose-EtBr) the sensitivity was insufficient to separate the specific clonal population from the background of normal B cells. Using polyacrylamide gel electrophoresis (PAGE), PAGE combined with single-strand conformation polymorphism (PAGE-SSCP) and PhastGel-SSCP (Phast-SSCP) analysis with silver staining, the resolution was improved and the majority of the inconclusive amplicons were elucidated. However, Phast-SSCP displayed a slightly higher detection level compared to PAGE and PAGE-SSCP. According to our findings PAGE-SSCP and Phast-SSCP were superior to agarose-EtBr and PAGE in detecting new emerging clones and clonal evolution.

Immunoglobulin VH gene replacements in a T-cell lymphoblastic lymphoma

We have analysed the rearrangement status of the immunoglobulin heavy (IgH) chain locus during progression of a T-cell lymphoblastic lymphoma displaying multiple IgH rearrangements as demonstrated by variable heavy (VH) gene family specific polymerase chain reaction (PCR) analysis. The tumor was found to undergo diversification at the IgH locus between diagnosis and relapse through a mechanism of VH to VHDJH replacement. In subsets of the tumor at relapse, two separate VH gene segments were found to have replaced the VH gene utilized by a VHDJH rearrangement identified at diagnosis. The observed VH gene replacement events appear to have been mediated by a heptamer sequence homologous to the heptamer of the recombination signal sequence (RSS) located internally in the VH gene segment. These results support the notion that VH replacements contribute to the diversification of immunoglobulin genes.

Flow cytometric evaluation of proliferating cell nuclear antigen expression in human hematopoietic malignancies

Cell proliferation is a strong prognostic factor in various malignancies including non-Hodgkin's lymphoma's (NHL). Several methods to evaluate tumour proliferation are available based on immunohistochemical and flow cytometric techniques, but none has been widely accepted for multicenter studies. In the present study 51 samples from patients with haematological disorders were analysed for the expression of proliferating cell nuclear antigen (PCNA) by a previously described flow cytometric approach. S-phase specific PCNA (PCNA-S) as well as growth fraction-associated PCNA (PCNA-tot) expression were evaluated. The mean value for PCNA-S was 9.0% and for PCNA-tot 17,4%. PCNA-S and PCNA-tot correlated strongly to each other (r(s) = 0.969, p < 0.001) and to the S-phase fraction determined by DNA histogram analysis (r(s) = 0.927 and 0.934 respectively, p < 0.001). In 23 cases with NHL in vivo iododeoxyuridine (IdUrd) labelling was performed to assess the labelling index (IdUrd-LI, i.e. S-phase fraction), S-phase duration time (Ts) and potential tumour doubling time (Tpot). IdUrd-Li correlated significantly to both PCNA-S and PCNA-tot (r(s) = 0.704 and 0.622 respectively, p < 0.001 and 0.02). In conclusion, especially the PCNA-S seemed to be a candidate for future larger studies of proliferation related aspects of haematological malignancies.

Cell kinetic analysis of non-Hodgkin's lymphomas using in vivo iododeoxyuridine incorporation and flow cytometry

The aim of this study was to analyse dynamic cell proliferation parameters in non-Hodgkin's lymphomas. Sixty-one patients with newly diagnosed or with recurrent disease were given iododeoxyuridine (IdUrd) intravenously near 4 h prior to tumour biopsy. After staining with an IdUrd reactive antibody and propidium iodide, S-phase fraction (SPF), labelling index (LI), S-phase duration time (Ts) and potential tumour doubling time (Tpot) were determined by flow cytometry. Thirty-eight samples, 15 low grade (LGM) and 23 high grade (HGM) malignant lymphomas, were possible to evaluate. Twenty-three cases were excluded due to aneuploidy, insufficient amount of material or technical problems. Tpot values varied between 0.8-32.9 days (mean 7.0 days). HGM lymphomas had shorter mean Tpot times than LGM lymphomas (4.8 versus 10.4 days, p = 0.05). For Ts the range was 4.2-20.1 h (mean 9.1 h), and a difference between the two histological groups was demonstrated with a longer mean Ts for HGM compared with LGM cases (10.0 versus 7.8 h, p = 0.04). Tpot showed a negative correlation with SPF (P = 0.003), and Ts demonstrated a positive correlation to SPF (p = 0.02). The clinical significance of the dynamic cell proliferation parameters studied remains to be clarified, but the interrelationships between Ts/SPF and Ts/morphologic subtype might be factors of interest for future prognostic studies in malignant lymphomas.

Simultaneous immunoglobulin/T-cell receptor gene rearrangements and multiclonality in childhood acute lymphoblastic leukemia

Twenty-five children less than 16 years of age with acute lymphoblastic leukemia (ALL) were investigated with immunologic, cytogenetic and molecular genetic techniques at diagnosis. All pre-B-cell ALL showed clonal rearrangements in the immunoglobulin heavy chain gene (JH and/or C mu). A very high proportion of the pre-B-cell leukemias (17 of 23 cases) also showed clonal rearrangements in T-cell receptor genes (T gamma and/or T beta). The two T-cell leukemias exhibited clonal T-cell receptor gene rearrangements and in one JH and kappa light chain rearrangements also. The T-cell receptor gene rearrangements found in pre-B-cell leukemias appeared to occur randomly with respect to the T beta and T gamma genes. A significant proportion of the leukemias (at least 24%) seemed to harbor more than one malignant (sub)clone at diagnosis. Cytogenetic studies revealed a clonal abnormality in 10 cases. Only 2 showed hyperdiploidy (> 50 chromosomes). The only correlation between cytogenetic findings and rearrangement patterns was extra bands corresponding to a possible trisomy of chromosome 14. Our data indicate, in line with previous studies, that childhood ALL has complex rearrangement patterns not useful for lineage sub-classification. For this purpose immunophenotyping appears to be superior. However, molecular analysis can reveal the presence of more than one clone not detected by immunophenotyping or karyotyping, and distribution of clones in different compartments. In this study no correlation with clinical outcome was observed.

Multiclonality and altered RFLP patterns for immunoglobulin heavy-chain and T-cell receptor genes in relapsing lymphomas

BACKGROUND

Alteration of morphological appearance as well as of clinical behaviour is common in relapsing non-Hodgkin's lymphomas. The aim of this study was to investigate the stability of the genes encoding the immunoglobulin heavy-chain and the T-cell receptor during the course of the disease in relapsing non-Hodgkin's lymphomas.

MATERIAL AND METHODS

Nineteen patients with relapsed or progressive non-Hodgkin's lymphomas were analysed with respect to alterations of the restriction fragment length polymorphism (RFLP) pattern for Ig heavy chain (IgH) using probes for the C mu and J regions and for T-cell receptor (T-beta, T-gamma chain) genes. DNA was extracted from tumour material taken at different occasions during the course of the disease.

RESULTS

All 19 cases showed clonal rearrangements of the IgH locus, and 2 cases showed simultaneous rearrangement of the genes coding for the T-cell receptors. Three or more rearranged bands, indicating more than one malignant clone, were detected in 1 case at the time of the diagnosis and in 5/19 (26%) cases in DNA from samples taken at relapse, all 6 cases showing discordant or transformed morphology. Altogether, in 11 out of 19 cases (58%), changes of the IgH rearrangement pattern could be visualized by RFLP. In all these cases except one, the new RFLP pattern included at least one rearranged band from the pattern of the first taken sample. In one case a clonal T-gamma receptor gene rearrangement was detected in a diagnostic sample but not in a sample taken at relapse. In 4 out of 6 cases with transformed lymphomas, clonal changes were observed at time of transformation. Evolution of clones with different RFLP patterns in different compartments were observed in 1 out of 6 studied cases.

CONCLUSIONS

The present study illustrates that non-Hodgkin's lymphomas are unstable in their IgH genome. The observations of clonal evolution, multiclonality, and different clones in different compartments offer an explanation to the troublesome situation when treating relapsed lymphomas.

Prognostic significance of serum lactic dehydrogenase levels and fraction of S-phase cells in non-Hodgkin lymphomas

Sixty-four untreated patients with non-Hodgkin lymphomas (NHL) were analyzed with respect to fraction of S-phase cells in tumor material and serum lactic dehydrogenase (LD) levels. A significant correlation between the two variables was found in the low-grade (LGM) (r = 0.44, p < 0.01), but not in the high-grade (HGM) lymphomas. Shorter survival times were found for patients with tumors showing a high fraction of S-phase cells (> 4%) (p < 0.001) as well as for patients with elevated LD values (> or = 7.5 mukat/l) (p < 0.001). A multivariate analysis showed clinical stage (p < 0.001), S-phase fraction (p = 0.002) and age (p = 0.002) to be independent prognostic factors. For serum LD a borderline value (p = 0.05) was found, whereas morphology and B-symptoms were non-significant. LD level, but not fraction of S-phase cells, added prognostic information for LGM lymphomas (p < 0.001). For HGM lymphomas, the clinical stage was the strongest factor for prediction of prognosis. We conclude that the fraction of S-phase cells describes the biological behavior in a more reliable way than morphology (HGM vs LGM) and better identifies lymphomas with poor or good prognosis. The strong additional prognostic information obtained by serum LD within LGM lymphomas is assumed to be due to an association with the tumor burden.

Ig-gene and T-cell receptor gene rearrangements in a secondary, mono-histiocytic malignancy

In 1984, a 21-year-old male was diagnosed with an acute lymphoblastic leukemia of pre-B cell type. Treatment with chemotherapy, including alkylating agents and prophylactic radiotherapy to the central nervous system, induced a complete remission. In June 1990, a biopsy from a supraclavicular node revealed a malignancy of mono-histiocytic type with erythrophagocytosis. Soon thereafter bone marrow involvement was found. No remission was achieved and the patient died in December 1990. DNA from bone marrow and lymph node obtained 1990 showed clonal rearrangements of both the immunoglobulin heavy-chain gene and the T-cell receptor gamma chain gene. This unusual case illustrates a typical secondary malignancy proven to be separate from the primary neoplasm judged by morphological appearance, immunophenotype and cytogenetic constitution. Coexistent clonal rearrangements of immunoglobulin and T-cell receptor genes have been reported in acute non-lymphoblastic leukemias and notably in cases expressing TdT, interpreted as a predominant lymphoid commitment of the tumor cells. In the present case, however, the malignant cells had a differentiated phenotype and showed erythrophagocytosis, indicating a more mature mono-histiocytic cell type. However, also CD3 expression was found by immunohistochemistry of frozen sections which might indicate a biphenotypic malignancy.

'Aggressive' low grade lymphocytic lymphomas can be identified by flow cytometric S-phase determinations

Forty-five patients with low grade non-Hodgkin's lymphomas were studied with respect to the fraction of S-phase cells in fresh tumour material by flow cytometric analysis. Patients with stage I lymphomas were treated with radiotherapy, patients with stage II-IV lymphomas with Prednimustine (Sterecyt). Patients with lymphocytic lymphomas of CLL type were only treated if they had symptoms. Median S-phase fraction in the samples was 2.0 per cent. A significantly shorter survival was found for patients with lymphocytic lymphomas with S-phase fractions > 2.0 per cent compared with cases showing lower S-phase fractions. No significant difference in survival was found in the subgroups of immunocytic or follicular and follicular/diffuse centroblastic/centrocytic lymphomas. In a Cox multivariate analysis, in which also age, constitutional symptoms, stage and morphology were included, the fraction of S-phase cells was found to be a statistically significant, prognostic parameter for low grade lymphomas, mainly due to the result in the subgroup of lymphocytic lymphomas.

Fraction of S-phase cells in blood mononuclear cells in non-Hodgkin's lymphomas--correlation with clinical features and prognosis

A consecutive material of 111 untreated patients with non-Hodgkin's lymphoma was studied with respect to fraction of S-phase cells in blood mononuclear cells in relation to presence of monoclonal B cells in blood (MBCB). Fraction of S-phase cells was determined by flow cytometry and estimation of MBCB was performed by kappa:lambda analysis. The fraction of S-phase cells was significantly higher (p less than 0.001) in MBCB-positive cases (median 1.2%) than in the MBCB-negative (median 0.7%). MBCB-positive patients with S-phase values greater than or equal to 1.5% had a less favourable prognosis compared to those with less than 1.5% cells in S-phase (p = 0.01). In a Cox multiparameter analysis, advanced clinical stage, high-grade morphology and high fraction of S-phase cells in blood in MBCB-positive cases were independent, statistically significant, negative prognostic indicators. The results indicate that an elevated S-phase value in blood in non-Hodgkin's lymphoma constitutes a negative prognostic factor, probably reflecting proliferating tumour cells in blood.

Immunoglobulin heavy-chain gene rearrangement in peripheral blood mononuclear cells in non-Hodgkin's lymphomas--correlation with kappa:lambda analysis and clinical features

41 patients with non-Hodgkin's lymphomas were analysed to determine occurrence of B-cell monoclonality in peripheral blood mononuclear cells using two different methods: determination of kappa:lambda ratio by light microscopic immunofluorescence, and heavy-chain gene rearrangement by DNA-technique. In 21 patients (51%) clonal heavy-chain rearrangement was found in blood, whilst 18 of the patients (44%) showed and abnormal kappa:lambda ratio. Discordant results between the methods were observed in 5 cases. Clones with gene rearrangements suggesting blood involvement were found in 16/25 (64%) patients with low grade lymphomas, in 5/16 (31%) patients with high grade lymphoma, in 17/21 (81%) patients with bone marrow involvement, in 20/27 (74%) of stage III-IV lymphomas and in all of the 14 patients with a high lymphocyte count (greater than or equal to 5.0 X 10(9]. The conclusion was that clonal analysis by the DNA-technique is a more sensitive method than the kappa:lambda determination using immunofluorescence. Even though the method is time-consuming, it could prove to be valuable in selected cases.

Monoclonal B-cells in blood in non-Hodgkin lymphoma. Correlation with clinical features and prognoses

Presence of monoclonal B-cells in peripheral blood (MBCB) was studied in 132 previously untreated patients with non-Hodgkin lymphoma classified according to the Kiel classification. Detection of B-cells was performed by immunofluorescence microscopy, using antibodies against immunoglobulin light chains. Thirty-six patients (27%) were found to have MBCB. In the subgroup of low grade lymphomas 25/75 (33%) and in high grade lymphomas, 11/57 (19%) had MBCB. Presence of MBCB was correlated to clinical stage and 81% of the patients with MBCB were in stage IV. Twenty-two out of 36 (61%) patients with MBCB had normal lymphocyte counts (less than 5.0 X 10(9]. MBCB indicated a less favourable prognosis, mainly due to the close association with stage IV. It was concluded that studies of MBCB by this simple method are useful in detecting 'subclinical' blood involvement and valuable in the initial staging procedure as well as in the follow-up of the patients.

A single cell assay for the study of gamma-interferon formation in leprosy patients

The number of gamma-interferon producing cells in the peripheral blood of leprosy (LL and BT) patients and controls was studied by the reversed protein A plaque assay before and after exposure in vitro to Mycobacterium leprae bacilli and Epstein-Barr virus (EBV). The level of spontaneous gamma-interferon production was significantly higher in BT patients compared to LL patients and controls. Mycobacterium leprae induced a specific gamma-interferon response in lymphocytes from BT patients and from healthy contacts whereas in LL patients and non-exposed controls the response was low or non-existing. There were no significant differences in the gamma-interferon response to EBV between the above groups.

Non-Hodgkin lymphoma. Multivariate analysis of prognostic factors including fraction of S-phase cells

In a material of 80 patients with non-Hodgkin lymphoma a multivariate analysis was carried out taking the following variables into account: Age, clinical stage, B-symptoms, morphologic diagnosis and fraction of S-phase cells in the tumour determined by flow cytometry. Clinical stage, proportion of cells in the S-phase, and age of the patient were significant independent prognostic factors. Morphologic malignancy grade and B-symptoms were not significant parameters in this analysis. It was concluded that DNA analysis with determination of the fraction of S-phase cells is a valuable complement to morphology in the evaluation of patients with non-Hodgkin lymphoma. In combination with the clinical stage it gives very good discrimination into groups with different prognoses.

Prognostic significance of DNA-analysis by flow cytometry in non-Hodgkin's lymphoma

DNA analysis by flow cytometry was performed on lymph node cells obtained from 65 untreated patients with non-Hodgkin's lymphoma. According to the Kiel classification 41 cases were of low grade malignancy and 24 cases belonged to the high grade malignancy group. 47 out of 61 evaluable cases were diploid/near-diploid, 12 were aneuploid and 2 cases showed polyploidy. No difference in survival was found between diploid/near-diploid and aneuploid cases. The percentage of S-phase cells was found to be a valuable prognostic parameter. Using a cut point at 4 per cent S-phase cells between low and high S-phase lymphomas a highly significant difference in survival was demonstrated (p = 0.0004). The actuarial survival up to 3 years was about 77 per cent for lymphomas with less than 4 per cent S-phase cells to be compared with 20 per cent for patients with high S-phase (greater than or equal to 4 per cent) lymphomas. Subdivision according to the percentage of S-phase cells seemed to be a better prognostic predictor than morphologic subclassification.

Monoclonal B cells in peripheral blood in non-Hodgkin's lymphoma. Correlation with clinical features and DNA content

Peripheral blood from 69 patients with non-Hodgkin's lymphoma was examined with respect to B and T cell markers. Evidence for monoclonal B cell was found in 29 cases, 8 of 'high grade' and 21 of 'low grade' malignancy according to the Kiel classification. 17 out of the 29 patients had a normal lymphocyte count. Using conventional staging methods 4 cases of the 29 were in stages II and III, all others in stage IV. The proportion of S-phase cells in peripheral blood, determined by flow cytometry, was found to be elevated in cases with a monoclonal cell population. It is concluded that surface marker analysis of blood cells may be valuable as a diagnostic tool, as an indicator of prognosis and perhaps for the staging procedure of malignant lymphomas.

Cell-mediated immune response to guinea pig and bovine basic proteins of myelin in Lewis and PVG rats and their hybrids

The in vitro cell-mediated immune response of rat lymph node cells (LNC) to guinea pig and bovine encephalitogenic protein (EP) has been studied with a LNC transformation test. LNC were obtained from either Lewis, PVG, or F1 (Lewis x PVG) rats 28 days after challenge with guinea pig or bovine EP in Freund's complete adjuvant (FCA) of different mycobacterium content. No differences between the strains or their hybrids in LNC response could be shown if stimulated with sensitizing EP, despite the great differences in capacity for disease development in those animals. Nor did a fivefold lowering of the amount of mycobacterium content in FCA, when guinea pig EP was used at challenge, lessen the in vitro response, although this reduces the disease development. Sensitization with guinea pig EP causes an in vitro cross-reactivity to bovine EP and the reciprocal cross-reactivity probably also exists. In rabbits, this cross-reactivity in both directions was clear-cut. LNC from Lewis rats challenged with guinea pig EP in FAC, with the higher amount of mycobacterium, showed in vitro responses to tested peptides of this EP; the amino acid sequences of these were: 1-42, 43-88, 89-169, and HNB-89-169 (89-169 blocked at the tryptophan-residue by hydroxynitrobenzylation).

Susceptibility to experimental allergic encephalomyelitis in two strains of rats and their hybrids

Lewis and PVG strains of rats and their F1-hybrids were challenged with guinea-pig or bovine encephalitogenic protein (EP) in Freund's complete adjuvant (FCA) to produce experimental allergic encephalomyelitis (EAE). The Lewis and F1-rats were also challenged with guinea-pig EP in FCA with a fivefold lower concentration of Mycobacterium butyricum. Data are presented concerning clinical signs and histological changes of EAE showing an intermediate position of susceptibility to EAE for the F1-hybrids compared to the parental strains. The findings are discussed in relation to the mode of inheritance of susceptibility to EAE. Among rats immunized with bovine encephalitogenic protein in FCA a weak activity was registered; this was difficult to evaluate, as it could be an effect of FCA only.

A quantitative study of encephalitogenic protein and peptides in guinea pigs

The encephalitogenic activity of bovine encephalitogenic protein (EP) at at doses from 1 to 33.5 microgram was studied in guinea-pigs. Anencephalitogenicity can be demonstrated at a dose of 1 microgram of EP when given with Freund's complete adjuvant. An increase in the dose of EP results in an increase in encephalitogenicity. Data from a previous paper (Lindh and Bergstrand 1975) supplemented with new data on the encephalitogenic capacity of peptide 89--169 were compared concerning the incidence and strength of experimental allergic encephalomyelitis (EAE) to determine the relative contribution of the various parts of EP to the encephalitogenic properties of the total molecule. Peptide 89--169 shows the same degree of encephalitogenicity as EP, but when the tryptophan residue is blocked (HNB-89-169) the encephalitogenicity is reduced to approx. 15% of the initial amount. Peptide 43--115, tyr (modified at the tyrosine residue 67) appears to have an encephalitogenicity of rather less than 10% of the intact EP molecule, whereas peptide 1--42, if active at all, has an encephalitogenicity of approx. 1% of the total EP molecule. The findings are discussed in the light of a possible cross-reactivity between different determinants of EP.

Disease-inducing activity of different parts of bovine encephalitogenic protein in guinea-pigs

The encephalitogenic activity of different parts of bovine encephalitogenic protein (BEP) has been tested in guinea-pigs, mainly at a dose equimolar to 32 mug of intact protein. A high activity was found with complete protein and with region 89-169; both peptide 43-115, tyr (modified at the tyrosine residue 67) and HNB-89-169 (modified at the tryptophan residue 115) showed a moderate but clear-cut activity, whereas that of peptide 1-42 was very faint. No qualitative differences in the disease induced by the different peptides could be found; in only one animal out of 139 were clinical signs observed without evidence of histological disease. Slight histological changes, similar to those seen at EAE, were found in four out of 19 animals injected with Freund's complete adjuvant only.