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.