Angela Gause

B lymphocyte maturation in Wegener’s granulomatosis: a comparative analysis of VH genes from endonasal lesions

Background: Anti-neutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) are highly specific for Wegener’s granulomatosis (WG). Evidence for a pivotal role of PR3-ANCA in the induction of vasculitis has been demonstrated. B cell clusters have been observed within endonasal biopsy specimens. Objectives: To determine whether B cell selection and maturation take place in granulomatous lesions of WG. Methods: Granulomatous lesions and the immunoglobulin (VH) gene repertoire from nasal tissue of six WG patients—two active and two smouldering localised WG (ANCA negative, restricted to respiratory tract), plus one active and one smouldering PR3-ANCA positive generalised WG—were characterised by immunohistochemistry, polymerase chain reaction, cloning, DNA sequencing and database comparison. Results: B lymphocyte-rich, follicle-like areas were observed proximal to PR3 positive cells and plasma cells in granulomatous lesions; 184 VH genes from these granulomatous lesions were compared with 84 VH genes from peripheral blood of a healthy donor. The mutational pattern of VH genes from active WG resembled memory B cells. Structural homologies of VH genes from granulomatous lesions to PR3-ANCA encoding genes were detected. Significantly more genes (55%, 45%, and 53%, respectively) from active WG compared with the healthy repertoire carried mutations to negatively charged amino acids within the binding site coding regions, favouring affinity to the positively charged PR3. Conclusions: Selection and affinity maturation of potentially PR3-ANCA producing autoreactive B cells may start in granulomatous lesions, thereby contributing to disease progression from ANCA negative localised to PR3-ANCA positive generalised WG.

B cells of chronic lymphatic leukemia express V genes in unmutated form.

In order to investigate whether the leukemic B cells in B-CLL express immunoglobulin genes in mutated or unmutated form, independent cDNA clones of one patient with B-CLL expressing heavy and light chain V region genes were sequenced. The sequences of both the VH and V kappa clones were identical. The V genes could be assigned to known germline V genes. No somatic mutations were found. At the V kappa-J kappa border there is an insertion of N-sequences which are only rarely found in immunoglobulin light chain genes. Our study confirms other published data on V gene expression in B-CLL in that the surface immunoglobulins in these tumors are unmutated.

LACK OF EVIDENCE FOR A PATHOGENIC ROLE OF CHLAMYDIA PNEUMONIAE AND CYTOMEGALOVIRUS INFECTION IN CORONARY ATHEROMA FORMATION

Atherosclerotic cardiovascular disease is generally accepted to be the result of metabolic disturbances. However, recent studies have suggested an infectious agent, especially Chlamydia pneumoniae or cytomegalovirus, to be involved in the pathogenesis of atherosclerosis. Atherosclerotic plaque specimens obtained from patients with coronary disease either by balloon dilatation catheter (13 cases) or atherectomy (16 patients) were examined for the presence of C. pneumoniae and cytomegalovirus. Using two primer pairs for C. pneumoniae, two primer pairs for the identification of unknown bacteria and primer pairs for the detection of immediate early gene E2 and the late genomic region of cytomegalovirus, we were unable to detect the suspected agents. The absence of C. pneumoniae, other bacteria and CMV in coronary atheromas is against the hypothesis of a pathogenetic role of these agents in coronary atheroma formation in the patients studied.

Immunological and clinical follow up of hepatitis C virus associated cryoglobulinaemic vasculitis

OBJECTIVE To study immunological markers and compare these markers with standard measures for the clinical and immunological follow up of vasculitis activity in hepatitis C virus (HCV) associated cryoglobulinaemic vasculitis (CV). METHODS Serial serum samples from eight patients with newly diagnosed HCV associated CV were followed during interferon α treatment induced remission of the CV. Vasculitis activity and disease extent were evaluated with the Birmingham vasculitis activity score (BVAS) and disease extent index (DEI). Cryoglobulinaemia, complement levels (C3c, C4, and CH50), rheumatoid factor (RF), autoantibodies such as antinuclear antibodies, soluble interleukin 2 receptor (sIL2r), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble CD30 (sCD30) were determined. RESULTS All patients achieved either complete or partial remission of their CV during interferon α treatment. There was a significant reduction in vasculitis activity and disease extent (BVAS, DEI), cryoglobulinaemia, RF, sIL2r, sICAM-1, and sCD30. Complement C3c levels increased significantly during this period. Erythrocyte sedimentation rate and levels of complement C4 and CH50 did not change significantly. Both clinical measures (BVAS and DEI) correlated significantly only with C3c and sCD30. CONCLUSIONS Although this study was of only a small group of patients, it shows that BVAS and DEI as clinical measures and C3c and sCD30 as immunological markers may be useful in the follow up of disease activity of HCV associated CV. The data indicate that activity of the humoral (cryoglobulinaemia, RF, autoantibodies) and cellular (sIL2r, sICAM-1, sCD30) immune response and endothelial damage (sICAM-1) are found in HCV associated CV.

Detection of Epstein-Barr Virus DNA in Hodgkin- and Reed-Sternberg-Cells by Single Cell PCR

The Epstein-Barr virus (EBV) can be detected in the majority of lymph nodes involved by Hodgkins lymphoma using the highly sensitive polymerase chain reaction (PCR). However, the rate of EBV-DNA detection by in-situ hybridisation, which allows allocation of EBV to a defined cell population, i.e. the neoplastic H&RS-cells, is lower. In an attempt to combine the advantages of the high sensitivity of the PCR and the possibility of cellular allocation by in-situ hybridisation, we established a single-cell PCR of Hodgkin- and Reed-Sternberg (H&RS)-cells isolated by micromanipulation from biopsy tissues. We amplified EBV sequences from the BamW-region by single-cell PCR. Using this method we were able to detect EBV-DNA in the H&RS-cells from 4 of 6 patients. In EBV positive cases all H&RS-cells of a given patient were positive, proving the high sensitivity and reproducibility of the method. Other cells in the biopsy tissue involved by EBV-positive H&RS-cells were shown to be negative. This indicates that EBV may have a role in the pathogenesis of many but not all cases of Hodgkins disease.

The B lymphocyte in rheumatoid arthritis : Recirculation of B lymphocytes between different joints and blood

In order to search for further evidence for a pathogenetic role of recirculating, antigen-driven B cell clones in rheumatoid arthritis (RA) rearranged VH genes were analysed for clonal relationship and somatic mutations from synovial tissue and peripheral blood of a patient with RA undergoing synovectomy of several finger joints. DNA was prepared from the synovial tissue of two finger joints and blood. PCR for the different VH families was performed with one specific oligonucleotide for each VH family and a mixture of JH-specific oligonucleotides. The PCR products were separated on a high resolution acrylamide gel differentiating one base pair difference of length. Transfer of the products onto a nylon membrane and hybridization with an oligonucleotide specific for the FR3 region revealed a polyclonal representation of rearranged VH1, VH3, VH4 and VH5 genes. The VH6 family, which is encoded by a single germline gene, was represented by few distinct bands, with some bands of identical height for both joints and blood. DNA from these bands of interest was eluted, reamplified by PCR, cloned and sequenced. Sequence analysis of 27 independent bacterial colonies allowed distribution of the different VH genes to seven B cell clones (A-G). Members of clone A were found in both joints and blood, clones B and C in one joint and blood, clone D in both joints, and clones E, F and G only in one joint. The VH regions were somatically mutated with characteristic patterns for the different clones. In conclusion, our findings confirm the systemic character of RA, because they show that not only expansion and affinity maturation of B cells occur in synovial membranes but antigen-specific B cells recirculate between different joints and blood.

Immunoglobulin heavy and light chain gene sequences of a human CD5 positive immunocytoma and sequences of four novel VHIII germline genes

To analyse the V genes expressed by an IgM lambda CD5-positive immunocytoma heavy and light chain V region genes were cloned and sequenced. The heavy chain is composed of a previously undescribed VHIII gene joined to an unknown D gene and to JH4. The light chain V region is composed of a V lambda II gene rearranged to J lambda 1. In an attempt to clone the germline counterpart of the VHIII gene expressed in the immunocytoma PCR amplifications of genomic DNA were carried out and four previously unknown VHIII genes were identified. As several independent clones for the heavy and light chain V region genes were sequenced the rate of somatic mutation of the V genes was calculated to be below 2 x 10(-5)/bp/cell division.

The Clinical Significance of Cytokines and Soluble Forms of Membrane-Derived Activation Antigens in the Serum of Patients with Hodgkin's Disease

In a search for specific serum markers with prognostic impact in Hodgkins Disease (HD), we evaluated the clinical significance of several cytokines (IL-1 beta, IL-2, IL-3, IL-6, G-CSF, GM-CSF, TNF-alpha) and soluble forms of membrane-derived antigens (sCD4, sCD8, sCD23, sCD25, sCD30) in the serum of patients with untreated HD. Elevations of three groups of serum factors were observed: Firstly, elevations of the hematopoietic cytokines GM-CSF (detected in 39%), IL-6 (57%) and IL-3 (13%), which occurred simultaneously in the majority of the cases; secondly, simultaneous elevations of the inflammatory cytokines TNF-alpha and IL-1 beta (detected in 7%); and finally, elevations of membrane-derived activation antigens sCD8, sCD25, and sCD30. While the cytokine levels did not correlate with other obvious parameters, the membrane-derived activation antigens sCD8, sCD25 and sCD30 were associated with a poor prognosis. Only sCD30 correlated with disease activity and holds promise for the follow-up of patients in remission. Further investigations of these parameters at the cellular level might help to elucidate the enigmatic biology of HD.

Impaired Antibody Levels to Tetanus Toxoid and Pneumococcal Polysaccharides in Acute Leukemias

Antibody levels to the protein antigen tetanus toxoid (TTx) and the carbohydrate antigens pneumococcal capsular polysaccharides (PCP) were studied by enzyme immunoassay in 14 patients with acute lymphocytic leukemia (ALL) and 32 patients with acute non lymphocytic leukemia (ANLL) before and three weeks after initiation of chemotherapy. The antibody levels to TTx were significantly lower in ALL patients than in controls. This was associated with elevated levels of sCD8 (soluble CD8) in the serum of 12 out of the 14 ALL patients. Patients with ANLL had normal antibody levels before chemotherapy. After chemotherapy ANLL patients with septic complications had a reduced increase of antibody titers to TTx than patients without sepsis. The average antibody titers to PCP decreased in patients with sepsis, while they increased slightly in patients without sepsis. We conclude that in contrast to ANLL patients ALL patients have preexisting decreased antibody levels to thymus dependent protein antigens, while antibody levels to thymus independent carbohydrate antigens are normal in both types of leukemias.

Single Cell PCR at the DNA and RNA Level: A Novel Approach to the Study of Hodgkin’s Disease

Elucidation of the cellular origin of the Hodgkin and Reed-Sternberg cells (H-RS) cells, the tumour cells of Hodgkin’s disease (HD), is made difficult by the fact that these cells represent only a small minority of the cellular infiltrate in tissues affected by HD. Neither the study of cell lines nor the study of DNA or RNA extracted from HD-lymph nodes has been able to conclusively solve some of the most interesting questions, e.g., the questions of origin and clonality of the H-RS cells, the role of viruses in the pathogenesis of HD and the role of soluble and cell-bound signals in the maintenance of the malignant phenotype.