Immunoglobulin heavy chain variable region gene usage in bone marrow transplant recipients: lack of somatic mutation indicates a maturational arrest [see comments]

Many recipients of bone marrow transplant (BMT) make normal amounts of serum immunoglobulin but are deficient in generating specific antibody responses to exogenous stimuli. To determine if abnormal usage of VH genes contributes to this immunodeficiency, the usage of VH genes was determined in peripheral blood B cells of four BMT recipients, two of whom had developed chronic graft versus host disease. The pattern of usage of VH3 or VH4 genes assessed at either 90 days or approximately 1 year after transplant was similar to that observed in healthy subjects and was marked by the over utilization of two elements, one VH3 and one VH4. However, the repertoires of each of the four BMT recipients appeared to be less complex than the repertoires of healthy subjects. The differences were a consequence of the accumulation of somatic mutations among rearrangements in the controls but not in the BMT recipients. The failure to accumulate somatic mutations in rearranged VH genes is consistent with a defect in antigen driven B-cell responses. These results indicate the although the VH gene content of the repertoire has normalized by 90 days posttransplant, a maturational arrest in B-cell differentiation associated with antigen activation persists for at least 1 year after BMT.     

A simple approach to prenatal diagnosis of beta-thalassemia in a geographic area where multiple mutations occur

We describe a simple approach for detecting beta-thalassemia mutations in geographic areas such as southern China where multiple mutations are known to occur. Segments of the beta-globin gene were amplified in vitro by using the polymerase chain reaction. Dot blot hybridization of the amplified DNA with oligonucleotide probes corresponding to the six mutations found in southern China could directly identify the mutations causing beta-thalassemia in the affected families. The increased number of target sequences after amplification allows the use of 35S-labeled probes, which are reusable for up to 3 months. The mutations can be determined in two days.     

Heterogeneous mechanisms of imparied lymphocyte responses in non- Hodgkin's lymphoma

Peripheral blood mononuclear cells (PBMC) from 18 untreated patients with non-Hodgkin's lymphoma (NHL) were studied to characterize the cellular mechanisms contributing to impaired in vitro lymphocyte responses after stimulation by the mitogen conconavalin A (Con-A). In vitro reactivity was quantitated by the 3H-thymidine incorporation in response to an optimal dose of Con-A. All patients demonstrated impaired in vitro reactivities compared to normal controls. These in vitro impairments were partially reversible since patient's cells precultured in media alone for 3 days demonstrated enhanced Con-A responses. In greater than half of the patients, the hyporeactive PBMC suppressed the enhanced reactivities of autologous precultured PBMC when assayed in cocultures. Suppressor activity was detected mainly in those untreated patients presenting with either constitutional symptoms or diffuse histology and in general was not marked compared to the severity of impairments. Adherent monocytes were shown to participate in the suppression of autologous lymphocyte reactivity but only appeared partially responsible for the in vitro impairments. In those patients lacking detectable suppressive activity, preculturing also enhanced Con-A reactivities and was compatible with the presence of a reversible, inhibitory mechanism differing from active suppression. Many patients' hyporeactive PBMC, however, failed to demonstrate normal responses after preculturing. This failure could not be directly attributed to aberrant regulatory populations, but rather appeared to possibly represent an additional intrinsic impairment of potentially reactive populations.     

The reliability and construct validity of the RAQoL: a rheumatoid arthritis-specific quality of life instrument

The present study was designed to test the psychometric properties of the RAQoL, a rheumatoid arthritis (RA)-specific quality of life (QoL) instrument. All stages of the development were conducted simultaneously in The Netherlands and the UK. The content of the draft measure was derived from qualitative interviews with RA patients in both countries. The final version of the RAQoL has 30 items with a 'yes'/'no' response format and takes approximately 6 min to complete. Both language versions have high internal consistency and test-retest reliability (> 0.9), and good sensitivity to discriminate between groups with various disease activity and severity. Given the excellent psychometric properties of the new instrument, it will prove to be a valuable tool for assessing quality of life in clinical trials and for monitoring patients in routine clinical practice.      

Defective interleukin-2 production and responsiveness by T cells in patients with chronic lymphocytic leukemia of B cell variety

The present studies were designed to investigate the mechanism(s) of the defective T cell proliferative response to various stimuli in patients with B cell chronic lymphocytic leukemia B-CLL. In 14 patients with advanced B-CLL (stage III or IV) we found the T cell response in the autologous (auto) and allogeneic (allo) mixed lymphocyte reaction (MLR) to be 35.7% and 30% of the controls, respectively. Proliferation in the MLR depends upon the production of and response to interleukin 2 (IL 2), a T cell growth factor. IL 2 production in eight B-CLL patients was 22% of the control. The response to IL 2 was measured by the increase in the T cell proliferation in the MLR with the addition of IL 2. T cell proliferation in both the auto and allo MLR of CLL patients was significantly lower than in the controls after the addition of IL 2. The proliferative response of normal T cells to stimulation by CLL B cells was 50% of the control. This latter response was increased to control levels when cultures were supplemented with exogenous IL 2, suggesting that CLL B cells could stimulate IL 2 receptor generation in normal T cells in an allo MLR, but not IL 2 production. The presence of IL 2 receptors on activated T cells was directly determined using anti- Tac, a monoclonal antibody with specificity for the IL 2 receptor. Of the mitogen- or MLR-activated T cells in CLL patients, 6% and 10%, respectively, expressed Tac antigen, whereas identically stimulated control T cells were 60% and 47% Tac+, respectively. Our findings suggest that T cells in B-CLL are defective in their recognition of self or foreign major histocompatibility antigens as demonstrated by their impaired responsiveness in the MLR. Thus, these cells are unable to produce IL 2 or generate IL 2 receptors.     

In vivo models of primary brain tumors: pitfalls and perspectives

Animal modeling for primary brain tumors has undergone constant development over the last 60 years, and significant improvements have been made recently with the establishment of highly invasive glioblastoma models. In this review we discuss the advantages and pitfalls of model development, focusing on chemically induced models, various xenogeneic grafts of human cell lines, including stem cell-like cell lines and biopsy spheroids. We then discuss the development of numerous genetically engineered models available to study mechanisms of tumor initiation and progression. At present it is clear that none of the current animal models fully reflects human gliomas. Yet, the various model systems have provided important insight into specific mechanisms of tumor development. In particular, it is anticipated that a combined comprehensive knowledge of the various models currently available will provide important new knowledge on target identification and the validation and development of new therapeutic strategies.     

Conservatively treated massive prolapsed discs: a 7-year follow-up

INTRODUCTION

The natural history of a lumbar hernia of the nucleus pulposus (HNP) is not fully known and clear indications for operative intervention cannot be established from the literature. Several studies have shown that the largest discs appear to have the greatest tendency to resolve. The aim of this study was to investigate whether massive prolapsed discs can be safely managed conservatively once clinical improvement has occurred.

PATIENTS AND METHODS

Thirty-seven patients were studied by clinical assessments and serial magnetic resonance imaging (MRI) over 2 years. Patients had severe sciatica at first, but began to show clinical improvement despite the large disc hernia-tions. Clinical assessment included the Lasegue test and neurological appraisal. The Oswestry Disability Index was used to measure function and changes in function. Serial MRI studies allowed measurement of volume changes of the herniated disc material over a period of time.

RESULTS

Initial follow-up at an average of 23.2 months revealed that 83% had a complete and sustained recovery at the initial follow-up. Only four patients required a discectomy. The average Oswestry disability index improved from 58% to 15%. Volumetric analysis of serial MRI scans found an average reduction of 64% in disc size. There was a poor correlation between clinical improvement and the extent of disc resolution.

CONCLUSIONS

A massive disc herniation can pursue a favourable clinical course. If early progress is shown, the long-term prognosis is very good and even massive disc herniations can be treated conservatively.