Biomedical subjects

R Carlsson

Publications and source records attributed to R Carlsson.

At least 37 records · Page 2Linked to original sources

PubMed1999

Is the esophageal squamous epithelial barrier function impaired in patients with gastroesophageal reflux disease?

BACKGROUND: A disturbed epithelial barrier function has been promoted as one factor in the pathogenesis of gastroesophageal reflux disease (GERD). We therefore studied the effect of acid perfusion on the transmural potential difference (PD) of the distal esophagus in relation to onset of reflux symptoms. METHODS: PD was assessed during perfusion with saline and with 0.1 M HCl in healthy controls (n = 17) and in GERD patients without (n = 15) or with esophagitis (n = 6) and in remission after a fundoplication (n = 10). Heartburn and other upper GI symptoms were recorded concomitantly. Endoscopy-negative patients were studied before and after omeprazole treatment. RESULTS: HCl perfusion induced more lumennegative peak PD values in patients with active GERD, regardless of the presence or absence of esophagitis, than in healthy controls. After successful therapy, the PD response to acid perfusion equalled that of healthy subjects. Acid perfusion was associated with the onset of heartburn in most patients with active GERD but in none of the healthy subjects, and less frequently after medical and surgical therapy. CONCLUSIONS: The epithelial permeability to hydrogen ions differs between healthy subjects and patients with active GERD. Effective treatment, such as omeprazole or fundoplication, might improve the barrier function.

Adolescent↗

PubMed1999

Differences in quality of life in men and women with ischemic heart disease. A prospective controlled study.

A study was conducted in Sweden in 1989-1992 to evaluate differences in quality of life (QL) in consecutive male and female patients after acute myocardial infarction (AMI), coronary artery by-pass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA). Somatic and psychological dimensions of QL were assessed by self-administered questionnaire in patients one month (n = 376) and one year (n = 349) after the cardiac event. Normal controls (n = 88) were used for comparison. Differences between gender groups, as well as between study patients and controls in somatic and psychological dimensions of QL were studied. Patients were shown to experience poorer QL when compared with demographically similar controls, especially at the one-month assessment. Female patients had poorer QL after one month (in general health, feeling of arrythmia, anxiety, depression, self-esteem, experience of sex life) and after one year (general health, anxiety, depression) compared with male patients. In all dimensions of QL a proportion of patients (19-45%) experienced a decrease in QL from the one-month to the one-year assessment occasion. Healthcare workers concerned with secondary prevention must be aware that QL differs between male and female patients in several dimensions after a cardiac event. These findings should be taken into account in the clinical management of patients, particularly for female patients who may need special attention.

Aged↗

PubMed1999

Co-ligation of CD44 on naive human tonsillar B cells induces progression towards a germinal center phenotype.

The precise signaling pathways to induce a germinal center (GC) phenotype and somatic mutations in human B cells are presently not understood. Major phenotypical hallmarks of a human GC B cell are up-regulated expression of CD10 and CD95 together with a heterogeneous expression of CD77. Activation of resting human tonsillar B cells using anti-CD40 and anti-IgM antibodies normally only induces up-regulation of CD38 and CD71 but has no effect on the typical GC markers. However, we show here that an additional co-ligation of the glycoprotein CD44 on such tonsillar B cells up-regulated the typical human GC markers CD10, CD38, CD77 and CD95, and down-regulated CD24 and CD39 as well as induced progression towards apoptosis in these cells; all characteristics of GC B cells. These data indicate a functional role of CD44 during activation of human naive B lymphocytes and in the generation of GC B cells.

Apoptosis↗

PubMed1999

Quality of life in patients with heartburn but without esophagitis: effects of treatment with omeprazole.

OBJECTIVE: Because improvement in quality of life (QoL) is an important therapeutic goal in patients with heartburn but without esophagitis, the aim of the present study was to compare the impact of omeprazole 20 mg or 10 mg daily with that of placebo on QoL in patients with heartburn as the predominant symptom. METHODS: QoL was measured at baseline and after 4 wk using two validated questionnaires, the Psychological General Well-Being (PGWB) index and the Gastrointestinal Symptom Rating Scale. RESULTS: The two questionnaires were completed by 163 patients in the omeprazole 20 mg group, 163 in the omeprazole 10 mg group, and 82 in the placebo group. The reflux dimension of the Gastrointestinal Symptom Rating Scale showed a significant improvement in terms of reflux symptoms on omeprazole 20 mg versus omeprazole 10 mg and placebo, and on omeprazole 10 mg compared with placebo. The total score of the PGWB index improved significantly more on both doses of omeprazole than on placebo. The mean scores rose from 96.8 to 103.9 on omeprazole 20 mg, from 98.4 to 106.0 on omeprazole 10 mg, and from 98.0 to 100.6 on placebo. All dimensions of the PGWB index improved on treatment with omeprazole, but the improvements were most pronounced in the dimensions depicting anxiety, depressed mood, and self-control. CONCLUSIONS: It is concluded that treatment with omeprazole 20 mg and omeprazole 10 mg restores QoL to a level comparable with that observed in a healthy population.

Adolescent↗

PubMed1998

The usefulness of a structured questionnaire in the assessment of symptomatic gastroesophageal reflux disease.

BACKGROUND: The diagnosis of gastroesophageal reflux disease (GERD) rests primarily on recognition of symptom patterns that are classical for reflux disease, but little attention has been paid to the use of a formal questionnaire for identifying such symptom patterns. METHODS: A self-administered questionnaire was developed which has seven items that focus on the nature of the symptoms and the precipitating, exacerbating, and relieving factors. The diagnostic validity of the questionnaire was tested against endoscopy and 24-h pH monitoring. A further evaluation was undertaken in patients with symptoms suggestive of GERD and in patients with non-ulcer dyspepsia, to identify factors that might predict symptom relief during treatment with omeprazole. RESULTS: When endoscopic esophageal mucosal breaks and 24-h pH data were used as criteria for the diagnosis of GERD, the questionnaire had a sensitivity of 92% but a very low specificity of 19%. Symptom relief during treatment with omeprazole was predicted by the presence of heartburn, described as 'a burning feeling rising from the stomach or lower chest up towards the neck' (P = 0.004), and 'relief from antacids' (P = 0.02). In non-ulcer dyspepsia a positive response to omeprazole was confined to the subgroup of patients who identified their main discomfort as heartburn as described above. CONCLUSION: The present questionnaire using descriptive language usefully identified heartburn in patients presenting with upper abdominal symptoms, and this symptom predicted symptom resolution during treatment with omeprazole.

Anti-Ulcer Agents↗

PubMed1998

Serum cholesterol, lifestyle, working capacity and quality of life in patients with coronary artery disease. Experiences from a hospital-based secondary prevention programme.

Coronary artery diseases (CAD) are main causes of morbidity and hospitalisation in western countries and CAD patients are at considerable risk of suffering further cardiac events. The development and evaluation of secondary prevention programmes therefore an important task. This thesis includes investigations on CAD patients admitted to a secondary prevention programme at Malmö University Hospital, Malmö, Sweden. Four weeks after discharge from the hospital, consecutive male and female patients aged 50-70 years with acute myocardial infarction (AMI) or treated with coronary artery bypass grafting (CABG) surgery were randomised to a hospital organised preventive intervention or to usual follow-up at their general practitioners. In the three studies using this randomised design, 87 (study II), 90 (study IV), and 106 (study V) intervention patients were available for evaluation. In addition, without randomisation, lipid levels at four weeks after the event was compared with levels estimated within 24 hours after onset of symptoms in 141 AMI patients (study I), and quality of life (QL) were estimated by questionnaire at one month and at one year after the event in 266 AMI, 94 CABG, and 16 percutaneous transluminal coronary angioplasty (PTCA) patients (study III). The prevention programme was effective in improving food habits but showed no impact on smoking habits or physical exercise in AMI patients (study II). The intervention also did not show any significant improvement in working capacity in AMI and CABG patients. However, working capacity improved in both intervention and reference CABG patients, most probably due to improved coronary circulation from the surgery (study IV). Cholesterol levels decreased significantly in AMI and CABG intervention patients as compared to the corresponding reference patients. This difference most likely was due to a higher frequency of lipid lowering drugs used in the intervention patients (study V). The prevention programme also decreased body mass index significantly in AMI but not in CABG patients (study V). In AMI patients receiving thrombolysis, cholesterol levels estimated within 24 hours after onset of symptoms and at four weeks after the event were virtually equal. In AMI patients not receiving thrombolysis, the lipid estimates from four weeks after the event were slightly, but significantly, above the within 24 hours from onset of symptoms estimates (study I). One month after the event, both somatic and psychological aspects of QL were negatively affected in AMI and CABG patients compared to population controls. One year after the event, patients differed from controls mainly in somatic symptoms (study III). Thus, the intervention programme was most successful in affecting lipid levels and food habits in AMI patients. QL was considerably affected in patients following an cardiac event, especially during the initial recovery phase. In addition, in patients receiving thrombolysis, cholesterol levels estimated four weeks after an AMI are reasonably valid estimates of baseline values and may be used to decide about lipid lowering interventions.

Aged↗

PubMed1998

Gastro-oesophageal reflux disease in primary care: an international study of different treatment strategies with omeprazole. International GORD Study Group.

OBJECTIVE: To assess the efficacy of omeprazole in patients presenting with troublesome reflux symptoms. DESIGN: Randomized, double-blind, parallel-group, placebo-controlled comparison. SETTING: Primary care. SUBJECTS: Patients were recruited using a symptom-based questionnaire for diagnosis of gastro-oesophageal reflux disease. INTERVENTIONS: After endoscopy, patients without endoscopic oesophagitis were randomized to omeprazole 20 mg (Ome20), omeprazole 10 mg (Ome10) or placebo once daily for 4 weeks (n = 261) and those with oesophagitis (except circumferential/ulcerative) were randomized to receive either Ome20 or Ome10 once daily for 4 weeks (n = 277). Patients not symptom-free at 4 weeks received open treatment with Ome20 once daily for a further 4 weeks. Those symptom-free at 4-8 weeks were followed up for 6 months off treatment, to see whether their symptoms recurred. MAIN OUTCOME MEASURE: Complete upper GI symptom relief during week 4 on Ome20 or Ome10 in patients with or without endoscopic oesophagitis. RESULTS: Forty one percent of all patients on Ome20 and 35% on Ome10 reported complete relief from upper GI symptoms during week 4, whilst 73% of the patients on Ome20 and 62% on Ome10 obtained sufficient control. Complete relief during week 4 was reported by 19% of endoscopy-negative patients on placebo, and sufficient control by 35%. Endoscopic healing at 4 weeks occurred in 76% of oesophagitis patients on Ome20 and in 56% on Ome10. After 6 months off treatment, 90% of patients with oesophagitis and 75% of endoscopy-negative patients reported symptomatic relapse. CONCLUSION: Both 10 mg and 20 mg of omeprazole gave effective relief of symptoms, although 20 mg gave superior healing in patients with oesophagitis. After cessation of treatment, symptomatic relapse was rapid and frequent in both endoscopy-positive and endoscopy-negative patients.

Adolescent↗

PubMed1997

Terminal differentiation of human germinal center B cells in vitro.

In order to define an in vitro culture system allowing growth of single human germinal center B cells (GC-B), we have studied the proliferation and differentiation of human tonsillar GC-B, and subsets thereof, when cultured together with murine EL-4 thymoma cells in the "EL-4 system." The cells were analyzed and compared to resting tonsillar B cells with respect to phenotypic changes, proliferation, Ig secretion, intracellular Ig levels, and growth abilities under limiting dilution conditions. It was found that GC-B differentiated terminally to Ig-secreting cells with the phenotypic features of plasma cells in a similar manner to tonsillar resting B cells. The GC-B proliferated for 4-5 days, followed by a loss of GC-B phenotype and an increase in intracellular immunoglobulin levels. Over a 10-day culture period a larger proportion of the Ig produced by GC-B was IgG and IgA, as compared to resting B cells, indicating that these cells switched isotype more easily or had already switched in the germinal center prior to the culture period. Analysis of frequencies of Ig-producing cells revealed that 1/3.8 of GC-B and less than 1/10 of the centroblast B cell subpopulation (CB-B) differentiated toward Ig-producing cells when cultured in the EL-4 system whereas 1/1.25 and 1/1.5 of peripheral blood B cells (PBL-B) and resting tonsillar B cells did so, respectively. Taken together, these findings show that tonsillar GC-B differentiate in a similar manner to resting B cells when cultured in the EL-4 system, and we conclude that these conditions allow manipulation of GC-B in single cell cultures in vitro.

Animals↗

PubMed1997

Human monoclonal antibodies specific for the tumour associated Thomsen-Friedenreich antigen.

Five hybridomas producing human monoclonal antibodies (MAbs) of IgA and IgM isotypes reacting with the tumour associated TF antigen were generated after in vitro immunisation or antigen specific isolation of normal peripheral blood B cells using asialoglycophorin, a TF containing antigen. All 5 antibodies produced by the hybridomas bound strongly to asialoglycophorin and to synthetic glycoprotein containing the TF-epitope, with preference to the beta form (Galb1-3GalNAc-beta-O-CETE-BSA) as compared to the alpha form (Galbl-3GalNAc-alpha-O-APE-HSA) in ELISA. Flow cytometry analysis revealed binding to carcinoma cell lines of different origin such as breast, colon, pancreas, ovary, bladder, lung and, in addition, to some tumour cell lines of haematopoietic origin. Immunohistochemical analysis of tumour tissues revealed staining patterns typical for mucins, and the antibodies were found to bind to glycoproteins among the MUC-1 positive high m.w. fraction shed from a TF antigen positive ovarian carcinoma cell line.

Animals↗

PubMed1997

Prognostic factors influencing relapse of oesophagitis during maintenance therapy with antisecretory drugs: a meta-analysis of long-term omeprazole trials.

BACKGROUND: This meta-analysis investigated factors that may affect the risk of relapse of oesophagitis, and evaluated the predictive value of symptoms for the presence of relapse during long-term treatment. METHODS: Individual data from 1154 patients included in five independently conducted, randomized, long-term clinical trials of the efficacy of different dosage regimens of omeprazole, standard ranitidine treatment and placebo for the prevention of relapse of oesophagitis were pooled for this meta-analysis. The therapeutic regimens studied were omeprazole 20 mg o.m. (OME20) in 366 patients, omeprazole 10 mg o.m. (OME10) in 225 patients, omeprazole 20 mg weekends (OMEW) in 235 patients, ranitidine 150 mg b.d. (RAN) in 179 patients, or placebo (PLA) in 149 patients. RESULTS: OME20 maintained 82.4% (95% CI: 78.2-86.6%) of patients in endoscopic remission over the 6-month period compared to 71.9% (95% CI: 65.5-78.3%) for OME10, 52.3% (95% CI: 44.4-60.1%) for RAN, 42.7% (95% CI: 35.8-49.5%) for OMEW, and 10.6% (95% CI: 5.0-16.3%) for PLA. A Cox's regression analysis of time to recurrence of oesophagitis showed that four factors were associated with a higher relapse rate during placebo and active maintenance therapy: (a) pre-treatment severity of oesophagitis (P < 0.0001), (b) young age (P = 0.01), (c) non-smoking (P = 0.02) and (d) moderate/severe regurgitation before entry into the trials (P = 0.03). Asymptomatic relapse of oesophagitis was uncommon, being found in only 8.6% of the patients. CONCLUSIONS: Maintenance treatment with omeprazole 10 and 20 mg daily is superior to all other regimens tested, and is only marginally influenced by the pretreatment severity of oesophagitis. Age contributes to the factors that influence the outcome during long-term treatment with omeprazole. Symptom relief is highly predictive for the maintenance of healing.

Adolescent↗

PubMed1997

Quality of life in patients with ischaemic heart disease: a prospective controlled study.

OBJECTIVES: To assess quality of life in patients after acute myocardial infarction (AMI), coronary artery by-pass grafting surgery (CABG) and percutaneous transluminal coronary angioplasty (PTCA) as compared with healthy controls. DESIGN: Self-administered questionnaires were completed 1 month and 1 year after the event. SETTING: Department of Cardiology, University Hospital, Malmö, Sweden; 1989-1992. SUBJECTS: 296 AMI, 99 CABG, 18 PTCA patients and 88 randomly selected healthy controls were included; 349 patients completed the entire programme. MAIN OUTCOME MEASURES: Quality of life in the dimensions of perceived general health, thoracic pain, breathlessness, feeling of arrhythmia, anxiety, depression, self-esteem, experience of social life and sex life. RESULTS: Patients differed from controls in both psychological and somatic aspects of QL after 1 month. Furthermore, 1 month after the event AMI patients experienced more anxiety (P = 0.001) than CABG patients, whilst CABG patients experienced a poorer sex life (P < 0.001) than AMI patients. One year after the event patients differed from controls primarily in somatic symptoms: no significant differences were found across patient groups. Patients who sought emergency out-patient care during the follow-up year for clinically diagnosed angina pectoris or cardiac incompensation had reported higher levels of thoracic pain (P < 0.001) and breathlessness (P < 0.001) at 1 month follow-up than patients who did not seek such care. CONCLUSIONS: Quality of life is considerably affected in patients following a cardiac event, especially during the initial recovery phase. Although substantial improvement in quality of life occurs over time, the persistence of residual distress at 1-year follow-up is a challenge for clinicians concerned with the full rehabilitation of the cardiac patient.

Angina Pectoris↗

PubMed1997

Ligation of MHC class I induces apoptosis in human pre-B cell lines, in promyelocytic cell lines and in CD40-stimulated mature B cells.

A murine mAb (BAL-1) was previously shown to induce apoptosis when cross-linked on the cell surface of different B acute lymphocytic leukemia (ALL) and pro-myelocytic cell lines. The present study shows that BAL-1 specifically recognizes the MHC class I (MHC-I). The apoptotic response was not dependent on the epitope specificity, since other anti-MHC-I antibodies, reacting with different monomorphic determinants of the alpha chain or beta 2-microglobulin, also induced apoptosis in these cells. However, external cross-linking of antibodies was strictly required for the apoptotic effect. Among cells originating from mature peripheral blood B cells, anti-CD40-stimulated cells were susceptible to anti-MHC-I-induced apoptosis, whereas B cells activated with Staphylococcus aureus Cowan I (SAC) or with the superantigen staphylococcal enterotoxin A (SEA) were non-responsive. Mature SEA-activated T cells were also resistant to MHC-I-induced apoptosis. In situ terminal deoxynucleotidyl transferase staining of apoptotic cells at various stages during MHC-I-induced cell death revealed that apoptosis occurred predominantly in the G2/M phase of the cell cycle, with the first apoptotic cells appearing after approximately 12 h of incubation. These results suggest a role for MHC-I-mediated apoptosis during differentiation and activation of certain hematopoietic cells.

Animals↗

PubMed1997

Influence of coronary nursing management follow up on lifestyle after acute myocardial infarction.

OBJECTIVE: To examine the ability of a secondary prevention programme to improve the lifestyle in myocardial infarction patients aged 50-70 years. DESIGN: Habitual physical activity, food habits, and smoking habits were assessed from questionnaires at admission to hospital and at the one year follow up. Initially, all patients were invited to join an exercise programme and were informed about cardiovascular risk factors. Four weeks after discharge from the hospital, 87 patients were randomised to follow up at the coronary prevention unit by a special trained nurse (the intervention group), and 81 to follow up by their general practitioners (the usual care group). After randomisation, the intervention group was educated about the effects of smoking cessation, dietary management, and regular physical activity. The intervention group also participated in a physical training programme two to three times weekly for 10-12 weeks. MAIN RESULTS: 89% of the patients referred to the intervention group improved their food habits compared with 62% of the patients referred to the usual care group (P = 0.008). Furthermore, 50% of the smokers referred to the intervention group stopped smoking compared to 29% in the usual care group (P = 0.09). Changes in physical activity did not differ between the groups. CONCLUSIONS: This secondary prevention programme based on a nurse rehabilitator was successful in improving food habits in patients with acute myocardial infarction. Initiating the smoking cessation programme during the hospital stay followed by repeated counselling during follow up might have improved the results. The exercise programme had no advantage in supporting physical activity compared to usual care.

Exercise↗

PubMed1997

Heartburn without oesophagitis: efficacy of omeprazole therapy and features determining therapeutic response.

BACKGROUND: Data are limited on the value of effective antisecretory therapy in the relief of heartburn in patients without oesophagitis. METHODS: Patients with heartburn, without endoscopic signs of oesophagitis, were randomized to double-blind treatment with omeprazole, 20 or 10 mg once daily, or placebo, for 4 weeks (n = 509). Pre-treatment oesophageal acid exposure was assessed using 24-h intra-oesophageal pH monitoring. Heartburn was assessed at 2 and 4 weeks. RESULTS: At 4 weeks the proportion of patients with complete absence of heartburn was 46% (95% confidence interval, 39-53%) with 20 mg omeprazole, 31% (25-38%) with 10 mg omeprazole, and 13% (7-20%) with placebo. Satisfaction with therapy was reported by 66%, 57%, and 31% of the patients, respectively. CONCLUSION: Omeprazole, 20 and 10 mg once daily, provides rapid relief of heartburn in patients without endoscopic oesophagitis.

Anti-Ulcer Agents↗

PubMed1997

Haemostatic variables in Pacific Islanders apparently free from stroke and ischaemic heart disease--the Kitava Study.

We cross-sectionally measured plasminogen activator inhibitor-1 (PAI-1) activity, fibrinogen, factor VII (FVII:C) and VIII (FVIII:C) coagulant activity, and von Willebrand factor antigen (VWF:Ag) in 162 traditional horticulturalists older than 40 years from the tropical island of Kitava, Papua New Guinea, where the intake of western food is negligible and where stroke and ischaemic heart disease appear to be absent. Identical analyses were made in Swedish subjects of comparable ages. Kitavams had markedly lower PAI-1 activity, with 85% of males and 100% of females having PAI-1 activity < or = 5 U/ml, as compared with 22 and 14% in Swedish males and females (p < 0.0001). Surprisingly, Kitavans also had higher FVII:C. FVIII:C and VWF:Ag. Fibrinogen was 10% lower in Kitavan males while 25% higher in Kitavan females. The very low PAI-1 activity in Kitavans may explain some of their apparent freedom from cardiovascular disease and probably relates to their extreme leanness.

Adult↗

PubMed1996

Telomerase activation in normal B lymphocytes and non-Hodgkin's lymphomas.

Activation of telomerase seems to be a prerequisite for immortalization and is found in permanent cell lines and most malignant tumors. Normal somatic cells are generally telomerase negative, except for bone marrow stem cells. Weak activity is also present in peripheral blood cells. In the present study strong telomerase activity was demonstrated in vivo in normal mature cells of the immune system, as well as in malignant lymphomas. Benign lymph nodes had lower telomerase activity than benign tonsils, which exhibited intermediate to high activity comparable with findings in malignant lymphomas. In benign tonsils the activity seemed to be restricted to germinal center B cells. In benign lymphoid tissues telomerase activity correlated with B-cell numbers and cell proliferation, but this was not observed in the lymphoma group. High-grade lymphomas exhibited higher levels of telomerase compared with low-grade cases. The data showed that in vivo activation of telomerase is a characteristic feature of germinal center B cells. Different signals for activation of telomerase are likely to exist, one of them being immune stimulation. The data suggest that telomerase activity in malignant lymphomas can be explained by an "induction and retention" model, ie, transformation occurs in a normal, mature B cell with reactivated telomerase, which is retained in the neoplastic clone.

B-Lymphocytes↗

PubMed1996

Immunoglobulin production induced by CD57+ GC-derived helper T cells in vitro requires addition of exogenous IL-2.

Germinal centers (GC) are well-defined areas in lymphoid organs were B cells proliferate and differentiate in response to T-cell-dependent antigens. The GC comprises B cells, follicular dendritic cells, tangible body macrophages, and a low number of CD4+ T cells. A large portion of these T cells expresses CD57. We have examined the ability of the CD4+ CD57+ GC T cells to become activated and to take part in B cell activation processes. These T cells coexpress CD45RO, CD69, CD28, and upon mitogenic stimulation CD25. The cell population was found neither to contain nor to be able to produce any specific mRNA for IL-2, IL-4, and IFN-gamma upon activation. Levels of mRNA encoding CD40 ligand was also undetectable under similar conditions. Furthermore, in contrast to ordinary CD4+ T cells, this population expressing CD57 was unable to induce B cells to Ig production in the presence of pokeweed mitogen or SEA unless IL-2 was added to the cultures. However, despite their apparent lack of function CD4+ CD57+ GC T cells were found to rescue GC B cells from cell death in vitro to the same extent as CD4+ CD57+ Th cells. The phenotypical and functional differences found between these Th cells and regular Th-cells suggest that they either represent a T cell subset with distinct properties within the GC yet to be determined or that they represent T cells, late in the immune response, having lost most of their original functions and capabilities.

B-Lymphocytes↗

PubMed1995

CD4+CD57+ T cells derived from peripheral blood do not support immunoglobulin production by B cells.

A small subpopulation of CD4+ T cells found in peripheral blood coexpresses the CD57+ marker normally found on, e.g., NK cells. It is known that this population occurs in a higher frequency in certain diseases. The same antigen has also been shown to be expressed on CD4+ T cells derived from germinal centers. The localization of this cell population to specialized lymphoid structures suggests that it may play a role in the evolution of the antibody response following antigenic stimulation in vivo. We have examined the ability of peripheral blood helper T cells coexpressing CD57 to participate in B cell activation/differentiation and evaluated their responses to polyclonal stimulation. The CD4+CD57+ T cells do not express mRNA for a number of different cytokines or for the CD40 ligand after activation in vitro. Furthermore these cells do not induce differentiation of B cells into immunoglobulin-producing cells. Consequently, despite their CD4 phenotype and their ability to be activated, to express the IL-2 receptor, and to enter into the cell cycle, they do not act as T helper cells under conditions where CD4+/CD57- cells normally do so. The findings suggest that this peripheral blood helper T cell population is functionally different from regular CD4+ T cells. The basis for the lack of proper costimulatory signals for immunoglobulin production might be related to the low expression of CD28.

Antigens, CD↗