Biomedical subjects

W M Howell

Publications and source records attributed to W M Howell.

At least 19 recordsLinked to original sources

PubMed2006

Genotype of galectin 2 (LGALS2) is associated with insulin-glucose profile in the British Women's Heart and Health Study.

AIMS/HYPOTHESIS: It has been suggested that the gene encoding lymphotoxin-alpha (LTA) is associated with insulin resistance, and genetic association studies in the LTA region offer some support for this. However, LTA is in linkage disequilibrium with both the HLA gene cluster and the gene encoding TNF-alpha, making inferences about causality difficult. In this study, we used the galectin 2 (LGALS2) genotype, which affects LTA secretion but is located on another chromosome than the HLA gene cluster or TNF, to examine the relationship between the LTA pathway and traits of the metabolic syndrome. SUBJECTS: A cross-sectional genetic association study was carried out in 3,272 British women of European origin who were aged 60 to 79 years and were randomly selected from the community. RESULTS: Fasting plasma glucose and serum insulin were statistically significantly associated with LGALS2 rs7291467, with this association being independent of BMI and WHR. The mean difference in fasting insulin per minor allele was -4% (p=0.01 for trend by allele) and the mean per minor allele difference in fasting glucose was -2% (p=0.02 for trend by allele). When women with known diabetes were excluded from the analyses the findings did not differ from those for the whole cohort. CONCLUSIONS/INTERPRETATION: Our findings for the physically unlinked LGALS2, invite further study of LGALS2 specifically and the LTA pathway generally for their influence on glucose-insulin regulation.

Aged↗

PubMed2005

Immunomonitoring of renal transplant recipients in the early posttransplant period by sequential analysis of chemokine and chemokine receptor gene expression in peripheral blood mononuclear cells.

INTRODUCTION: We sought to determine whether sequential changes in chemokine ligand/receptor gene expression in the early posttransplant period of human renal allografts can be detected in peripheral blood mononuclear cells (PBMCs) and whether any such changes are predictive of clinical events. METHODS: Blood samples from 106 renal transplant recipients and 29 donor nephrectomy patients were taken preoperatively and daily for 14 days. Within the study period 22 patients had biopsy-proven acute rejection. From each blood sample PBMCs were separated and gene expression levels for chemokines CCL3, CCL4, CCL5, CXCL10, and their receptors CCR1, CCR5, and CXCR3, were determined using real-time quantitative PCR. RESULTS: Different gene expression patterns were seen between the rejector and nonrejector groups with decreases in CCL4 and CCR5 expression on days 6 to 8 and increases in CCR1 expression on days 9 and 10 posttransplant. With CXCL10, decreases in expression were seen in the nonrejector group but increases were seen in the rejector group posttransplant. With data aligned to time of rejection diagnosis, statistically significant increases, that preceded the clinical detection of acute rejection were seen in CCR1 and CXCL10 expression. Both their expression levels returned to pretransplant baseline values after successful antirejection therapy. CONCLUSION: We have demonstrated that changes in chemokine receptor/ligand gene expression by sequential monitoring in PBMCs can be detected in the early posttransplant period. In particular, CCR1 and CXCL10, which showed increased expression prior to rejection and returned to baseline levels with antirejection therapy, may have potential use in immunomonitoring and as predictive factors of rejection prior to its clinical manifestation.

Chemokines↗

PubMed2005

An interleukin-10 promoter polymorphism may influence tumor development in renal cell carcinoma.

PURPOSE: Polymorphisms in the promoter of the interleukin-10 (IL-10) gene may influence tumor development by altering the levels of IL-10 present in the serum or tumor microenvironment. In this study we looked for evidence of specific polymorphisms of the IL-10 promoter and whether lymphocyte expression of IL-10 correlates with specific genotypes. MATERIALS AND METHODS: Archival, paraffin embedded renal cell carcinoma tissue from 166 patients and 161 controls were genotyped for the IL-10-1082 single nucleotide polymorphism using real-time polymerase chain reaction. IL-10 protein expression in peripheral blood lymphocytes was assessed by standard enzyme-linked immunoassay in 32 patients with renal cancer. RESULTS: Patient-to-control comparisons identified the AA genotype to be significantly greater in patients with renal cell carcinoma (44% vs 30%, p <0.05). However, study of IL-10 protein expression in peripheral blood lymphocytes from patients with renal cancer showed no statistical difference in IL-10 expression among the GG, AA or AG genotypes. CONCLUSIONS: We found that there was a significantly larger proportion of patients with renal cell carcinoma with the AA homozygous genotype than in a normal population cohort. This result is in accordance with those in previous studies of prostate cancer and cutaneous malignant melanoma. In contrast to previous studies of other tumor types, no correlation could be established between IL-10-1082 polymorphism and serum IL-10.

Adult↗

PubMed2005

ICAM-1 polymorphisms and development of cutaneous malignant melanoma.

Tumour growth in cutaneous malignant melanoma (CMM) is mediated by cell adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1). ICAM-1 expression is associated with increasing Breslow thickness of vertical growth-phase tumours and, in patients with stage 1 disease, may be associated with disease free and patient survival. In this study we have investigated whether two single nucleotide polymorphisms (SNPs) in the ICAM-1 gene encoding amino acid substitutions in codons 241 and 469 of the expressed ICAM-1 molecule are associated with susceptibility to and markers of prognosis (including tumour Breslow thickness) in CMM. A total of 164 CMM patients and 264 cancer-free controls were genotyped for these SNPs by the 5' nuclease assay for allelic discrimination (TaqMan). No genotypes showed any significant associations with CMM susceptibility, although there was a non-significant increase in frequency of the ICAM-1 469 AA genotype among CMM patients vs. controls (38.4% vs. 29.9%; P = 0.11). However, the ICAM-1 241 GG genotype was significantly decreased in frequency among patients with primary invasive tumours of greater Breslow thickness (72.5% vs. 91.2%; P = 0.013; OR = 0.25 (0.072-0.85)). These results provide no evidence for a role for the ICAM-1 codon 241 and 469 SNPs in determining susceptibility to CMM, but provide preliminary evidence that the role of ICAM-1 polymorphism in modulating tumour growth in CMM requires further investigation in a larger study group.

Adult↗

PubMed2005

HLA and eye disease: a synopsis.

Human leukocyte antigen (HLA) gene products have been implicated in the pathogenesis of an increasing number of eye diseases, mainly inflammatory in nature. This perspective reviews the current hypotheses for why HLA polymorphisms are associated with specific eye diseases. Statistical problems in studies involving HLA associations are discussed, and possible solutions outlined. The relevance of HLA testing in routine ophthalmic practice, its practical and cost implications is also assessed.

Costs and Cost Analysis↗

PubMed2005

Influence of cytokine and ICAM-1 gene polymorphisms on susceptibility to chronic pancreatitis.

AIMS: To test the hypothesis that single nucleotide polymorphisms (SNPs) within genes (or their promoter regions) encoding cytokines, growth factors, and intercellular adhesion molecules modulate the risk of development of chronic pancreatitis (CP). METHODS: DNA was extracted from peripheral blood leucocytes or formalin fixed, paraffin wax embedded tissue from 53 patients with CP and 266 healthy controls. SNPs within the interleukin 1beta (IL-1beta), IL-6, IL-8, tumour necrosis factor alpha (TNFalpha) and vascular endothelial growth factor (VEGF) gene promoter regions and the transforming growth factor beta1 (TGFbeta1) and intercellular cell adhesion molecule 1 (ICAM-1) genes were genotyped by the amplification refractory mutation system polymerase chain reaction or 5' nuclease (Taqman) techniques. Patient-control comparisons were made using 2 x 2 contingency tables and chi2 analyses. RESULTS: A non-significant decrease in the frequency of the IL-8 -251 AA genotype and a non-significant increase in the frequency of the ICAM-1 +469 GA genotype was seen in patients compared with controls. No associations were identified between SNPs in the promoter regions of the IL-1beta, IL-6, or TNFalpha proinflammatory cytokines genes or the TGFbeta1 and VEGF genes and susceptibility to CP. CONCLUSIONS: This preliminary study suggests that genetic polymorphism within several cytokine genes is unlikely to influence susceptibility to CP, but the possible role of IL-8 and ICAM-1 polymorphisms in the development of this disease requires further investigation.

Adolescent↗

PubMed2005

VEGF polymorphisms and severity of atherosclerosis.

INTRODUCTION: Vascular endothelial growth factor (VEGF) is a potent angiogenic factor, and neovascularisation has been shown to be important in atherosclerotic plaque development. There is some disagreement as to whether VEGF acts as a pro-atherosclerotic or anti-atherosclerotic factor. In the present study we have sought to clarify this by determining genotypes and haplotypes for three reportedly functional VEGF SNPs in a large series of well documented coronary atherosclerosis patients. METHODS: VEGF -2578, -1154, and -634 single nucleotide polymorphisms were genotyped in 984 subjects from the Southampton Atherosclerosis Study, using the 5' nuclease assay for allelic discrimination (TaqMan). RESULTS: VEGF -2578 genotypes showed a significantly different distribution in patients without myocardial infarction when stratified according to number of diseased arteries. VEGF -2578 was also associated with mean number of stenotic segments in the same patient group. The AA genotype was a risk factor and CC was protective. These associations were significant before and after adjustment for classic risk factors, and were reflected in associations between VEGF haplotypes and the number of diseased arteries and stenotic segments. As VEGF -2578 CC has been provisionally shown to be associated with higher VEGF expression than the AA genotype, these results are consistent with a protective effect for VEGF in atherosclerosis development. Some changes in VEGF -1154 genotype frequencies were also detected, but no significant associations were detected for any one particular genotype. CONCLUSIONS: This study provides preliminary evidence that VEGF polymorphism is associated with development of atherosclerosis, possibly via regulation of VEGF expression, supporting a protective effect for VEGF in atherosclerosis. These results require replication in an independent study group, combined with study of additional candidate polymorphisms in the VEGF gene.

Coronary Artery Disease↗

PubMed2004

Lack of association of HLA class I genes and TNF alpha-308 polymorphism in toluene diisocyanate-induced asthma.

BACKGROUND: Toluene diisocyanate (TDI)-induced asthma is a common cause of occupational asthma and it affects 5-15% of the exposed population suggesting an underlying genetic susceptibility. METHODS: To investigate the role of genetic factors in the development of TDI-induced asthma, we analyzed the distribution of human leukocyte antigen (HLA) class I genes and of tumor necrosis factor (TNF)-alpha A-308G polymorphism in 142 patients with TDI-induced asthma and in 50 asymptomatic exposed subjects. RESULTS: Neither the distribution of HLA class I antigens nor the distribution of TNF-alpha A-308G polymorphism was different between patients with TDI-induced asthma and asymptomatic exposed subjects. CONCLUSIONS: These results suggest that HLA class I antigens and TNF-alpha A-308G are not associated with susceptibility or resistance to the development of TDI-induced asthma.

Adult↗

PubMed2004

Cytokine gene polymorphisms and breast cancer susceptibility and prognosis.

Single nucleotide polymorphisms (SNPs) in the promoter regions of cytokine genes are associated with differential levels of cytokine expression. We hypothesized that these SNPs might influence breast tumour development and progression by affecting the efficiency of the antitumour immune response and/or pathways of angiogenesis. A total of 144 female breast cancer patients and 263 cancer-free population controls were genotyped for the interleukin (IL)-1beta-511 (T/C), IL-6 -174 (G/C), tumour necrosis factor (TNF)-alpha-308 (A/G), IL-10 -1082 (A/G), IL-8 -251 (A/T) and vascular endothelial growth factor (VEGF) -1154 (A/G) SNPs, using amplification refractory mutation system polymerase chain reaction (ARMS-PCR) and TaqMan (Applied Biosystems, Foster City, CA, USA) 5' nuclease assays for allelic discrimination. No significant associations were seen. Patient-control comparisons revealed a non-significant trend for association between the TNF-alpha-308 GG genotype and breast cancer compared to controls (79.7 vs. 68.2%, P = 0.03, Pc = 0.54). Stratification of the patient group according to the Nottingham Prognostic Index and individual prognostic factors revealed trends for association between IL-6 -174 GC and IL-8 -251 AA genotypes and markers of poor prognosis (P = 0.04, Pc = 0.72 and P = 0.02, Pc = 0.36, respectively). There were also trends for associations between VEGF -1154 AG and IL-1beta-511 TC genotypes and markers of good prognosis (P = 0.02, Pc = 0.36 and P = 0.05, Pc = 0.90, respectively). These results suggest that the role of cytokine promoter SNPs in both susceptibility to and prognosis in breast cancer requires further investigation in a larger study.

Adult↗

PubMed2003

Cytokine gene single nucleotide polymorphisms and susceptibility to and prognosis in cutaneous malignant melanoma.

Cutaneous malignant melanoma (CMM) is a potentially fatal malignancy in which exposure to UV light is the most important risk factor. Several lines of evidence suggest that CMM patients develop an immune response to their tumours, although, in most cases, anti-tumour immune responses are insufficient to abrogate tumour development. Polymorphism in genes regulating the immune response and cell growth may result in increased susceptibility to and/or poorer prognosis in certain individuals. In this study, we addressed whether single nucleotide polymorphisms (SNPs) associated with differential expression of selected pro- and anti-inflammatory cytokines and growth factors [interleukin (IL)-1beta-35 and -511, IL-2 -330, IL-4 -590, IL-6 -174, IL-8 -251, interferon (IFN)-gamma+874 and transforming growth factor (TGF)beta1 +915] or as markers of candidate cytokine genes (IL-12 +1188) are associated with susceptibility to or known prognostic indicators (e.g. initial tumour growth phase, Breslow thickness, mitotic count in vertical growth phase tumours, tumour regression) in CMM. One hundred and sixty-nine British caucasian CMM patients and 261 controls were included in the study and all SNPs were genotyped by ARMS-PCR. No SNP genotypes or alleles showed significant associations with CMM susceptibility and only the IL-1beta-511 TT genotype was associated with thinner invasive tumours at presentation, as assessed by Breslow thickness at the clinically significant cut-off point of 1.5 mm [occurring in 2/51 (3.9%) thicker vs. 14/78 (17.9%) thinner tumours (P = 0.03; relative risk = 0.29 (95% confidence interval 0.05-0.95)]. These findings suggest that - with the possible exception of IL-1beta- genetic variation associated with differential expression of the selected pro- and anti-inflammatory cytokines is unlikely to play a major role in susceptibility to and prognosis in CMM.

Case-Control Studies↗

PubMed2002

Influence of vascular endothelial growth factor single nucleotide polymorphisms on tumour development in cutaneous malignant melanoma.

Vascular endothelial growth factor (VEGF) is a potent regulator of vasculogenesis and tumour angiogenesis. We have investigated whether the VEGF -2578, -1154, +405 and +936 SNPs and associated haplotypes confer susceptibility to and/or influence prognosis in cutaneous malignant melanoma (CMM) skin cancer. A total of 152 CMM patients and 266 controls were genotyped for VEGF promoter SNPs by ARMS-PCR. Strong linkage disequilibrium between the -2578, -1154 and +405 SNPs was detected (association, rho = 0.488-0.965), but not between these SNPs and SNP +936 (association, rho = 0.004-0.130). No SNPs or three SNP haplotypes (-2578, -1154, +405) were significantly associated with CMM, although a number of non-significant trends were observed. However, the VEGF -1154 AA genotype and -2578, -1154, +405 CAC haplotype were both significantly associated with less advanced (Stage 1) disease (P = 0.03). In addition, the VEGF -1154 AA genotype was associated with thinner primary vertical growth phase tumours (P = 0.002), while VEGF -1154 GG was associated with thicker primary tumours (P = 0.02). These preliminary results indicate that VEGF genotype may influence tumour growth in CMM, possibly via the effects of differential VEGF expression on tumour angiogenesis.

Endothelial Growth Factors↗

PubMed2002

Influence of TNFalpha and LTalpha single nucleotide polymorphisms on susceptibility to and prognosis in cutaneous malignant melanoma in the British population.

Cutaneous malignant melanoma (CMM) is a potentially fatal malignancy in which exposure to UV light is the most important risk factor. Several lines of evidence suggest that increased expression of tumour necrosis factor (TNF) alpha, upregulated by UV exposure, may contribute to tumour escape from the immune response. In this study, we addressed whether single nucleotide polymorphisms (SNPs) in the TNFalpha promoter and lymphotoxin (LT) alpha gene are associated with susceptibility to or known prognostic indicators (e.g. initial tumour growth phase, Breslow thickness, mitotic count in vertical growth phase tumours, and tumour regression) in CMM. One hundred and forty-six British Caucasian CMM patients and 220 controls were typed for TNFalpha-376, -308 and -238 and LTalpha+252 SNPs by ARMS-PCR. Only the TNFalpha -238 GG (P = 0.05) and GA (P = 0.03) genotypes showed slight, but significant, associations with CMM, while LTalpha+252 AA was associated with a higher mitotic count in vertical growth phase tumours (P = 0.02). Both TNFalpha-238 and LTalpha+252 SNPs showed linkage disequilibrium with HLA-DQB1*0303 and *0301 alleles, variably implicated in CMM susceptibility/prognosis. In addition, TNFalpha-238, -308, LTalpha+252 haplotypes were assigned and compared. The GGA haplotype showed a modest association with CMM (P = 0.04) and with stage of disease (P = 0.03) and initial growth phase in CMM (P = 0.02), but these associations were only significant when P-values were uncorrected. Unlike basal cell carcinoma, these preliminary findings suggest that genetic variation associated with differential TNFalpha and LTalpha production is unlikely to play a major, independent role in susceptibility to, and perhaps prognosis in, CMM.

Case-Control Studies↗

PubMed2001

Sequential monitoring of peripheral T-lymphocyte cytokine gene expression in the early post renal allograft period.

BACKGROUND: Despite numerous studies, the precise role of cytokines in acute renal allograft rejection remains unclear. In this study we have monitored sequential changes in peripheral T cell cytokine gene expression, correlating the changes with clinical events after adult renal transplantation, to provide a deeper insight of the role of cytokines in allograft rejection. METHODS: Sequential changes in peripheral Th-1 [interleukin- (IL) 2 and interferon-gamma] and Th-2 (IL-4, IL-5, IL-10, and IL-13) cytokine gene expression in 43 patients with (n=15) and without (n=28) episodes of biopsy-proven rejection was monitored in the first 6 weeks after renal transplantation using a sensitive, semi-quantitative reverse-transcriptase polymerase chain reaction ELISA approach. RESULTS: Th-2 cytokines: IL-5 and IL13 expression increased before and during acute rejection, and decreased after successful antirejection therapy. A significant fall in IL-4 expression after transplantation and subsequent return to its baseline level of expression was observed in both nonrejectors and rejectors. IL-10 showed persistently high expression in nonrejectors, but in rejectors the expression fell during acute rejection, with a subsequent rise after antirejection therapy. Th-1 cytokines: IL-2 and IFN-gamma decreased in expression in the first week posttransplant in the rejectors, at the time of acute rejection (IL-2 only) and immediately after completion of antirejection therapy. CONCLUSIONS: Sequential monitoring of peripheral T cell cytokine gene expression after renal transplantation detected changes in expression that correlated with episodes of acute rejection and response to antirejection therapy. This approach may be applicable in the clinical laboratory for monitoring posttransplant changes in T cell alloreactivity and immunosuppression.

Adult↗

PubMed2001

Invasiveness of cutaneous malignant melanoma is influenced by matrix metalloproteinase 1 gene polymorphism.

The matrix metalloproteinases (MMPs) are implicated in connective tissue destruction during cancer invasion and metastasis. A naturally occurring variant arising from the insertion or deletion of a guanine in the promoter of the MMP-1 gene has recently been reported and shown to influence its transcriptional activity in melanoma cells. In this study, MMP-1 genotype was determined in 139 Caucasian patients with cutaneous malignant melanoma. The insertion allele was associated with deep invasive, and therefore poorer-prognosis, primary tumors [(34% of patients with vertical growth phase tumor were homozygous for the insertion allele compared with 17% of patients with horizontal growth phase tumor (P = 0.0333; odds ratio = 2.51)]. These data suggest that the invasiveness of cutaneous malignant melanoma is influenced by variation in the MMP-1 gene promoter that affects MMP-1 expression.

Cell Division↗

PubMed2001

Gonopodium development in normal male and 11-ketotestosterone-treated female mosquitofish (Gambusia affinis): a quantitative study using computer image analysis.

Mature male mosquitofish possess a highly modified anal fin called a gonopodium that develops from an unmodified female-like anal fin under the influence of endogenous androgens at sexual maturity. Although females do not normally develop gonopodia, their anal fins can be induced to develop into gonopodium-like structures by the administration of androgens. We used computer image analysis techniques to quantify the morphological changes in the anal fins of normal male and female mosquitofish during growth and development and the changes that occur in females exposed to an androgen, 11-ketotestosterone. The mosquitofish anal fin is a useful bioassay system for quantifying the effects of known or suspected environmental androgens.

Aging↗

PubMed2001

Influence of patient and donor cytokine genotypes on renal allograft rejection: evidence from a single centre study.

Cytokines are key immune mediators and it has been suggested that cytokine gene polymorphisms affecting expression influence rejection or tolerance. This study sought to examine this hypothesis with the aim of identifying predictive genotype markers for rejection. The study group consisted of 120 consecutive first cadaveric recipient-donor pairs transplanted at a single centre, between 1994 and 1997. PCR utilising sequence-specific primers (SSP) methodology was optimised for genotyping recipient and donor DNA for the following polymorphisms: tumour necrosis factor (TNF) -alpha (-308, G/A), interleukin (IL)-10 (-1082, G/A), IL-4 (-590, C/T), transforming growth factor (TGF) -beta1 (+915, G/C). Recipient-donor pairs were divided into rejectors (n = 28) and non-rejectors (n = 92). Each group was further stratified according to number of rejection episodes and HLA-DR mismatching. Recipient-donor pairs both lacking the IL-4*T allele (recipient low producer/donor low producer) were significantly increased in the rejector group (P = 0.02). Also, the combination of recipient IL-10*A negative/donor IL-10*A positive (recipient high producer/donor low producer), was significantly decreased in multiple rejectors (P = 0.04). No significant associations were detected between TNF-alpha and TGF-beta1, and rejection. This study suggests that the combination of recipient-donor IL-4 and IL-10 genotypes may be important in renal transplantation outcome. The results appear to corroborate the protective role of both of these cytokines, possibly due to their ability to suppress inflammation. However, due to conflicting results from this and other studies, a multi-centre collaborative study may be required to determine whether cytokine genotypes are significant, independent predictors of renal allograft rejection.

Amino Acid Substitution↗

PubMed2001

IL-10 promoter polymorphisms influence tumour development in cutaneous malignant melanoma.

Cutaneous malignant melanoma (CMM) is the most serious cutaneous malignancy. CMM patients often develop an immune response to their tumours. Conflicting evidence suggests that IL-10 may contribute to tumour escape from the immune response, but may also have an anti-tumour effect. To distinguish between these models and to determine whether genotypes associated with differential IL-10 expression confer susceptibility to and/or influence prognosis in CMM, 165 CMM patients and 158 controls were genotyped for IL-10 promoter SNPs by ARMS-PCR. The IL-10--1082 AA low expression genotype was increased in incidence among CMM patients (P = 0.04). In addition, IL-10 genotypes showed significant associations with three of four prognostic indicators examined; IL-10--1082 GG (P = 0.02) and -1082, -819 and -592 compound high expression (P = 0.03) genotypes were associated with horizontal (non-invasive) tumour growth; IL-10--1082 AA low expression genotype was associated with more advanced (Stage II-IV) disease (P = 0.04); finally, the IL-10--1082 AA (P = 0.005) and compound low expression (P = 0.009) genotypes were significantly increased in frequency among patients with thicker primary Vertical growth phase tumours. These results indicate that genotypes associated with high levels of IL-10 expression in vitro are protective in CMM, while low expression genotypes are a risk factor for more advanced/poorer prognosis disease and may confer susceptibility to CMM. Although the influence of IL-10 on melanoma development is likely to be complex, these results support recent findings that IL-10 has an anti-tumour effect in CMM, possibly via inhibition of angiogenesis.

Base Sequence↗

PubMed2001

Modification of T-cell receptor Vbeta repertoire in response to allergen stimulation in peanut allergy.

BACKGROUND: Peanut is one of the most common foods causing allergic reactions and is the most common cause of fatal and near-fatal food-related anaphylaxis. Little is known of the immunologic mechanisms that underlie peanut allergy. OBJECTIVES: In this study we examined clonality of the T-cell response (TCR) to peanut in MHC class II identical, peanut allergy-discordant sibling pairs. METHODS: Four sibling pairs were investigated. The TCR repertoire was analyzed before and after in vitro stimulation of PBMCs with crude peanut or PHA, as control for general/nonspecific reactivity. Eighteen TCR-Vbeta families were examined by flow cytometry. Where significant differences in incidence of particular TCR-Vbeta families were observed, PCR familyspecific cDNA amplification and gene scanning were performed. RESULTS: After stimulation with peanut, no selective expansion of any TCR-Vbeta subpopulation was observed with flow cytometry, in either the peanut-allergic or nonallergic siblings, with the exception of 1 peanut-allergic subject who demonstrated a significant increase of TCR-Vbeta11(+) cells (0.3%-5.9% of the total CD3(+) cells). However, gene scanning revealed predominant single-size PCR products for TCRBV11 in all peanut-allergic subjects after peanut stimulation. TCRBV11 polyclo-nality was observed in allergic and nonallergic subjects before peanut stimulation and in nonallergic subjects after peanut stimulation. In comparison, all subjects, before and after stimulation with peanut, showed polyclonality for TCRBV2. CONCLUSIONS: Our results argue for clonal or oligoclonal TCRs to crude peanut and indicate that changes in the TCRBV11 subpopulation are restricted to peanut-allergic subjects after stimulation with crude peanut allergen.

Allergens↗