A partir de isolados de campo de P. falciparum de pacientes sintomáticos e assintomáticos de uma mesma área endêmica brasileira, clonamos fragmentos de genes surf e dos genes das proteínas do merozoíto AMA1 e das famílias MSP e EBL. Expressamos todas as sequências diferentes encontradas fusionadas a GST. Por ELISA, testamos a positividade para IgG dos plasmas das mesmas amostras de sangue e identificamos as subclasses de IgG nos plasmas mais reativos e a duração da resposta de IgG em um subgrupo de plasmas. A odds ratio conferida pela resposta humoral contra MSP5, MSP9 e SURFIN 13.1 mostrou 9x menos chances para os dois primeiros e 3,5x menos chances para o terceiro para a presença de sintomas, através da análise de tabelas de contingência. A odds ratio conferida pela resposta humoral mais intensa a MSP5 e EBA175 aponta respectivamente, 9,4x e 5,7x mais chances de desenvolvimento do perfil assintomático, por regressão logística. Paralelamente, verificamos por RT-qPCR que pode ocorrer switching transcricional e talvez exclusão alélica na expressão de genes surf. / Using field P. falciparum isolates present in the blood of symptomatic and asymptomatic patients from the same endemic Brazilian area, we cloned and expressed all different sequences of surf genes and those encoding merozoite antigens AMA1, MSP1-10 and members of the EBL protein family as GST fusion peptides. We identified plasmas positive for specific IgG and their subclasses in the most reactive plasmas and the longevity of the response in a lot of plasmas by ELISA. The odds ratio conferred by antibodies against MSP5, MSP9 and SURFIN 13.1 pointed to 9x fewer chances of the first two and 3,5x fewer chances of the last for presence of malaria symptoms by cross tab analysis. The odds ratio conferred by the higher quantity of antibodies against MSP5 and EBA175 pointed to 9,4x and 5,7x higher chances for development of an asymptomatic profile by logistic regression. In parallel, transcription analysis of surf genes in the P. falciparum strain 3D7 verified by RT-qPCR pointed to a mechanism reminiscent of allelic exclusion.

There are multiple immune mechanisms identified for persistence of hepatitis B virus (HBV) infection. This thesis considers the vital role that inhibitory receptors play in contributing to impairment of the adaptive immune system in chronic hepatitis B (CHB), and the potential role they play in the innate immune system, focusing on the inhibitory receptor leucocyte-associated immunoglobulin-like receptor (LAIR)-1. The unique aspect of this work is that for the first time LAIR-1 expression has been investigated on natural killer (NK) cells in CHB. Our striking findings of increased LAIR-1 expression on peripheral NK cells in CHB and an inverse correlation between expression and effector function suggest this inhibitory receptor could have a potential role in exhaustion of NK cells in CHB. We therefore additionally explored the expression of LAIR-1 on circulating NK cells from patients with hepatocellular carcinoma (HCC) and non-alcoholic fatty liver disease (NAFLD). The particular relevance of LAIR-1 to liver disease is that one of its major ligands is collagen. We demonstrated a downregulation of LAIR-1 expression on intrahepatic NK cells, which we postulate might occur following repetitive engagement with abundant collagen within the liver. In line with this, intrahepatic NK cells with a liver-resident (CXCR6+) phenotype had even lower LAIR-1 expression than liver infiltrating (non-resident, CXCR6-) NK cells. Furthermore, preliminary experiments display attenuation of the cytotoxic degranulation capacity (CD107a) by circulating NK cells from CHB patients upon exposure to plate-bound collagen. We demonstrate differential expression of LAIR-1 on NK cells in viral hepatitis, HCC and NAFLD and between peripheral and intrahepatic NK cells. Preliminary experiments demonstrate a role in inhibiting NK cell function suggesting this as a novel therapeutic target to harness the capacity of NK cells to control chronic infection and cancer.

O câncer colorretal (CCR) pode ocorrer em qualquer parte do cólon ou do reto e representa o terceiro câncer mais comum no mundo em ambos os sexos. As células Natural Killer (NK) fazem parte do sistema imune inato reconhecendo moléculas de HLA de classe I em células alvo, através de seus receptores de membrana killer cell immunoglobulin-like receptors (KIR). O objetivo deste estudo foi avaliar a associação entre os genes KIR e os ligantes HLA em pacientes com câncer colorretal e controles saudáveis. Examinamos o polimorfismo de 16 genes KIR e seus ligantes HLA em 154 pacientes caucasóides com CCR e 216 controles saudáveis pela técnica de PCR-SSO e PCR-SSP. Quando comparamos os dois grupos, não foram encontradas diferenças significativas para os ligantes HLA e os genes KIR após correção de Bonferroni. Entretanto, o grupo de genótipos Bx (heterozigoto e homozigoto para o haplótipo B) foi mais frequente nos controles, quando comparados com os pacientes. Estes achados sugerem que altos níveis de ativação de sinais KIR aparecem como proteção para o câncer colorretal. / Colorectal cancer (CRC) can occur anywhere in the colon or rectum and represents the third most common cancer in the world in both sexes. Natural killer cells (NK) are part of the innate immune system recognizing class I HLA molecules on target cells through their membrane receptors, called killer cell immunoglobulin-like receptors (KIR). The aim of our study was to evaluate the association between the KIR genes and HLA ligands in patients with colorectal cancer and healthy controls. We examined the polymorphism of 16 KIR genes and their HLA ligands in 154 caucasoid CRC patients and 216 healthy controls by PCR-SSO and PCR-SSP. When both groups were compared, no significant differences were found for HLA ligands and KIR genes after Bonferroni correction. However, the Bx group genotypes (heterozygous and homozygous for the haplotype B) were more frequent in controls, when compared with patients. These findings suggest that individuals with Bx genotypes could have some protection to colorectal cancer. These findings suggest that higher levels of activating KIR signals appear as protective to colorectal cancer.

Objetivo: Comparar as relações de custo-efetividade de duas terapias, Imunoglubulina Intravenosa (IgIV) e Plasmaferese (PE), no tratamento da Síndrome de Guillain-Barré sob a perspectiva do sistema público (SUS). O objetivo secundário foi avaliar a adesão às recomendações da Comissão de Medicamentos do HCPA Métodos: estudo transversal com análise econômica de pacientes tratados por Síndrome de Guillain-Barré no período de junho de 2003 a junho de 2008 no Hospital de Clínicas de Porto Alegre (HCPA). Foi realizada análise de custo-efetividade do emprego de IgIV e de PE nestes pacientes, pelo método de minimização de custos, considerando-se somente os custos diretos sanitários, fornecidos pelo sistema gerencial da instituição . Foram excluídos os pacientes que usaram outro tipo de tratamento associado ou isolado. Coletaram-se os dados através da revisão dos prontuários. A gravidade da doença na internação foi classificada como: doença leve, quando caminhar foi possível; doença moderada, quando caminhar foi impossível; doença grave, quando os pacientes necessitaram de ventilação assistida. A incapacidade na alta foi estabelecida pela escala de sete pontos de Hughes. A adesão às recomendações da Comissão de Medicamentos do HCPA, objetivo secundário, foi avaliada através da dose e o esquema de prescrição da IgIV. Resultados: Vinte e cinco participantes (2 a 70 anos) foram incluídos no estudo, cinco tratados com PE, empregando-se Albumina Humana como substituto do plasma, e 20 tratados com IgIV. O custo total do tratamento de um paciente com PE foi R$10.603,88 (± 2.978,12) e o de um que recebeu IgIV foi R$ 32.103,00 (± 21.454,24). O custo total da internação foi de R$45.027,14 (± 32.750,45) para os tratados com PE e de R$ 60.844,28 (±48.590,52) para os que receberam IgIV. Em relação ao desfecho clínico principal, melhora na escala de incapacidade de sete pontos, após o tratamento com uma das alternativas escolhida, a mediana dos pacientes que internaram com grau de gravidade 3 e que foram tratados com PE foi igual a dos que receberam IgIV. Em relação à permanência hospitalar, permanência em UTI e dias de Ventilação Mecânica, não houve diferença estatisticamente significativa entre os dois tratamentos. Conclusões: Quando comparados os custos médios das duas opções terapêuticas, uma delas aparece claramente com menor custo. Quando comparados os desfechos, após o emprego de cada opção terapêutica, estes não revelam diferença. Concluímos que, no HCPA, a opção pelo procedimento Plasmaferese é mais custo efetiva do que o emprego da IgIV. / Objectives: To compare the cost-effectiveness of two distinct therapies, Intravenous Immunoglobulin (IVIg) and Plasma Exchange (PE) in the treatment of Guillain-Barré Syndrome, concerning the public health care system. Compliance to the guidelines of the Pharmacy and Therapeutics Committee of the Hospital de Clínicas de Porto Alegre was a secondary objective. Methods: A cross-sectional, economical analysis was conducted, including patients treated for GBS in the period from June, 2003 through June, 2008 in Hospital de Clínicas de Porto Alegre (HCPA). The cost-effectiveness of the use of IVIg and PE in such patients was studied through the cost minimization method, considering direct medical costs only (2008 currency), yield by the management of the institution. Patients receiving treatments other than PE or IVIg were excluded. Data were collected by chart reviews. Severity of disease on admittance was classified as follows: mild disease, when the patient was able to walk; moderate disease, when the patient was unable to walk, and severe disease, when assisted ventilation was required. Disability on discharge was established by the 7-point scale of Hughes. Compliance to the guidelines of the Pharmacy and Therapeutics Committee was evaluated through the dose and prescription scheme of IVIg. Results: Twenty-five participants (2 to 70 years of age) were included in the study, 5 were submitted to treatment with PE, using human albumin as replacement for plasma, and 20 were treated with IVIg. The total treatment cost for PE in a single patient was US$6,058.85 (±1,701.78 SD), and the same expense for IVIg was US$18,344.57 (± 12,259.56 SD) (p = 0.035). Total inpatient cost was US$25,729.79 (± 18,714.54 SD) in the PE group, and US$34,768.16 (±27,766.01 SD) (p=0.530) in the IVIg group. The main clinical outcome was improvement in the 7-point disability grade scale. The median of that measure in patients admitted with a severity grade 3 treated either with PE and IVIg was the same. Secondary outcomes, such as in-hospital stay, ICU stay, and number of days on mechanical ventilation revealed no statistically significant difference between treatments. Conclusions: As the mean expenses of both therapeutic options are compared, one clearly stands-out as less onerous. Clinical outcomes, when compared, reveal no statistical difference after each treatment. We concluded that, in HCPA, plasma exchange is more cost-effective than intravenous immunoglobulin.

A imunodeficiência comum variável (ICV) é uma síndrome heterogênea caracterizada por hipogamaglobulinemia e infecções bacterianas de repetição. As doenças obstrutivas, como a asma, estão presentes em aproximadamente 50% dos pacientes. Os sintomas decorrentes de infecções respiratórias de repetição podem mascarar os sintomas de alergia respiratória. A asma tem alta prevalência no mundo e é observada em aproximadamente 10% da população brasileira. Embora muitos pacientes com ICV apresentem história clínica sugestiva de rinite e/ou asma alérgicas, a participação da atopia não está bem esclarecida e freqüentemente os níveis de IgE total e/ou IgE específica estão baixos. Muitos autores estudam a produção de IgE local e uma correlação entre a concentração de IgE nos fluidos corporais e no soro existe. Os objetivos deste estudo são avaliar a função pulmonar em pacientes com ICV através de: espirometria, provocação brônquica com histamina e com alérgeno; investigar o diagnóstico de asma em pacientes com ICV e realizar a investigação in vivo e in vitro da IgE em pacientes com ICV. Este estudo incluiu 62 pacientes que estavam em acompanhamento ambulatorial no Serviço de Imunologia Clínica e Alergia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. A função pulmonar foi avaliada pela espirometria e pela provocação brônquica com histamina antes e após uma provocação brônquica com Dermatophagoides pteronyssinus (Der p) e a investigação da IgE específica para aeroalérgenos através de teste epicutâneo e avaliação da IgE sérica específica usando ImmunoCAPTM. Vinte e nove (46,7%) tinham história clínica de sugestiva de asma e em relação à atopia, 27 (43,5%) tinham história sugestiva de atopia. Uma associação de asma e atopia no mesmo paciente foi encontrada em 18 pacientes (29%). Nós comparamos o grupo sugestivo de asma alérgica com os outros pacientes pacientes com rinite alérgica ou não-alérgica, asma não-alérgica e pacientes sem sintomas respiratórios. A maioria dos pacientes apresentou níveis séricos de IgE total indetectáveis. Somente dois pacientes apresentaram resultado positivo para IgE específica pelo teste epicutâneo e in vitro. Sessenta e um pacientes realizaram espirometria. Destes, 25 pacientes (41%) apresentaram resultado normal, 29 (47,5%) apresentaram distúrbio ventilatório obstrutivo e 7 (11,5%) apresentaram resultados sugestivos de distúrbio ventilatório restritivo. As provocações brônquicas foram realizadas em 15 pacientes. A provocação brônquica com histamina foi considerada positiva em 3 pacientes com história positiva para asma. Em relação à provocação brônquica com Der p, nenhum paciente apresentou resposta imediata positiva. Entretanto, quando a segunda provocação brônquica com histamina foi realizada (pós-Der p), quatro dos 5 pacientes com história sugestiva de asma alérgica apresentaram resultado positivo, com diminuição de PC20 em relação à primeira provocação vi brônquica com histamina. Uma diferença estatística foi observada nos resultados entre o grupo sugestivo de asma alérgica e os pacientes sem asma alérgica. Ao final do estudo, a asma foi confirmada em 9 pacientes com ICV (14,5%), a atopia foi confirmada em 6 pacientes com ICV (9,7%) e a asma alérgica foi confirmada em 4 pacientes com ICV (6,5%), que correspondeu a 22,2% dos 18 pacientes com suspeita de asma alérgica / Common variable immunodeficiency (CVID) is a heterogenous immunodeficiency syndrome characterized by hypogammaglobulinemia, and recurrent bacterial infections. Obstructive diseases as asthma are present in approximately 50 % of patients. Symptoms due to recurrent respiratory pyogenic infections may mask respiratory allergic symptoms. Asthma has high worldwide prevalence and is observed in approximately 10 % of Brazilian population. Although a number of patients with CVID report a clinical history suggestive of allergic symptoms, the role of atopy is not well established in these individuals; and frequently levels of total IgE and/or specific IgE are low. Local IgE production has been studied and a correlation between IgE concentration in body fluids and serum exists. The objectives of this study are evaluation of pulmonary function in patients with CVID through: spirometry, bronchial challenge with histamine, and with allergen; investigate asthma diagnosis in patients with CVID; perform in vivo and in vitro investigation of IgE in patients with CVID. This study included sixty-two patients, who were being followed at the Service of Clinical Immunology and Allergy of the Hospital das Clínicas of the University of São Paulo Medical School. Pulmonary function was assessed using spirometry and bronchial challenge with histamine before and after a bronchial challenge with Dermatophagoides pteronyssinus (Der p), and investigation of specific IgE for aeroallergens with skin prick test and serum specific IgE evaluation using ImmunoCAPTM. Twenty-nine (46.7 %) had clinical history suggestive of asthma, and in regards to atopy, twenty-seven patients (43.5%) reported atopy suggestive history. An association of asthma and atopy in the same patient was observed in eighteen (29 %) participants. We compared the group of allergic asthma with the other patients patients with allergic or non-allergic rhinitis, non-allergic asthma, and patients without respiratory. Most patients had undetectable levels of total IgE concentration in serum. Only two patients had positive results for specific IgE by prick test and in vitro investigation. All patients, except one, underwent spirometry test for lung function evaluation. Of the sixty-one patients, twenty-five (41 %) had normal spirometry results, twenty-nine (47.5 %) had Obstructive Ventilatory Defect, and seven (11.5 %) had results suggestive of Restrictive Ventilatory Defect. Bronchial challenges were performed in fifteen patients. Bronchial challenge with histamine was considered positive in three patients with a positive history of asthma. Regarding to bronchial challenge with Der p, none presented immediate positive response. However, when the second nonspecific bronchial provocation with histamine was performed (post-Der p), four of the five patients with a history of allergic asthma had positive test results, with lower PC20 than in the first non-specific bronchial provocation with histamine. A statistical difference was noticed in the test results of the group suggestive for allergic asthma and the patients without allergic asthma. viii At the end of this study, asthma had been confirmed in 9 patients with CVID (14.5%), atopy had been confirmed in 6 patients with CVID (9.7%), and allergic asthma had been confirmed in 4 patients with CVID (6.5%), which corresponded to 22.2% of the 18 patients suspected of allergic asthma

Ebola virus (EBOV) is a member of the Filoviridae family of highly pathogenic viruses that cause severe hemorrhagic fever and is the causative agent of the 2014 West Africa outbreak. Currently, there are no approved filovirus vaccines or treatments to combat these sporadic and deadly epidemics. One target for EBOV antiviral therapy is to block viral entry into host cells. Recently, phosphatidylserine (PtdSer) receptors, primarily known for their involvement in the clearance of dying cells, were shown to mediate entry of enveloped viruses including filoviruses. The PtdSer receptors, T-cell immunoglobulin mucin domain-1 (TIM-1) and family member TIM-4, serve as filovirus receptors, significantly enhancing EBOV entry. TIM-dependent virus uptake occurs via apoptotic mimicry by binding to PtdSer on the surface of virions through a conserved PtdSer binding pocket within the amino terminal IgV domain. TIM-4 is expressed on antigen presenting cells (APCs), including macrophages and dendritic cells (DCs), which are critical in early EBOV infection. My studies are the first to define the molecular details of virion/TIM-4 interactions and establish the importance of TIM-4 for EBOV infection of murine resident peritoneal macrophages. In addition, previous work has utilized only in vitro models to establish the importance of the TIM proteins in EBOV entry. My studies are the first to demonstrate the importance of TIM-1 and TIM-4 for in vivo EBOV pathogenesis and to confirm them as relevant targets of future filovirus therapeutics. Macrophage phenotypes can vary greatly depending upon chemokine and cytokine signals from their microenvironment. Historically, macrophages have been classified into two major subgroups: classically activated macrophages (M1) and alternatively activated macrophages (M2). Macrophages are a critical early target of EBOV infection and my work primarily focused on interferon gamma-stimulated (M1) macrophages since this treatment profoundly inhibited EBOV infection of human and murine macrophages. Interferon gamma treatment blocked EBOV replication in macrophages, reducing viral RNA levels in a manner similar to that observed when cultures were treated with the protein synthesis inhibitor, cycloheximide. Microarray studies with interferon gamma-treated human macrophages identified more than 160 interferon-stimulated genes. Ectopic expression of a select group of these genes inhibited EBOV infection. These studies provide new potential avenues for antiviral targeting as these genes that have not previously appreciated to inhibit infection of negative strand RNA viruses including EBOV. In addition and most exciting, using MA-EBOV, we found that murine interferon gamma, when administered either 24 hours before or after infection, protects lethally challenged mice and significantly reduces morbidity. Our findings suggest that interferon gamma, an FDA-approved drug, may serve as a novel and effective prophylactic or treatment option.

<p>Immunoglobulin E (IgE) is an important mediator in atopic allergies. This thesis describes the development of a therapeutic vaccine against IgE and its effects in rats and dogs. The development of an assay to determine IgE levels in dogs, and the finding of a chromosome region in rats that affects IgE levels are also reported. </p><p>The vaccine is a chimeric molecule consisting of the constant domains Cε2, Cε3 and Cε4 from IgE. The target domain of the vaccine is the Cε3 domain in the recipient species, which is the domain directly involved in receptor binding, while the flanking regions, Cε2 and Cε4, are from a distantly related mammal. In rats, the vaccine induced an immune response against circulating IgE, which decreased IgE levels by 90% and substantially reduced their allergic symptoms. Further, the effects of adjuvants in rats and dogs were evaluated, and when co-administered with the vaccine certain adjuvants were shown to increase the immune response against IgE. Mineral-oils were the most potent adjuvants in inducing a response against IgE, but metabolizable oils spiked with immunostimulatory substances were also efficient. </p><p>It was also shown that the therapeutic vaccine could induce a decrease in IgE levels in adult dogs, even though their initial levels were exceptionally high compared with humans. The IgE levels in 76 dogs ranged between 1 and 41 μg/ml while humans normally have around 150 ng/ml. However, the high IgE levels did not correlate to any specific breed, nor did they distinguish between dogs that were diagnosed as healthy and those suffering from atopic eczema, autoimmunity or skin parasites. </p><p>Regulation of total IgE levels probably involves many genes. In the final phase of the study, one candidate locus known to be involved in arthritis susceptibility in rats was investigated, and was found also to affect IgE levels.</p>

<p>B cell lymphoma (BCL) comprises a biologically and clinically heterogeneous group of tumors deriving from different stages of B cell development. The immunoglobulin (Ig) variable heavy chain (V_H) gene rearrangement is unique for each BCL and can be used to reveal cellular origin, to study signs of antigen selection and to quantify tumor cell load.</p><p>The normal counterpart of mantle cell lymphoma (MCL) has been postulated to be a naïve B cell and in hairy cell leukemia (HCL) it is considered to be a post-germinal centre B cell. We analyzed the V_H gene rearrangements in 110 MCLs and 32 HCLs by PCR amplification and sequencing. Most MCLs (84%) displayed V_H genes lacking somatic hypermutation (SHM), thus correlating to a naïve cell origin, whereas a subgroup (16%) showed SHM, implying derivation from a more differentiated B cell. In HCL, a majority of cases (84%) displayed SHM with signs of intraclonal heterogeneity and 16% had unmutated V_H genes, thus questioning the cell of origin in HCL. Biased usage of particular V_H genes was detected in both HCL (V_H3-30) and MCL (V_H3-21 and V_H4-34), which indicates that antigen selection may be involved in lymphoma development. Furthermore, V_H3-21⁺ MCLs showed a highly restricted V_λ3-19 gene use and they also had a superior outcome compared to other MCLs.</p><p>Rearrangement analysis of 67 V_H3-21⁺ chronic lymphocytic leukemia (CLL) cases from three different countries verified, regardless of geographical origin, the short and highly homologous complementarity determining region 3s and the strikingly biased usage of the V_λ2-14 gene (75%), as previously reported in CLL. This further supports that antigen selection by a common antigenic epitope may have occurred in V_H3-21⁺ CLLs. </p><p>In an autologous transplantation study of 30 multiple myeloma patients, we quantified the tumor content in the autografts before and after stem cell selection using clone-specific PCR. We conclude that stem cell selection reduced the number of clonal cells linearly, but purging could not totally eliminate the tumor cells from the graft, thus increasing the risk of a relapse.</p><p>Altogether, our data allowed us to define new BCL subsets and to gain insights into the potential role of antigen selection in BCL development as well as the monitoring of tumor cell load using Ig gene rearrangements analysis. </p>

<p>Malt lymphoma is a malignant disease that can arise in a variety of extra nodal sites. Previous studies indicate that tumour arise from more mature B-cells.</p><p>Our purpose was to examine the presence of clonality and somatic hypermutation of immunoglobulin (IgVн) of MALT lymphomas.</p><p>Paraffin-embedded tumour samples from13 MALT lymphoma were subjected to rearrangement analysis, by using PCR, heteroduplex gels and sequence analysis.</p><p>Successful amplification was seen in 10/13 cases and sequences of IgVн genes were obtained in 6/13, all of them were mutated. The percentage of mutation compared to germline sequences was 1,1% to 8,6% monoclonal rearrangemang. It was demonstrated that 5 of 7 clones were derived from the Vн3 family, 2 from Vн1 and 1 from the Vн 4 family.</p>

Immunoglobulin E (IgE) is an important mediator in atopic allergies. This thesis describes the development of a therapeutic vaccine against IgE and its effects in rats and dogs. The development of an assay to determine IgE levels in dogs, and the finding of a chromosome region in rats that affects IgE levels are also reported. The vaccine is a chimeric molecule consisting of the constant domains Cε2, Cε3 and Cε4 from IgE. The target domain of the vaccine is the Cε3 domain in the recipient species, which is the domain directly involved in receptor binding, while the flanking regions, Cε2 and Cε4, are from a distantly related mammal. In rats, the vaccine induced an immune response against circulating IgE, which decreased IgE levels by 90% and substantially reduced their allergic symptoms. Further, the effects of adjuvants in rats and dogs were evaluated, and when co-administered with the vaccine certain adjuvants were shown to increase the immune response against IgE. Mineral-oils were the most potent adjuvants in inducing a response against IgE, but metabolizable oils spiked with immunostimulatory substances were also efficient. It was also shown that the therapeutic vaccine could induce a decrease in IgE levels in adult dogs, even though their initial levels were exceptionally high compared with humans. The IgE levels in 76 dogs ranged between 1 and 41 μg/ml while humans normally have around 150 ng/ml. However, the high IgE levels did not correlate to any specific breed, nor did they distinguish between dogs that were diagnosed as healthy and those suffering from atopic eczema, autoimmunity or skin parasites. Regulation of total IgE levels probably involves many genes. In the final phase of the study, one candidate locus known to be involved in arthritis susceptibility in rats was investigated, and was found also to affect IgE levels.