Production and characterization of an Fv-clasp of rheumatoid factor, a low-affinity human autoantibody.

Rheumatoid factor (RF) is an autoantibody against IgG that affects autoimmune diseases and inhibits the effectiveness of pharmaceuticals and diagnostic agents. Although RFs derived from various germline genes have been identified, little is known about their molecular recognition mechanisms. In this study, the Fv-clasp format was used to prepare YES8c, an RF. We developed an Escherichia coli secretion expression system capable of producing milligram-scale of YES8c Fv-clasp per 1 L of culture. Although YES8c is an autoantibody with very low affinity, the produced Fv-clasp maintained specific binding to IgG. Interestingly, the molecules prepared by E. coli secretion had a higher affinity than those prepared by refolding. In the structure of the YES8c-Fc complex, the N-terminus of the light chain is close to Fc; therefore, it is suggested that the addition of the N-terminal methionine may cause collisions with Fc, resulting in reduced affinity. Our findings suggest that the Fv-clasp, which provides sufficient stability and a high bacterial yield, is a useful format for studying RFs with very low affinity. Furthermore, the Fv-clasp produced from a secretion expression system, which can properly process the N-terminus, would be suitable for analysis of RFs in which the N-terminus may be involved in interactions.

Anticuerpos antitiroperoxidasa y antitransglutaminasa en familiares de primer grado de personas con diabetes tipo 1 y su relación con algunas características clínicas, bioquímicas e inmunológicas / Antithyroperoxidase and antitransglutaminase antibodies in first degree relatives of type 1 diabetes persons and its relation to some clinical, biochemical and immunological features

Los anticuerpos antitiroperoxidasa (AcTPO) y antitransglutaminasa (ATGt) son útiles marcadores de enfermedad tiroidea autoinmune y enfermedad celíaca, respectivamente. Su presencia en familiares de primer grado de personas con diabetes tipo 1 no se ha descrito en Cuba. Objetivo: determinar las frecuencias de los AcTPO y ATGt en familiares de primer grado de personas con diabetes tipo 1 y su relación con algunas características clínicas, bioquímicas e inmunológicas. En un grupo de 285 sujetos se realizó la medición del AcTPO y en 262 individuos la de ATGt. Se incluyeron casos entre los 2 y 65 años de edad. Se registraron datos sobre edad, sexo, color de la piel, antecedentes personales, historia familiar de obesidad, diabetes tipo 2, enfermedad tiroidea y enfermedad celíaca. Se interrogaron síntomas y exploraron signos clínicos de enfermedad celíaca y enfermedad tiroidea autoinmune. Se determinó glucemia, insulinemia, AcTPO, ATGt y autoanticuerpos asociados a diabetes tipo 1 (AGAD y AIA-2), así como la resistencia a la insulina mediante el índice HOMA-IR. RESULTADOS: las frecuencias de AcTPO y ATGt positivos fueron 5,3 y 1,9 por ciento, respectivamente. La historia familiar de enfermedad tiroidea, el temblor muscular fino y el exoftalmos se relacionaron con la presencia de AcTPO. Malabsorción intestinal, diarrea persistente, dolor abdominal recurrente y antecedente personal de hepatopatía se asociaron con la presencia de ATGt. Se encontró asociación entre los ATGt y el AIA-2. La resistencia a la insulina no se asoció con la presencia de AcTPO ni de ATGt. En los familiares de primer grado de personas con diabetes tipo 1 las frecuencias de AcTPO y ATGt son bajas. Algunos antecedentes, síntomas y signos vinculados con enfermedad celíaca y enfermedad tiroidea autoinmune pueden ser indicadores prácticos previos a la indicación de estos autoanticuerpos(AU)

The antithyroperoxidase (TPOAb) and antitransglutaminase (tTGAb) antibodies are useful markers of autoimmune thyroid disease and celiac disease, respectively. Its presence in first-degree relatives of type 1 diabetes patients has not been described in Cuba. Objetive: to determine the TPOAb and tTGAb frequencies in first-degree relatives of type 1 diabetes patients and its relation to some clinical, biochemical and immunological features. In a group of 285 subjects we measured TPOAb and in 262 subjects we measured tTGAb. The cases included aged between 2 and 65. Data were registered on age, sex, skin color, personal backgrounds, and a family history of obesity, type 2 diabetes, thyroid disease and celiac disease. Symptoms were look for and clinical signs of celiac disease and autoimmune thyroid disease were explored. Fasting glucose, fasting insulin, TPOAb, tTGAb and type 1 diabetes associated autoantibodies (AGAD and AIA-2) were determined as well as the insulin resistance according the HOMA-IR index. RESULTS: the frequencies of positive TPOAb and tTGAb were of 5,3 and 1,9 percent, respectively. The family history of thyroid disease, slight muscular tremor and exophthalmos are related to presence of TPOAb. Intestinal malabsorption, persistent diarrhea, recurrent abdominal pain and personal background of liver disease were associated with presence of tTGAb. There was an association between tTGAb and AIA-2. Insulin resistance was not associated with the presence of both antibodies. In first-degree relatives of type 1 diabetes patients, frequencies of TPOAb and tTGAb are low. Some backgrounds, symptoms and signs linked to celiac disease and autoimmune thyroid disease may be practical indicators previous to perform these autoantibodies(AU)

Transition from Pemphigus Foliaceus to Pemphigus Vulgaris: Case Report with Literature Review

The transition between the main subtypes of pemphigus, pemphigus vulgaris (PV), and pemphigus foliaceus (PF) has rarely been reported. Moreover, the development of PV in a patient with PF is much more unusual than that of PF in a patient with PV. We report a 48-year-old man who presented with cutaneous lesions showing the typical clinical and histological features of PF. Five years later, his skin lesions became extensive and he developed oral erosions. His condition did not respond well to steroids and azathioprine. Histological examination of a vesicle disclosed suprabasal acantholysis in contrast to the subcorneal acantholysis discovered upon initial histological evaluation. Indirect immunofluorescence revealed IgG antikeratinocyte cell surface antibodies at a titer of 1:640. The titer was 1:160 at initial diagnosis. Upon immunoblotting, the patient's serum reacted with 130 kiloDalton (kDa) and 160 kDa proteins, suggesting desmoglein (Dsg) 3 and 1, respectively. We herein report an unusual case of PV that developed from PF during the disease's flare-up.

Circulating Autoantibodies in Patients with Aspirin-intolerant Asthma: An Epiphenomenon Related to Airway Inflammation

Several studies have suggested the involvement of an autoimmune mechanism in aspirin (ASA)-intolerant asthma. To test this hypothesis, we measured the levels of circulating autoantibodies, such as IgG and IgA to tissue transglutaminase (TGase), IgG to cytokeratins (CKs) 8, 18, and 19, Clq-binding immune complex (CIC), and antinuclear antibody (ANA), in the sera of 79 patients with ASA-intolerant asthma (Group I) and those of two control groups, consisting of 61 patients with ASA-tolerant asthma (Group II) and 88 healthy control subjects (Group III) by means of ELISA. Significantly higher prevalences of IgG antibodies to CK18 (13.9%) and CK19 (17.7%) were noted in Group I, as compared with Group III (p<0.05 for all) not with Group II. Regarding the prevalences of other autoantibodies, the levels of ANA (1.3%), IgG to TGase (3.8%), and CIC (24.7%) in Group I were not significantly different from those in Groups II and III. Significant correlations were found between positivities for the anti-CK18 and anti-CK19 autoantibodies and the PC20 methacholine values in the analysis of asthma Groups I and II vs. normal controls, (p=0.001 and p=0.003, respectively). Further studies are needed to explore the potential involvement of an autoantibody-mediated mechanism in the clinical manifestation of bronchial asthma.