Israel Medical Association Journal

The formerly prevalent concept that intact autoantibodies could not penetrate into viable cells has been defeated by a large amount of experimental findings and clinical observations that indicate otherwise. The penetration of autoantibodies into living cells seems to participate in the pathogenesis of diverse autoimmune diseases, but it may also play a physiological role in healthy individuals. Although the fine mechanisms of the phenomenom remain to be elucidated, the potential use of penetrating autoantibodies as vectors to deliver molecules into cells, with diverse therapeutic purposes, has gained growing interest during the last few years.

The future promises good news for the treatment of systemic lupus erythematosus, some of which can already be foreseen. Increased knowledge on genes that participate in the predis­position, pathogenesis, pharmacogenetics of, and protection against this disease may permit intervention at this level. Also, better understanding about the role of sex hormones has allowed trials of weak androgens or prolactin inhibitors. New immunomodulators or i mmunosuppresors may enable more precise treatment at the immunoregulatory level, and greater knowledge on the disturbance of circuits has already provided hints and even allowed trials of anti-interleukin-10 antibodies, an IL-10 decreasing agent, tolerance-induction strategies or intervention at the level of T cell co-stimulation, as well as immune ablation with subsequent stem cell transplantation. Autoantibodies can be removed, controlled by means of anti­idiotypes, which are blocked from reaching their target antigen or uncoupled from the tissues they have reached. All these treatment strategies will gradually become decanted in order to achieve the optimal treatment of SEE, which may turn out to be its cure.

Background: Anti-endomysial antibodies are sensitive and specific markers for celiac disease. This antibody has recently been identified as an antibody to tissue transglutaminase, an enzyme that cross-links and stabilizes extracellular matrix proteins.

Objectives: To evaluate the clinical usefulness of an enzyme-linked immunoassay for anti-transglutaminase antibodies, and to compare the results with those of AEA, the current gold standard serological test for celiac disease.

Methods: Serum samples were collected from 33 patients with biopsy-proven celiac disease and AEA tests were performed. Control samples for anti-transglutaminase were obtained from 155 patients. An ELISA test for immunoglobulin A anti-transglutaminase utilizing guinea pig liver transglutaminase was developed and performed on all sera.  Cutoff values for the test were performed using logistic regression and receiver operating curves analysis.

Results: An optical density cutoff value of 0.34 was established for the assay. The mean value was 0.18±0.19 optical density for controls, and 1.65±1.14 for patients with celiac disease (P<0.001). Sensitivity and specificity of the assay were both 90%, while AEA had a sensitivity and specificity of 100% and 94%, respectively.

Conclusions: A tissue transglutaminase-based ELISA test is both sensitive and specific for  detection of celiac disease.

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AEA = anti-endomysial antibody

Background: According to studies from different countries, the prevalence of natural rubber latex sensitization in healthcare workers ranges from 2.9 to 17%.

Objective: To estimate the prevalence of NRL-specific IgE antibodies in healthcare workers in Israel.

Methods: Three hundred healthcare workers, mostly from a major pediatric tertiary care facility, and 15 non-healthcare workers completed a questionnaire on signs and symptoms of NRL allergy and other respiratory and food allergies. NRL-specific IgE antibodies were assayed with the DPC AlaSTAT-ELISA method.

Results: Seventy of the 300 workers (23.3%) reported symptoms of NRL allergy: hand eczema and pruritus in 63, upper respiratory tract and ocular symptoms in 10, shortness of breath in 2, and generalized rash in 6. None had anaphylaxis due to latex exposure. There was a significant correlation of symptoms of NRL allergy with atopy and job category (nurses, laboratory technicians, nurse assistants and dental medicine workers), but not with gender, age, or years of employment. The in vitro tests for specific IgE antibodies against NRL were positive (≥0.70 IU/ml) in five workers (1.66%).

Conclusions: This is the first study of the prevalence of NRL-specific IgE antibodies in healthcare workers in Israel. Our 1.66% sensitization rate is much lower than that reported for healthcare workers in other countries. This difference may be due to our inclusion of a study population with a relatively low exposure to latex gloves (pediatricians compared to surgeons). Further studies are needed in this and other high risk populations in Israel.  

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NRL = natural rubber latex

Background: There is an increasing number of reports of pertussis among older children and adults. The development and licensure of an acellular pertussis vaccine offer the possibility of adult vaccination against the disease. Information on immunity to pertussis in this age group is needed before any vaccination policy can be considered.

Objectives: To study the seroepidemiology of pertussis antibodies in a random sample of adolescents.

Methods: Serum IgG antibodies to whole-cell lysate of Bordetella pertussis were measured by enzyme-linked immunosorbent assay in sera of 533 Israeli military recruits aged 17–18 years. Epidemiologic variables were collected by a questionnaire and analyzed for correlation with pertussis antibodies.  

Results: Of the sera tested 58.6% were positive for pertussis IgG antibodies, while 35.4% were negative and 6% were borderline. The seropositivity rate was significantly higher among females and non-smokers than among males and smokers. Serum samples of subjects found negative to Bordetella pertussis on recruitment were tested again, using the same ELISA assay, 2–3 years later.  Seroconversion during the 3 year military service was detected in 12.5% of 40 subjects. Using the pertussis toxin as the antigen in a subsample of 160 sera, the seroprevalence was lower than that detected by the whole-cell lysate on the same sera (45% vs. 58%).

Conclusions: A significant part of the adolescent population in Israel has low titer of serum IgG antibodies to the multiple antigens of B. pertussis. The relatively low concentration of anti-pertussis antibodies, together with the serological evidence of exposure to the disease indicates that booster immunization with the acellular pertussis vaccine of military recruits should be considered after more information on the incidence of clinical cases of pertussis will be available.

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ELISA = enzyme-linked immunosorbent assay

Background: Previous studies have published controversial results regarding a connection between Helicobacter pylori infection and colorectal cancer. One possible mechanism is increased gastrin secretion in subjects infected with H. pylori, insofar as gastrin is known to be a trophic factor for the colonic mucosa.

Objectives: To investigate a possible role of gastrin secretion in H. pylori infection associated with colorectal cancer, and determine whether H. pylori infection is a factor in this disease.

Methods: The serum gastrin levels and the presence of H. pylori IgG antibodies were measured in 51 colorectal cancer patients and 51 control subjects. The cancer patients were also tested for carcinoembryonic antigen and CA 19-9.

Results: H. pylori IgG antibodies were found in the serum of 41 (80.4%) of the cancer patients compared to 32 (62.7%) of the control subjects (P=0.05). A significant correlation was found between CA 19-9 (γ=0.3432, n=49, P=0.01) and seropositive H. pylori IgG antibodies in the serum of the cancer patients (odds ratio 2.43, and 95% confidence limit 0.99-5.95), but none between CEA and H. pylori IgG antibodies nor between the serum gastrin level and the presence of colorectal cancer.

Conclusions: The results of this study indicate a significant association between seropositive H. pylori IgG antibodies and elevated CA 19-9 in colorectal cancer patients, but no correlation between the serum gastrin level and the presence of this cancer. H. pylori seropositivity is more prevalent in patients with colorectal cancer.
 

Objectives: To evaluate the association between chronic infection with C. pneumoniae, as measured by a high titer of IgG antibody, and CAD. Our study was designed to explore the relationship between seropositivity to C. pneumoniae and serious coronary events, and to assess whether or not there may be an additional association between established cardiovascular factors and infection with this organism.

Methods: The serum of 130 patients with proven CAD was tested for the presence of IgG antibodies to C. pneumoniae using an ELISA test. A titer ≤1:64 using the microinfluorescence method, the recognized "gold standard," correlates with a positive result when using the ELISA method. The mean age was 57 (40-65 years). The patients, 82% male and 18% female, had either myocardial infarction (n=109) or unstable angina (n=21) 6 months before the investigation (range 3-24 months). The serum for the control group was obtained from 98 blood donors from the same area matched for age 52 (40-58 years) and sex. The donors had no known cardiac history.

Results: In the CAD group 75% of patients were positive for C. pneumoniae compared to 33% in the control group (P=0.001). No increased correlation could be demonstrated between traditional risk factors and C. pneumoniae infection, except in those patients with diabetes mellitus. We found a lower prevalence of IgG antibody to C. pneumoniae in the diabetes subgroup than in other subgroups (P<0.006), but a higher prevalence than in the control group.

Conclusions: We demonstrated a more than twofold increase in seropositivity to C. pneumoniae among patients suffering serious coronary events, and this trend was independent of gender, age or ethnic group. These findings suggest that chronic C. pneumoniae infection may be a significant risk factor for the development of CAD, but this correlation should be investigated further.

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CAD= coronary artery disease

Objectives: To help clinicians and laboratory scientists recognize and utilize vasculitis-related ANCAs as an aid in diagnostic workup and patient follow-up, and be aware that ANCAs with different characteristics are commonly found in other chronic inflammatory conditions that persistently engage neutrophils in the inflammatory process.

Methods: Indirect immunofluorescence and enzyme immunoassay methods were used to detect ANCAs with both known and unknown neutrophil autoantigenic targets.

Results: Primary necrotizing small vessel vasculitides such as Wegener’s granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis, and renal-limited rapidly progressive necrotizing glomerulonephritis target either the serine protease proteinase 3 or myeloperoxidase  in azurophilic granules. In ulcerative colitis and rheumatoid arthritis, we found multiple ANCA targets contained in azurophilic and specific granules, the cytosol and the nucleus, whereas PR3² and MPO³ were not, or only weakly, recognized.

Conclusions: ANCAs typically found in active SVV⁴ are demonstrable both by indirect immunofluorescence and antigen-specific enzyme immunoassay, and strong reactivity to either PR3 or MPO is characteristic. Strong ANCA with MPO reactivity is also found in some patients with drug-induced syndromes (lupus, vasculitis). Intermediate to strong perinuclear ANCAs are found in a substantial proportion of patients with UC⁵ (40–60%) and RA⁶ (30–70%), but in these conditions the ANCAs have many antigen targets that are only weakly recognized.

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¹ ANCA = anti-neutrophil cytoplasm antibody

² PR3 = protease proteinase 3

³ MPO = myeloperoxidase

⁴ SVV = small vessel vasculitides

⁵ UC = ulcerative colitis

⁶ RA = rheumatoid arthritis