[Local immunotherapy]

Specific immunotherapy, together with avoidance of the allergen and symptomatic treatment, forms part of the treatment of allergic pathology. The oldest, best known and most studied form is subcutaneous immunotherapy (SCIT), whose efficacy, both in the short and the long term, has been widely demonstrated in numerous studies. However, in spite of having been shown to be safe, it is not free of adverse effects and must be administered under the supervision of medical personnel. This has encouraged the search for new ways of administration of similar efficacy, with a good safety profile and good adherence on the patient's side. Sublingual immunotherapy (SLIT) is the most relevant of the different alternatives studied. In this alternative the antigen is administered in the form of drops under the tongue. There are different dosages of administration depending on the allergen involved. The optimum treatment dose has still to be determined, at present a wide range of dosages are found in comparison with subcutaneous immunotherapy. Its mechanism of action is little known although immunological changes have been observed in different studies. SLIT has shown a good safety profile with scarce secondary effects, normally of a local character. Similarly, different clinical tests have been carried out in which its efficacy has been shown in the treatment of respiratory allergy both in children and in adults. For this reason, although there are still unresolved data concerning this way of administering the immunotherapy, it has been proposed by the WHO as a valid alternative to SCIT.

[From rhinitis to asthma, one or two diseases?]

Rhinitis and asthma commonly coexist in allergic patients. This observation might be attributable to their coexistence in time, but it is also possible that both diseases are the opposite poles of a single disease affecting the respiratory system, or even an anomalous systemic immune response to the allergen. Nose-lung interactions have been widely studied from epidemiological, physiopathological, aetiological and pharmacological aspects. In the present article we review this topic and its main clinical implications.

[Food allergy in the XXI century]

Food allergy is a clinical state of high frequency and possible risk to life. This article reviews the foodstuffs most often responsible for serious reactions, including data from the Autonomous Community of Navarre. Given that dietetic elimination is the primordial long term treatment for food allergy, its difficulties, limitations and risks are analyzed. Finally, we set out the new perspectives offered by technology in the field of food allergy, both in the production of hypoallergens and in the development of new forms of immunotherapy.

[Anaphylaxis]

Anaphylaxis is a potentially mortal, underdiagnosed clinical picture. The most frequent triggering agents are drugs and foodstuffs. The first therapeutic option, adrenaline, although clearly indicated, is not carried out with the desired frequency due basically to the high number of cases of anaphylaxis that are not diagnosed as such. In patients with a first episode of anaphylaxis, posterior aetiological diagnosis is crucial to avoid the appearance of new episodes. The only case of anaphylaxis in which immunotherapy with the allergen must be evaluated, is that in which the causal agent is the poison of hymenopters.

[Latex allergy. Clinical manifestations in the general population and reactivity crossed with foodstuffs]

Because of widespread latex manufacturing in the last decades, latex allergy has become an important clinical problem, not only in high-risk groups (health-workers) but also among the general population. Latex is used to produce a large variety of natural rubber products (medical equipment, household gloves, condoms, balls and balloons, footwear, baby pacifiers...) employed in the ordinary life, with high risk for patients allergic to latex. Among general population, children affected by myelomeningocele or spina bifida, have a higher risk to develop latex allergy. Clinical manifestations range from local reactions(contact dermatitis, urticaria), rhino-conjunctivitis, asthma, pharyngeal edema to severe systemic reactions such anaphylactic shock. Furthermore, latex can crossreact with some plant foods, and patients suffering from latex allergy often associate food allergy.

[Immunotherapy with grouped doses]

Once the efficacy and safety of immunotherapy with allergen extracts has been shown, recently it has become evident the need for perfecting those aspects of the treatment that can be improved, such as its dosage form. The conventional dosage of subcutaneous immunotherapy in the phase of dose increase is slow in reaching an efficient level. For this reason other alternative dosages to the conventional one have been tried out, such as grouped dosages, which shorten this period of dose increase. On condition that the safety of the treatment is guaranteed, these doses offer the advantages of reducing the economic cost and the time involved, of reducing the discomfort of the treatment and of improving the patient's adherence to the treatment, and possibly of reaching clinical efficacy more rapidly. Nonetheless, it is not easy to determine the suitable dosage of administration (the shortest and with the least number of adverse reactions) and this article reviews the existing problems when it comes to designing these grouped doses. Finally, we present the results of a comparative study between the conventional dose and a grouped dose, with a double blind design, carried out by us, which shows that the grouped dose is quicker in achieving the desired clinical efficacy, shortens the times of reduction of cutaneous sensitivity to the allergen and of modification of the immunological parameters, all with a low frequency of adverse reactions that is similar to that registered with the conventional dosage.

[Allergy to Anisakis simplex]

Anisakis simplex is a parasite, belonging to the Anisakidae family. The life cycle of the parasite can include one or more intermediary hosts, their final hosts being marine mammals or large fish, in which the larvae develop until the adult stage is reached. Man is an accidental host who acquires the larvae by eating raw or undercooked fish. Since the mid-50s, when the first case studies were published in Holland and Japan, new cases have been emerging in different countries including Spain. Parasitization of man by the living larva is known as anisakiasis, principally giving rise to digestive symptomology, with other rare cases described of invasion of other organs such as the lung, the liver, the spleen, the pancreas, etc. Clinical pictures of allergy to IgE mediated anisakis simplex have also been described: reactions by thermostable antigens of the parasite that develop in spite of the fish being cooked or frozen, and an acute digestive parasitization with allergic symptoms called gastro-allergic anisakiasis. In the diagnosis of anisakiasis and/or allergy to Anisakis, the antecedent of the prior ingestion of fish as well as the clinical accompaniment can form basic data of considerable orientational value, and endoscopy can reveal the presence of the larvae and make possible their extraction. Besides, in cases of allergy the detection test for specific IgE facing Anisakis simplex, and cutaneous tests with fish should be carried out. The best treatment for avoiding this parasitization is prophylactic, avoiding the consumption of raw or undercooked fish, while a fish free diet is necessary in cases of true allergy to the thermostable proteins of the parasite.

[Epicutaneous test with inhalers in the study of atopic dermatitis]

In some 80% of patients with atopic dermatitis, the presence of specific IgE is found when facing food or environmental allergens. It has also been demonstrated in a sub-group of patients with atopic dermatitis that the dermatitis lesions are exacerbated following the ingestion or inhalation of allergens, and that they improve with reduction of exposure to allergens. Although the prick method and the determination of specific IgE in serum are highly sensitive techniques, epicutaneous tests, applying the allergen directly to the skin, might be the ideal diagnostic method since they reproduce the characteristic inflammatory response of the disease on the affected organ itself, the skin. However, there is great variability in the results obtained through epicutaneous tests with aeroallergens, basically due to methodological differences, which are reviewed in this paper. Finally, we present the results of carrying out epicutaneous tests with inhalant allergens on our patients with atopic dermatitis and controls, where some 27% of positive patches were obtained, basically with acari, and in those patients with more severe dermatitis, without there being complete concordance with the prick technique. For this reason, the epicutaneous test appears to be a method of allergological diagnosis that might be useful and complementary to the routine techniques of the prick method and the determination of specific IgE in serum, but it is in need of suitable standardization.

Hepatitis E virus: relevance in blood donors and other risk groups

BACKGROUND AND OBJECTIVES

Hepatitis E virus (HEV) infection usually causes an acute self-limited disease. HEV is associated with feces-contaminated drinking water, but other vectors, such as blood, are possible. The aim of this study was to investigate the prevalence of HEV in blood donors and in two groups at high risk of parenteral infections, namely, hemodialysis patients and children infected with hepatitis C virus (HCV) via blood transfusion.

MATERIALS AND METHODS

We investigated the prevalence of anti-HEV in 863 blood donors, 63 hemodialysis patients, and 42 children infected with HCV posttransfusion.

RESULTS

The prevalence rates were 2.8, 6. 3%, and 0 respectively.

CONCLUSIONS

(1) The incidence of HEV in Spain is similar to that in other western European countries, and (2) HEV is probably not transmitted parenterally to children.

Hepatitis E virus: relevance in blood donors and risk groups

BACKGROUND AND OBJECTIVES

Hepatitis E virus (HEV) infection usually causes acute self-limited disease. HEV is associated with faecal-contaminated drinking water, but other vectors, such as blood, are possible. The aim of this study was to investigate the prevalence of HEV in blood donors and in two groups at high risk for parenteral infections, namely, haemodialysis patients, and children infected with HCV via blood transfusion.

MATERIALS AND METHODS

We investigated the prevalence of anti-HEV in 863 blood donors, 63 haemodialysis patients, and 42 children infected post transfusion with HCV.

RESULTS

The prevalence rates were 2.8, 6.3%, and zero, respectively.

CONCLUSIONS

(1) The incidence of HEV in Spain is similar to that in other Western European countries, and (2) HEV is probably not transmitted parenterally to children.

Posttransfusion hepatitis after induction chemotherapy in acute nonlymphoblastic leukemia: implications for long-term management and outcome

BACKGROUND

The purpose of this study was to evaluate 1) the incidence of hepatitis and its influence on the clinical management of and outcome in acute nonlymphoblastic leukemia (ANLL) patients in first complete remission and 2) the impact of routine hepatitis C virus screening on the incidence of hepatitis in these patients.

STUDY DESIGN AND METHODS

Clinical and blood bank charts were reviewed for 65 consecutive ANLL patients between 1985 and 1993 who achieved complete remission after a course of daunomycin and cytarabine (cytarabine: 200 mg/m2/day x 7 days in continuous infusion; daunomycin: 60 mg/m2/day for the first 3 days of the 7, as a bolus).

RESULTS

Only 43 percent of patients who developed hepatitis completed the scheduled therapy. Hepatitis did not decrease the probability of relapse (66 +/- 9% vs. 66 +/- 11%), but patients with changes in planned treatment, due to hepatitis or other causes, tended to have a higher relapse rate than patients without changes in consolidation therapy (56.5% vs. 40.4%; p = 0.10). This did not result in a decrease in disease-free survival, however, because of the higher number of treatment-related deaths in the patients without hepatitis (who completed the therapy). Over the period from 1985 through 1989, the 6-month actuarial probability of developing hepatitis was 42 percent. However, since 1989, when hepatitis C screening of blood donors was implemented, the incidence was reduced to 12.5 percent (p < 0.05), in spite of greater transfusion support (172 +/- 46 vs. 89 +/- 53, p < 0.01). No new cases of hepatitis were observed after the introduction of second-generation hepatitis C virus assays.

CONCLUSION

Hepatitis precludes the use of consolidation therapy in about half of ANLL patients, resulting, in the experience described here, in a trend toward a higher rate of relapse. Hepatitis C virus screening of blood components reduces the incidence of hepatitis in ANLL patients.

Antibodies to hepatitis C virus in human immunoglobulins: clinical meaning and diagnostic difficulties in children undergoing bone marrow transplant

Anti-HCV antibodies were detected in 11 children undergoing BMT. All of them had received intravenous immunoglobulins (Ig) at a dose of 500 mg/kg every 2 weeks for the first 100 days post-BMT. Antibody titers appeared after the first dose and became undetectable between 1 and 6 months after the last dose of Ig. Detection of anti-HCV antibodies in these multitransfused patients raised doubts about their clinical significance. The clearance of antibody titers in the ensuing months, negativity of HCV RNA in the serum of the patients and the presence of anti-HCV in some batches of the commercial preparations administered supported the diagnosis of a passive transfer of antibodies and that true HCV infection could be ruled out. Routine screening of donors with the most sensitive tests and exclusion of anti-HCV positive sera from plasma pools should be mandatory. The presence of anti-HCV in these products has important clinical implications, leading to more expensive and time-consuming diagnostic procedures.