Hyposensitization. Comparing a purified (refined) allergen preparation and a crude aqueous extract from timothy pollen

Allergen injection immunotherapy for seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis is the most common of the allergic diseases. Despite improved understanding of the pathophysiology of allergic rhinitis and advances in its pharmacological treatment, its prevalence has increased worldwide. For patients whose symptoms remain uncontrolled despite medical treatment, allergen injection immunotherapy is advised. An allergen-based treatment may reduce symptoms, the need for medication and modify the natural course of this disease.

OBJECTIVES

To evaluate the efficacy and safety of subcutaneous specific allergen immunotherapy, compared with placebo, for reducing symptoms and medication requirements in seasonal allergic rhinitis patients.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2006), MEDLINE (1950 to 2006), EMBASE (1974 to 2006), Pre-MEDLINE, KOREAMED, INDMED, LILACS, PAKMEDINET, Scisearch, mRCT and the National Research Register. The date of the last search was February 2006.

SELECTION CRITERIA

All studies identified by the searches were assessed to identify randomised controlled trials involving participants with symptoms of seasonal allergic rhinitis and proven allergen sensitivity, treated with subcutaneous allergen specific immunotherapy or corresponding placebo.

DATA COLLECTION AND ANALYSIS

Two independent authors identified all studies reporting double-blind, placebo controlled randomised trials of specific immunotherapy in patients with seasonal allergic rhinitis due to tree, grass or weed pollens. Two authors independently performed quality assessment of studies. Data from identified studies were abstracted onto a standard extraction sheet and subsequently entered into RevMan 4.2.8. Analysis was performed using the Standardised Mean Difference (SMD) method and a random-effects model; P values < 0.05 were considered statistically significant. The primary outcome measures were symptom scores, medication use, quality of life and adverse events.

MAIN RESULTS

We retrieved 1111 publications of which 51 satisfied our inclusion criteria. In total there were 2871 participants (1645 active, 1226 placebo), each receiving on average 18 injections. Duration of immunotherapy varied from three days to three years. Symptom score data from 15 trials were suitable for meta-analysis and showed an overall reduction in the immunotherapy group (SMD -0.73 (95% CI -0.97 to -0.50, P < 0.00001)). Medication score data from 13 trials showed an overall reduction in the immunotherapy group (SMD of -0.57 (95% CI -0.82 to -0.33, p<0.00001)). Clinical interpretation of the effect size is difficult. Adrenaline was given in 0.13% (19 of 14085 injections) of those on active treatment and in 0.01% (1 of 8278 injections) of the placebo group for treatment of adverse events. There were no fatalities.

AUTHORS' CONCLUSIONS

This review has shown that specific allergen injection immunotherapy in suitably selected patients with seasonal allergic rhinitis results in a significant reduction in symptom scores and medication use. Injection immunotherapy has a known and relatively low risk of severe adverse events. We found no long-term consequences from adverse events.

Nasal congestion during the menstrual cycle

Oestrogens have been considered to cause nasal congestion during the menstrual cycle and during pregnancy. The aim of the present study was to evaluate the degree of nasal congestion during the menstrual cycle in healthy women. Nasal peak expiratory flow (nPEF) was measured and subjective nasal stuffiness was scored morning and evening by 27 women for 3 months and by 14 women for 6 months. During the menstrual days, when the serum oestrogen level is lowest, the morning nPEFs were significantly lower compared with the rest of the cycle (P = 0.0012). The difference was most pronounced for the second day of the cycle (P = 0.00034). The correlation between nPEFs and the subjective scores was high (R = 0.98), while the coefficient of variation within the series of three nPEF recordings was low (6.4%). It is concluded that the nasal obstruction experienced during menstruation cannot be explained by increased serum levels of oestrogen.

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. II. Comparison between parameters assessing the efficacy of immunotherapy

Specific immunotherapy is effective in alleviating symptoms in grass pollen-induced rhinitis, but there are no clear data demonstrating a correlation between symptom-medication scores and objective parameters. Twenty-five patients taking part in a double-blind, placebo-controlled immunotherapy with mixed grass pollen-formalinized allergoids were studied. All patients had the same investigations. Symptom-medication scores were significantly (p less than 0.005, Mann-Whitney U test) reduced in the treated group by comparison to the placebo-treated patients. Nasal challenges performed with threefold increasing numbers of orchard grass-pollen grains demonstrated that patients treated with allergoid tolerated a significantly (p less than 0.005, Wilcoxon W test) greater number of grains after treatment, whereas there was no mean difference in the placebo-treated patients. There was a significant (p less than 0.005, Spearman rank-correlation) correlation between nasal challenges and symptom scores during the season. The skin prick test end point was significantly (p less than 0.001, Wilcoxon W test) reduced after treatment in the allergoid-treated group and remained unchanged in the placebo-treated group. There was a significant (p less than 0.001) correlation between the skin prick test end point and symptom scores during the season. Serum grass-pollen IgG titrated by a solid-phase radioimmunoassay with Staphylococcus A protein was significantly (p less than 0.01, Wilcoxon W test) increased after treatment with allergoid, but there was no significant correlation between IgG titer and symptom scores during the season. Serum grass-pollen IgE increased (p less than 0.04, Wilcoxon W test) in the treated group but there was no correlation with symptom scores.

Immunotherapy with partially purified and standardized tree pollen extracts. II. Results of skin prick tests and nasal provocation tests from a three-year double-blind study of patients treated with pollen extracts either of birch or combinations of alder, birch and hazel

Patients allergic to tree pollen entered a 3-year course of immunotherapy (1980-83) with either birch pollen extracts alone (n = 26) or patient-tailored extracts of birch, alder and hazel pollen (n = 27). The clinical and immunological results of this study are published elsewhere. This paper contains an evaluation of skin prick test and nasal provocation test results. There were no significant differences between the two treatment groups concerning these two parameters. In both groups the allergen-specific sensitivity in the skin showed seasonal variations but a significant decrease. During the years of treatment there was also a significant decrease in the specific sensitivity of the nasal mucosa. With the present demands for purification and standardization of allergen extracts it is of practical and economic interest to know that tree pollen-allergic patients showing positive reactions to birch, alder and hazel extracts can be effectively treated using birch pollen extract alone.

Timothy-specific IgG antibody levels vary with the pollen seasons

Serum samples were collected from eight grass pollen hypersensitive children during a 4-year period. The sera were assayed for contents of timothy-specific IgE antibodies by RAST. Timothy-specific IgG and IgA antibodies were quantified by a refined ELISA in which covalent binding of the antigen to the polystyrene solid phase had been performed. IgG antibodies were also assayed by a Sepharose-protein-A technique with radiolabelled timothy allergens as the antigen. It was possible to register clearcut seasonal variations with postseasonally boosted antibody levels not only of timothy-specific IgE but also of IgG antibody. Both IgG1 and IgG4 antibodies specific for timothy showed seasonal variations of a similar degree. It was not possible to register seasonal variations of the same magnitude of timothy-specific IgA antibodies.

Methodological aspects of nasal allergen challenges based on a three-year tree pollen immunotherapy study

During 3 years of immunotherapy with tree pollen extracts, 31 patients were provoked annually. Changes in nasal reactivity were followed by registration of expiratory nasal peak flow, number of sneezes, and amount of secretion. The reproducibility of the peak flow measurements was studied. The results from all three parameters were used to form a total nasal provocation score which, better than each parameter separately, could demonstrate the variation in sensitivity. Provocation with an allergen concentration of 1 HEP was the most effective means of showing changes in specific sensitivity of nasal mucosa.

Oral administration of grass pollen to hay fever patients. An efficacy study in oral hyposensitization

Oral hyposensitization is still widely used in the treatment of allergic diseases, but controlled studies proving a beneficial effect are lacking. Fifty-eight hay fever patients were admitted to a double-blind placebo efficacy study in oral hyposensitization. An enterosoluble tablet containing timothy whole pollen or placebo was taken daily. Preseasonally, the actively treated patients received 4,315,000 PNU (880,260 AUR) and totally for 6 months 8,915,000 PNU (1,818,660 AUR). Such high doses have never been tried in similar studies. A new principle has been used - "the pollen count interval method" - in the evaluation of symptom and medication score. The study failed to prove any beneficial effect of oral hyposensitization measured by symptom score, medication score, nasal provocation test or skin prick test. There was no change in timothy specific IgE and IgG which could be caused by the treatment. The possibility that oral hyposensitization might be an effective treatment of hay fever in the future is discussed, but it is concluded that the present regimens cannot be recommended.

Comparison between rush immunotherapy with a standardized allergen and an alum adjuved pyridine extracted material in grass pollen allergy

Rush immunotherapy with a standardized and lyophilized cocksfoot pollen extract was performed in twenty-three allergic subjects and compared with classical immunotherapy done with an alum adjuved, pyridine extracted cocksfoot pollen extract (fifteen subjects) and a control group of ten patients. The three groups were perfectly matched. Clinical benefits were analysed by means of symptom scores. It was shown that rush immunotherapy gave significantly better results when asthma or rhinitis was considered than either classical immunotherapy (P less than 0.02) or in the control group (P less than 0.01 and 0.02). Skin tests were significantly reduced after rush immunotherapy and did not change in the two other groups. After the pollen season the skin test reactivity was increased in the rush immunotherapy group. Cocksfoot pollen specific IgE did not vary significantly in the three groups. Cocksfoot pollen specific IgG was significantly (P less than 0.05) increased in the rush immunotherapy group before the pollen season and did not vary significantly in the other groups.

Clinical trial of hyposensitisation in hay fever: two methods of relating symptom scores to daily pollen counts

Two methods of relating daily pollen counts to patients' symptom scores in clinical trials of hyposensitisation in hay fever are described. The problems involved in comparing results from different centres and years of a trial are discussed with particular reference to symptoms which are not pollen related. The Normalised Regression method is a powerful technique, but often the Pollen Interval method is preferable on the grounds of simplicity of communication and calculation.

Clinical effects of hyposensitization using a purified allergen preparation from Timothy pollen as compared to crude aqueous extracts from Timothy pollen and a four-grass pollen mixture respectively

Most extracts used in hyposensitization are complex and ill-defined mixtures of a large number of antigenic components. A highly refined (purified) and well-characterized allergen preparation from Timothy pollen (Phleum pratense) is now available. This paper describes the results of hyposensitization for 3 years comparing the purified preparation Timothy N, the crude extract Timothy O and a four-grass mix in sixty patients with allergic rhinitis due to grass pollen. The sixty patients were randomized into three groups and compared with a control group not hyposensitized. All three groups showed a significant decrease in clinical symptoms compared with the control group. The Timothy N group had a significantly higher nasal tolerance shown by nasal challenge test after 3 years' treatment than the group treated with the crude extract (P = 0.05). In addition, the Timothy-N-treated patients needed significantly less antihistaminic medication than the patients having received the crude extract or the four-grass mix (P = 0.02 and P = 0.01, respectively).

Side effects during immunotherapy with purified grass pollen extracts

In a 3-year prospective double blind study, grass pollen allergic patients were allocated to perennial hyposensitization with the timothy major allergens Nos. 19 and 25 (2-component extract) or a 20-component timothy extract. The extracts were biologically standardized and adsorbed to aluminium hydroxide for treatment. Systemic side effects (SSE) had début after 1 1/2-5 h and lasted without treatment 1/2-10 h. Treatment with the 2-component extract showed preponderance of minor SSE (arthralgia, rhinitis, tiredness, headache, conjunctivitis, nausea, flu-like symptoms), but major SSE (urticaria, angioedema, asthma) were equally distributed between treatment with the two timothy extracts. Major SSE complicated the treatment before the first grass pollen season in 33% of the patients vs. only in 3% during the subsequent perennial therapy, and developed (92%) at high single dose of greater than or equal to 1,000 biological units. The majority (69%) were later able to reach the same or higher dose without relapse. Most (62%) patients with major SSE were predicted by high nasal sensitivity before treatment. Only 18% of the patients had immediate local skin reactions of greater than or equal to 2 cm, but delayed local side effects of greater than or equal to 10 cm were recorded in 70%. Immediate skin reactions did not correlate with delayed skin reactions or with SSE, but delayed local side effects tended towards negative correlation with major SSE. A mean area reduction of 50% of the delayed skin reactions was recorded by repetition of a single dose. Subcutaneous nodules appeared at single doses of greater than or equal to 5,000 biological units. Only 5% of the patients contracted nodules during initial preseasonal therapy compared with 38% during subsequent perennial dosage. The nodules contained typical benign granulomas, and the frequency in the two groups was proportionate to the quantity of aluminium in the two extracts.

Immunotherapy with grass pollen major allergens

Perennial hyposensitization with a partially purified timothy extract resulted in a statistically significantly higher degree of clinical protection than treatment with the two timothy major allergens (Nos. 19 and 25) and protected better from the second--than during the first grass pollen season. The extracts were standardized biologically and adsorbed to aluminium hydroxide for administration. The therapy had a more beneficial influence on sneezing than on rhinorrhoea and blockage of nasal airways, and an excellent effect on grass pollen asthma was obtained with the partially purified timothy extract. Associated birch pollen allergy was not influenced by hyposensitization with grass pollen.

Nasal and skin sensitivity during immunotherapy with two major allergens 19, 25 and partially purified extract of timothy grass pollen

In a double blind 3-year prospective study 40 grass pollen allergic patients were allocated to specific immunotherapy (hyposensitization) with two timothy major allergens, 19, 25, or partially purified timothy extract. The extracts were biologically standardized and coupled to aluminium hydroxide for treatment. Efficacy of hyposensitization was evaluated by titrated nasal provocations and skin prick tests with the two treatment extracts and a five-gram mixture. The threshold dose for skin prick test (skin thresholds) produced reactions identical to histamine chloride 5.43 mmol/l and the threshold dose for nasal provocations (nasal thresholds) produced two of the three reactions: at least 0.5 ml of nasal secretion, at least five sneezes, and/or at least a 20% fall in nasal peak flow. Nasal thresholds showed highest efficacy from partially purified timothy extract but equal protection against timothy and the five-grass mixture. Nasal thresholds of 14 untreated patients corresponded to treatment with the two major allergens. Changes in skin and nasal thresholds after 12 and after 54 weeks of treatment predicted the severity of hay fever. Increase in nasal thresholds coincided with a marked effect on asthma. Nasal thresholds below 1 HEP before treatment predicted major systemic side effects.