Green Brett James, Yli-Panula Eija, Tovey Euan Roger
Department of Medicine, The University of Sydney, Sydney, NSW, Australia.
Allergol Int. 2006 Jun;55(2):131-9. doi: 10.2332/allergolint.55.131.
Accurate diagnosis of allergy to specific fungal species is confounded by the variability in allergens occurring with different diagnostic systems. We compared the halogen immunoassay (HIA), which uses allergens expressed by freshly germinated spores that are bound to protein binding membranes (PBM), with the commercial Pharmacia UniCap assay (CAP) and with skin prick tests (SPT).
Serum from 60 subjects was used; 30 were SPT positive and sensitized to at least one of Alternaria alternata or Aspergillus fumigatus and the other 30 were SPT negative to these fungi but known to be sensitized to non-fungal allergens. All sera were analyzed by CAP against A. alternata, A. fumigatus, Cladosporium herbarum and Epicoccum purpurascens. For HIA, spores from reference cultures belonging to these four species were germinated on PBM, laminated and then probed with each serum. Two independent observers using an ordinal ranking system quantified the intensity and occurrence of the resultant immunoglobulin E (IgE) immunostained haloes around spores and this was statistically compared with the results of the two conventional immunodiagnostic techniques.
Germinated conidia of each species expressed detectable allergen in the HIA. The agreement between the ordinal rank scores assigned by the pair of observers was very good (k >or= 0.8) and only differed for A. fumigatus (k = 0.66) . Between 3% and 7% of SPT negative sera was identified by HIA to have specific IgE towards A. fumigatus and A. alternata. For all four species tested there were strong correlations between HIA and CAP (P < 0.0001). However the correlation of both HIA and CAP to SPT was weaker for A. alternata (r(s) = 0.44, P < 0.0153) and absent for A. fumigatus.
Overall, the HIA is a new immunodiagnostic technique for the detection of sensitization to fungal allergens that correlates significantly with CAP and to a lesser extent with SPT. This may be due to extract variability and system differences. The significance of this derives from the unique ability of the HIA to measure IgE antibodies to the undegraded allergens that are actively secreted by germinating conidia and hyphae. These are the natural agents of exposure to fungi, and as such, are most likely to be relevant to clinical disease.
不同诊断系统中过敏原的变异性使得对特定真菌物种过敏的准确诊断变得复杂。我们将使用结合在蛋白质结合膜（PBM）上的新鲜萌发孢子所表达的过敏原的卤素免疫测定法（HIA）与商业Pharmacia UniCap测定法（CAP）以及皮肤点刺试验（SPT）进行了比较。
使用了60名受试者的血清；30名受试者SPT呈阳性，对链格孢或烟曲霉中的至少一种致敏，另外30名受试者对这些真菌的SPT呈阴性，但已知对非真菌过敏原致敏。所有血清均通过CAP针对链格孢、烟曲霉、草本枝孢和紫青霉进行分析。对于HIA，将属于这四个物种的参考培养物的孢子在PBM上萌发、层压，然后用每种血清进行检测。两名独立观察者使用序数排名系统对孢子周围产生的免疫球蛋白E（IgE）免疫染色晕圈的强度和出现情况进行量化，并将其与两种传统免疫诊断技术的结果进行统计学比较。
每个物种的萌发分生孢子在HIA中均表达出可检测到的过敏原。两名观察者分配的序数排名分数之间的一致性非常好（k≥0.8），仅烟曲霉的一致性有所不同（k = 0.66）。HIA鉴定出3%至7%的SPT阴性血清对烟曲霉和链格孢具有特异性IgE。对于所有测试的四个物种，HIA与CAP之间均存在强相关性（P < 0.0001）。然而，对于链格孢，HIA和CAP与SPT的相关性较弱（r(s) = 0.44，P < 0.0153），而对于烟曲霉则不存在相关性。
总体而言，HIA是一种用于检测对真菌过敏原致敏的新免疫诊断技术，与CAP有显著相关性，与SPT的相关性较小。这可能是由于提取物的变异性和系统差异所致。其意义在于HIA具有独特的能力，能够测量针对萌发分生孢子和菌丝体主动分泌的未降解过敏原的IgE抗体。这些是接触真菌的天然介质，因此最有可能与临床疾病相关。
