OBJECTIVE: The aim of this study was to clone and express Hev b 3 and to obtain the immunologic active and soluble recombinant allergen for diagnosis of SB-associated latex allergy.
METHODS: A complementary DNA (cDNA) coding for Hev b 3 was amplified from RNA of fresh latex collected from Malaysian rubber trees (Hevea brasiliensis). PCR primers were designed according to sequences of internal peptide fragments of natural (n) Hev b 3. The 5'-end sequence was obtained by specific amplification of cDNA ends. The recombinant (r) Hev b 3 was produced in Escherichia coli as a 6xHis tagged protein. Immunoblotting and inhibition assays were performed to characterize the recombinant allergen.
RESULTS: An Hev b 3 cDNA clone of 922 bp encoding a protein of 204 amino acid residues corresponding to a molecular weight of 22.3 kd was obtained. In immunoblots 29/35, latex-allergic patients with SB revealed IgE binding to rHev b 3, as did 4 of 15 of the latex-sensitized group. The presence of all IgE epitopes on rHev b 3 was shown by its ability to abolish all IgE binding to nHev b 3. Hev b 3 is related to Hev b 1 by a sequence identity of 47%. Cross-reactivity between these 2 latex allergens was illustrated by the large extent of inhibition of IgE binding to nHev b 1 by rHev b 3.
CONCLUSION: rHev b 3 constitutes a suitable in vitro reagent for the diagnosis of latex allergy in patients with SB. The determination of the full sequence of Hev b 3 and the production of the recombinant allergen will allow the epitope mapping and improve diagnostic reagents for latex allergy.
METHODS: Fifty-four patients with pemphigus in this report were treated between 1981 and 1996, and were studied for several clinical features, treatment, course and prognosis.
RESULTS: Around 80% of pemphigus patients were Arabs, and Kuwaitis constituted the largest number (46.3%) with a female predominance (F: M = 2:1). Pemphigus vulgaris (PV) was the commonest clinical type. The mean age of onset was 36 years. The follow-up period ranged from 2 months to 12 years (mean, 4.5 years). The majority of the patients could be managed with low-dose steroids (30-60 mg/day). Twenty per cent of the patients were in complete clinical remission and were off systemic therapy for an average of 3 years. No death secondary to the disease or its treatment was observed.
CONCLUSIONS: Kuwaiti patients with pemphigus were observed to have a relatively young age of onset and a female predominance. Low doses of steroids were enough to control the disease in the majority, and at least 20% of patients were off therapy and in complete remission on follow-up.