OBJECTIVES: We studied the role of the regulatory T cells CD4+CD25+ (Treg) and activated CD4+CD30+ cells in the pathogenesis of asthma and their association with apoptosis and NF-kappaB in patients with mild intermittent asthma (MA), severe persistent asthma (SA), and healthy volunteers (HV).
METHODS: Peripheral blood lymphocytes (PBL) were extracted from asthmatic patients during exacerbations, and CD4+ cells were separated using Dynal beads. Immunostaining of whole PBL for NF-kappaB, Bax, and Bcl-2, and immunostaining of CD4+ cells for CD25+ and CD30+ cells were performed using immunocytochemistry.
RESULTS: Treg cells were expressed at higher levels in MA than in HV and SA (P < .05), while CD30+ T cells were expressed at higher levels in both SA and MA than in HV (P < .05), although there was no remarkable difference between SA and MA (P>.05). Levels of NF-kappaB, Bcl-2, and Bcl-2/Bax increased, whereas those of Bax decreased, progressively, from MA to SA (P < .05). NF-kappaB levels correlated directly with the Bcl-2/Bax ratio and with CD4+CD30+ cells in SA and MA, whereas CD4+CD30+ cells correlated inversely with the Bcl-2/Bax ratio.
CONCLUSIONS: Unregulated Treg cells probably return inflammatory responses to normal values during exacerbations in MA; however, expression of Treg cells was extensively diminished in SA, leading to probable loss of suppressive control over underlying immune reactions. CD4+CD30+ cells were associated with the pathogenesis of asthma but not with severity. NF-kappaB seems to be the central inflammatory factor in SA, with a remarkable loss of PBL apoptosis, diminished Treg levels, and high CD30+ cell levels that probably induce NF-kappaB, which in turn blocks the proapoptotic potential of CD30 induction itself.
Six Hevea brasiliensis latex protein allergens, Hevb 1, Hev b 2, Hev b 3, Hev b 4, and two variants of Hev b 7 (7b and 7c), were purified from Hevea latex, while a seventh protein, Hev b 5, was prepared in recombinant form. The presence of these proteins in glove extracts was indicated by their respective antibodies in the serum of rabbits immunized against the extracts. The relative propensities of IgE binding to the individual latex allergens were compared using sera from latex-allergic patients. IgE recognition of Hev b 4, Hev b 7b, Hev b 5 and Hev b 2 was most frequently encountered, with 75, 61, 31 and 28%, respectively, of the patient sera reacting. Sensitivity to multiple latex proteins was common, and out of the 31 seropositive patients, 23 (74%/ ) had IgE against at least two latex allergens, while 12 (39%) had IgE specific for at least three allergens. Statistical analysis of the data suggested that many patients might have acquired sensitivity to Hev b 2, Hev b 4 and Hev b 7b from a common source. (e.g., from latex products). On the other hand, sensitivity to Hev b 5 and to Hev b 7c were interrelated. It is plausible that sensitivity to these two proteins might have been acquired from sources other than latex products (e.g., from certain foods).