IL-33-mediated innate response and adaptive immune cells contribute to maximum responses of protease allergen-induced allergic airway inflammation.

How the innate and adaptive immune systems cooperate in the natural history of allergic diseases has been largely unknown. Plant-derived allergen, papain, and mite allergens, Der f 1 and Der p 1, belong to the same family of cysteine proteases. We examined the role of protease allergens in the induction of Ab production and airway inflammation after repeated intranasal administration without adjuvants and that in basophil/mast cell stimulation in vitro. Papain induced papain-specific IgE/IgG1 and lung eosinophilia. Der f 1 induced Der f 1-specific IgG1 and eosinophilia. Although papain-, Der f 1-, and Der p 1-stimulated basophils expressed allergy-inducing cytokines, including IL-4 in vitro, basophil-depleting Ab and mast cell deficiency did not suppress the papain-induced in vivo responses. Protease inhibitor-treated allergens and a catalytic site mutant did not induce the responses. These results indicate that protease activity is essential to Ab production and eosinophilia in vivo and basophil activation in vitro. IL-33-deficient mice lacked eosinophilia and had reduced papain-specific IgE/IgG1. Coadministration of OVA with papain induced OVA-specific IgE/IgG1, which was reduced in IL-33-deficient mice. We demonstrated IL-33 release, subsequent IL-33-dependent IL-5/IL-13 release, and activation of T1/ST2-expressing lineage(-)CD25(+)CD44(+) innate lymphoid cells in the lung after papain inhalation, suggesting the contribution of the IL-33-type 2 innate lymphoid cell-IL-5/IL-13 axis to the papain-induced airway eosinophilia. Rag2-deficient mice, which lack adaptive immune cells, showed significant, but less severe, eosinophilia. Collectively, these results suggest cooperation of adaptive immune cells and IL-33-responsive innate cells in protease-dependent allergic airway inflammation.

Modulation of allergenicity of major house dust mite allergens Der f 1 and Der p 1 by interaction with an endogenous ligand.

Although many allergens bind endogenous molecules other than Abs in the human body, whether the interaction can modulate allergenicity has been unknown. Here, we investigated the effect of the interaction of recombinant major mite group 1 allergens (Der f 1 and Der p 1), which belong to the papain-like cysteine protease family, with an endogenous protease inhibitor, cystatin A, on their allergenicity. Cystatin A bound reduced forms of the allergens, in which the cysteine residue at the catalytic center of the protease activity was reduced by treatment with L-cysteine, but did not bind oxidized forms. Cystatin A partially inhibited the binding of IgE in mite-allergic volunteers' sera to the reduced forms, but unexpectedly enhanced the basophil histamine-releasing activity. A catalytic site-mutant of Der f 1 behaved in terms of histamine release, similarly to the reduced form. Molecular modeling showed that cystatin A interacts with the allergens within a narrow area. The results indicate that interaction with cystatin A reduces the limited number of IgE epitopes of the allergens but enhances their biological activity to release histamine, suggesting a new concept, that interaction between allergens and their endogenous ligands modulates the allergenicity even toward enhancement in the effector phase. On the other hand, i.p. immunization without alum of mice with cystatin A-treated reduced Der f 1 induced less serum Der f 1-specific IgE than immunization with reduced Der f 1 alone, suggesting that endogenous protease inhibitors suppress the induction of allergen-specific IgE, which is dependent on the enzymatic activity of cysteine protease-allergens, in the sensitization process.

[A case of hyperammonemia with encephalopathy related to FOLFIRI chemotherapy for advanced colon cancer].

A 50-year-old man undergoing operations for sigmoid colon cancer, small intestine invasion, and liver metastasis was given adjuvant chemotherapy postoperatively. During the course, lung, brain and bone metastasis were found, FOLFIRI therapy was started. Fifth FOLFIRI therapy was performed, but on the night of the next day, he was transported on an emergency basis to our hospital because of a coma. Laboratory examination revealed hyperammonemia, so aminoleban was started for its treatment. After 3 days in the hospital, consciousness and serum ammonia were improved. Cases of hyperammonemia caused by 5-FU have been reported in the literature, and this case was diagnosed with the same. Hyperammonemia should be taken into account as a differential diagnosis in the disturbance of consciousness in chemotherapy.

[A case of Wegener's granulomatosis with pachymeningitis].

A 49-year-old man was admitted to our hospital because of headache, rhinorrhea, and general fatigue. Chest CT revealed some lung nodules bilaterally, and laboratory data were positive for C-ANCA. Brain MRI revealed the findings of pachymeningitis. Wegener's granulomatosis (WG) was diagnosed by the pathological findings of his paranasal sinuses and kidneys. Most of his symptoms remarkably improved with oral corticosteroids and cyclophosphamide. A MEDLINE search about WG with pachymeningitis obtained only 15 cases previously reported in Japan. Considering those reports about WG with pachymeningitis in both Japan and overseas, in some cases pachymeningitis preceded WG, and relatively more cases than normal WG were negative for C-ANCA, furthermore the pathological findings of pachymeningitis were mainly necrotizing granuloma. Therefore pachymeningitis with WG might be mainly composed of granuloma rather than angitis and which might be a expansion of granulomatous inflammation of upper respiratory tract.