Allergen of the Month—Stemphylium

Allergen of the MonthdStemphylium There are around 33 species of Stemphylium, many of which are saprophytic and have worldwide distribution. However, several species such as S solani are leaf-spotting parasites on plants like tomato, potato, onion, and cotton.1e4 Growth on hosts is facilitated by humidity of 85e90% and greater than 8 hours of wetness  at about 18 C. Stemphylium is the asexual anamorph stage of the ascomycete Pleospora. The sexual ascospores will develop in cold laboratory conditions, but it is unclear what factors are important in natural settings. Stemphylium spores are dry and easily become airborne, and may be more prevalent inland.2,5 Spores are found frequently on samplers, but usually in quantities about one quarter of those of Alternaria.6 Counts peak in the late spring to early summer.7,8 Stemphylium-induced rhinitis and asthma have been documented by nasal and bronchial provocative challenge in skin test or serologic positive children.9 Angioedema has been attributed to Stemphylium, as has allergic bronchopulmonary mycosis.10,11 Antibacterial and anticancer effects have been found in Stemphylium derivatives.12,13 A plant toxin, stemphol, is also produced.14 Pleospora/Stemphylium is closely related to Alternaria and recent taxonomy places it as a sister clade to the latter.15 Polyclonal antibodies to Alternaria alternata cross-react broadly to Stemphylium, Epicoccum, Drechslera, and Exserohilum, while not reacting with Penicillium, Aspergillus, Fusarium, and Cladosporium.16 The major Alternaria antigen, Alt a 1, appears to be very abundant in Stemphylium and is expressed in other Pleosporaceae members as well.17,18 Spores are formed from the tips of nodose or swollen pale green-brown conidiophores, either singularly or in small clumps. Spores are multicellular, with 6e16 cells, pale to dark brown, oblong, rounded on ends, 24e33 x 15e24 mm. There are usually 3 horizontal and 1e3 vertical septa, with a constriction at the midhorizontal septum. Surface is scabrate to verrucate. Spores are not found in chains or beaked like Alternaria.2,19 Text & Photography: Richard W. Weber, M.D. References [1] Shishkoff N, Lorbeer JW. Etiology of Stemphylium leaf blight of onion. Phytopathol. 1989;79:301e304. [2] Bassett IJ, Crompton CW, Parmalee JA. An atlas of airborne pollen grains and common fungus spores of Canada. Hull, Quebec: Printing and Publishing, Supply and Services Canada; 1978:297e299. [3] Inderbitzin P, Mehta Y, Berbee ML. Pleospora species with Stemphylium anamorphs: a four locus phylogeny resolves new lineages yet does not distinguish among species in the Pleospora herbarum clade. Mycologia. 2009;101:329e339. [4] Hong SK, Choi HW, Lee YK, Shim HS, Lee SY. Leaf spot and stem rot on Wilford swallowwort caused by Stemphylium lycopersici in Korea. Mycobiol. 2012;40:268e271. [5] Al-Doory Y, Domson JF. Mould Allergy. Philadelphia: Lea & Febiger; 1984: 255. [6] Elvira-Rendueles B, Moreno J, Garcia-Sanchez A, et al. Air-spore in Cartagena, Spain: Viable and non-viable sampling methods. Ann Agr Environ Med. 2013;20:664e671. [7] Oliviera M, Ribeiro H, Delgado L, et al. Outdoor allergenic fungal spores: Comparison between an urban and a rural area in northern Portugal. J Investig Allergol Clin Immunol. 2010;20:117e128.

[8] Hasnain SM, Akhter T, Wagar MA. Airborne and allergenic fungal spores of the Karachi environment and their correlation with meteorological factors. J Environ Monit. 2012;14:1006e1013. [9] Lelong M, Henard J, Wattre P, et al. Does immediate-type respiratory allergy occur regarding Stemphylium? Evaluation of 39 challenge tests. Allerg Immunol (Paris). 1986;18:21e26. [10] Gaudibert R. Quincke’s edema due to Alternaria and Stemphylium. Rev Fr Allergol. 1971;11:75e77. [11] Chowdhary A, Agarwal K, Kathuria S, et al. Allergic bronchopulmonary mycosis due to fungi other than Aspergillus: a global overview. Crit Rev Microbiol. 2014;40:30e48. [12] Zhou XM, Zheng CJ, Song XP, et al. Antibacterial a-pyrone derivatives from a mangrove-derived fungus Stemphylium sp. 33231 from the South China Sea. J Antibiot (Tokyo). 2014;67:401e403. [13] Teiten MH, Mack F, Debbab A, et al. Anticancer effect of altersolanol A, a metabolite produced by the endophytic fungus Stemphylium globuliferum, mediated by its pro-apoptotic and anti-invaasive potential via the inhibition of NF-kB activity. Bioorg Med Chem. 2013;21:3850e3858. [14] Solfrizzo M, Strange RN, Sabia C, Visconti A. Production of a toxin stemphol by Stemphylium species. Nat Toxins. 1994;2:14e18. [15] Woudenberg JHC, Groenwald JZ, Binder M, Crous PW. Alternaria redefined. Studies Mycol. 2013;75:171e212. [16] Schmechel D, Green BJ, Blachere FM, et al. Analytical bias of cross-reactive polyclonal antibodies for environmental immunoassays of Alternaria alternata. J Allergy Clin Immunol. 2008;121:763e768. [17] Agarwal MK, Jones RT, Yunginger JW. Shared allergenic and antigenic determinants in Alternaria and Stemphylium extracts. J Allergy Clin Immunol. 1982;70:437e444. [18] Sáenz-de-Santamaria M, Postigo I, Gutierrez-Rodríguez A, et al. The major allergen of Alternaria alternata (Alt a 1) is expressed in other members of the Pleosporaceae family. Mycoses. 2006;49:91e95. [19] Kapp RO. How to Know Pollen and Spores. Dubuque, IA: Wm. C. Brown Co; 1969:207.

Reprints: Richard W. Weber, M.D. National Jewish Health 1400 Jackson Street Room J326 Denver, CO 80206