The Phytopathogenic Fungus Pallidocercospora crystallina-Caused Localized Subcutaneous Phaeohyphomycosis in a Patient with a Homozygous Missense CARD9 Mutation
In the past decade, an increasing number of otherwise healthy individuals suffered from invasive fungal infections due to inherited CARD9 mutations. Herein, we present a patient with a homozygous CARD9 mutation who was suffering from localized subcutaneous phaeohyphomycosis caused by the phytopathogenic fungus Pallidocercospora crystallina which has not been reported to cause infections in humans.
The medical history of our patient was collected. P. crystallina was isolated from the biopsied tissue. To characterize this novel pathogen, the morphology was analyzed, whole-genome sequencing was performed, and the in vivo immune response was explored in mice. Whole-exome sequencing was carried out with samples from the patient’s family. Finally, the expression and function of mutated CARD9 were investigated.
A dark red plaque was on the patient’s left cheek for 16 years and was diagnosed as phaeohyphomycosis due to a P. crystallina infection. Whole-genome sequencing suggested that that this strain had a lower pathogenicity. The in vivo immune response in immunocompetent or immunocompromised mice indicated that P. crystallina could be eradicated within a few weeks. Whole-exome sequencing revealed ahomozygous missense mutation in CARD9 (c.1118G>C p.R373P). The mRNA and protein expression levels were similar among cells carrying homozygous (C/C), heterozygous (G/C), and wild-type (G/G) CARD9 alleles. Compared to PBMCs or neutrophils with heterozygous or wild-type CARD9 alleles, however, PBMCs or neutrophils with homozygous CARD9 alleles showed impaired anti-P. crystallina effects.
Localized subcutaneous phaeohyphomycosis caused by P. crystallina was reported in a patient with a homozygous CARD9 mutation. Physicians should be aware of the possibility of a CARD9 mutation in seemingly healthy patients with unexplainable phaeohyphomycosis.
KeywordsPhaeohyphomycosis Pallidocercospora crystallina CARD9 Homozygous missense mutations Primary immunodeficiency Inborn errors of immunity
We thank the patient and her family, for participating in this study. We thank for the Chigene (Beijing) Translational Medical Research Center Co. Ltd. for the technical support of the whole-exome sequencing analysis.
Y.G., Z.Z, J.G., C.Z., X.Z., E.D., W.L., and H.Q. conducted the research, analyzed, and interpreted data. G.W., C.M., and M.F. designed the research studies. Y.G., Z.Z., and J.G. drafted the manuscript and E.D., W.L., H.Q., G.W., C.M., and M.F. critically revised the manuscript.
This work was supported by the National Natural Science Foundation of China (Grant numbers 81371735 and 81672691) and the National Natural Science Foundation of Shaanxi Province (Grant number 21044091).
Compliance with Ethical Standards
This work was performed according to rules and regulations concerning the use of human materials from the patient, her parents, her son, and three healthy unrelated volunteers with written informed consent. The study was approved by the Clinical Research Ethics Committee of the Xijing Hospital in accordance with the institution’s guidelines. All experiments were carried out with adherence to the Declaration of Helsinki.
Conflict of Interest
The authors declare that they have no conflicts of interest.
- 1.Chowdhary A, Perfect J, de Hoog GS. Black molds and melanized yeasts pathogenic to humans. Csh Perspect Med. 2015;5(8):a19570.Google Scholar
- 4.Revankar SG, Baddley JW, Chen SCA, Kauffman CA, Slavin M, Vazquez JA, et al. A Mycoses Study Group international prospective study of phaeohyphomycosis: an analysis of 99 proven/probable cases. Open Forum Infect Di. 2017;4(4).Google Scholar
- 9.Tang J, Lin G, Langdon WY, Tao L, Zhang J. Regulation of C-type lectin receptor-mediated antifungal immunity. Front Immunol. 2018;9.Google Scholar
- 12.Glocker E, Hennigs A, Nabavi M, Schäffer AA, Woellner C, Salzer U, et al. A Homozygous CARD9 mutation in a family with susceptibility to fungal infections. N Engl J Med. 2009;21(4):372.Google Scholar
- 16.Rieber N, Gazendam RP, Freeman AF, Hsu AP, Collar AL, Sugui JA, et al. Extrapulmonary Aspergillus infection in patients with CARD9 deficiency. JCI Insight. 2016;1(17).Google Scholar
- 31.Johnson CJ, Davis JM, Huttenlocher A, Kernien JF, Nett JE. Emerging fungal pathogen Candida auris evades neutrophil attack. Mbio. 2018;9(4).Google Scholar
- 33.Drummond RA, Franco LM, Lionakis MS. Human CARD9: a critical molecule of fungal immune surveillance. Front Immunol. 2018;9.Google Scholar
- 37.Rosentul DC, Delsing CE, Jaeger M, Plantinga TS, Oosting M, Costantini I, et al. Gene polymorphisms in pattern recognition receptors and susceptibility to idiopathic recurrent vulvovaginal candidiasis. Front Microbiol. 2014;5.Google Scholar
- 41.Yang H, Cai Q, Gao Z, Lv G, Shen Y, Liu W, et al. Subcutaneous phaeohyphomycosis caused by Exophiala oligosperma in an immunocompetent host: case report and literature review. Mycopathologia. 2018.Google Scholar
- 42.Mijiti J, Pan B, de Hoog S, Horie Y, Matsuzawa T, Yilifan Y, et al. Severe chromoblastomycosis-like cutaneous infection caused by Chrysosporium keratinophilum. Front Microbiol. 2017;8.Google Scholar