Cryptococcus: History, Epidemiology and Immune Evasion

Abstract

Cryptococcosis is a disease caused by the pathogenic fungi Cryptococcus neoformans and Cryptococcus gattii, both environmental fungi that cause severe pneumonia and may even lead to cryptococcal meningoencephalitis. Although C. neoformans affects more fragile individuals, such as immunocompromised hosts through opportunistic infections, C. gattii causes a serious indiscriminate primary infection in immunocompetent individuals. Typically seen in tropical and subtropical environments, C. gattii has increased its endemic area over recent years, largely due to climatic factors that favor contagion in warmer climates. It is important to point out that not only C. gattii, but the Cryptococcus species complex produces a polysaccharidic capsule with immunomodulatory properties, enabling the pathogenic species of Cryptococccus to subvert the host immune response during the establishment of cryptococcosis, facilitating its dissemination in the infected organism. C. gattii causes a more severe and difficult-to-treat infection, with few antifungals eliciting an effective response during chronic treatment. Much of the immunopathology of this cryptococcosis is still poorly understood, with most studies focusing on cryptococcosis caused by the species C. neoformans. C. gattii became more important in the epidemiological scenario with the outbreaks in the Pacific Northwest of the United States, which resulted in phylogenetic studies of the virulent variant responsible for the severe infection in the region. Since then, the study of cryptococcosis caused by C. gattii has helped researchers understand the immunopathological aspects of different variants of this pathogen.

Cryptococcal chest wall mass and rib osteomyelitis associated with the use of fingolimod: A case report and literature review

“…This is mainly because of a robust Th1 immune response that is capable of controlling C. neoformans infection ( 2 ). In contrast, in immunocompromised patients, C. neoformans can cause severe disease with high mortality ( 3 , 4 ). C. neoformans has capsular polysaccharides located externally to the cell wall with the flexibility to alter the composition, thereby altering antigenic properties and evading the immune response ( 5 ).…”

Incidência de criptococose em pombos (Columba livia) e seu impacto na saúde pública em Porto Velho/RO

“…Cryptococcus neoformans, está relacionado as excretas secas, meio de cultura favorável para o seu desenvolvimento. Esse agente etiológico foi isolado e descrito pela primeira vez em 1894, pelo cirurgião Abraham Buschke e pelo patologista Otto Busse (Diniz-Lima et al, 2022). As Cryptococcus gattii são encontrados com maior frequência em climas tropicais e subtropicais, porém estudos indicam que está se alastrando pelas áreas geográficas, sendo capaz de se desenvolver em regiões temperadas (Cogliati, 2013;do Carmo et al, 2022;Firacative et al, 2018).…”

Pulmonary Fibrosis and Hypereosinophilia in TLR9-/- Mice Infected by Cryptococcus gattii

“…Cryptococcus gattii is a pathogenic encapsulated basidiomycete widely distributed in the environment and capable of infecting immunocompetent individuals, mainly affecting the lungs and central nervous system (CNS) [1][2][3]. C. gattii is saprophytic and can adapt to the most diverse environments and was the main etiological agent in the North Pacific outbreak that occurred in 1990s [4][5][6].…”

“…Glucuronoxylomannan (GXM) and glucuronoxylomannogalactan (GXMGal) polysaccharides are the main components of the capsule that covers the yeast and represent two of the most important virulence factors, although other virulence factors such as melanin production, abnormally sized yeast (titan cells), vesicle release and growth at 37 • C are also important and well-described in the literature [7][8][9][10][11][12][13]. The transmission can occur through the inhalation of basidiospores or yeast cells that are easily deposited in the alveoli, initially damaging the respiratory system and being able to spread to other organs, such as the brain [1][2][3].…”