Host immune responses in dermatophytes infection

Abstract

Dermatophytosis is a skin infection caused by keratinophilic, filamentous fungi. These are highly prevalent, common mycoses, affecting approximately 20% of the population. These fungi invade the stratum corneum, and other keratinised tissues, like nails and hair, where they grow by secreting enzymes and degrading keratin to obtain nutrients. Clinical presentation is variable and may depend on many factors, such as the infection site, the host's immunity and the dermatophyte's virulence. Generally, patients with acute superficial dermatophytosis mount cell‐mediated immune responses. However, those suffering from chronic or recurrent infections are unable to develop this response, for reasons yet unknown. Several reports have described severe and occasionally life‐threatening invasive diseases (deep dermatophytosis) associated with genetic mutations in the innate immunity‐associated molecule CARD9, displaying the need to better understand its immune response. These dermatoses have substantial clinical consequences, producing chronic and difficult to treat skin lesions. They also lead to a decline in the patient's quality of life and impact their self‐esteem. This review summarises findings on the immune response against dermatophytes.

Nail Clipping with PAS Stain and Correlation with Fungi Isolated in Culture: A Valuable Exchange in the Diagnosis of Onychomycosis

“…However, dermatophyte fungi also displayed irregular shapes, albeit rarer than the long, thick smooth hyphae typically found. It is unclear why marked morphological changes occur in dermatophytes, but fungal viability is likely influenced by the interaction with the immune response of the host [12]. The presence of yeast-like structures proved statistically significant for differentiating between filamentous fungi and yeasts ( p = 0.0339).…”

Relapsed boyhood tibia polymicrobial osteomyelitis linked to dermatophytosis: a case report

“…This involves pattern-recognition receptors (PRR) and C-type lectin receptors (CLR) with Toll-like receptors (TLR). The PRRs are expressed on host macrophages, dendritic cells, keratinocytes and neutrophils, which release proinflammatory cytokines interleukin (IL) (IL-1β, IL-6 and IL-17), chemokines (IL-8, MCP-1, eotaxin and eotax- in-2) and immunomodulatory lymphokines (IL-4 and IL-13) [ 6 , 21 ]. These factors further stimulate T- and B-lymphocyte proliferation to produce immunoglobulins (Ig).…”

“…Dermatophytosis is a superficial fungal infection mostly restricted to keratinized tissues, which stimulates cell-mediated immune responses in the acute phase. However, these immune responses appear to be transient, as they are not present in patients who suffer from chronic or recurrent infections [ 6 , 7 ]. Osteomyelitis is rarely caused by fungal infection [ 8 , 9 ], and there are no documented cases of Staphylococcus aureus (S. aureus) and corynebacterium osteomyelitis whose recurrence was accompanied by dermatophytosis.…”

Detection of emerging genotypes in Trichophyton mentagrophytes species complex: A proposal for handling biodiversity in dermatophytes

“…Most pathogenic agents of humans originated from domesticated animals such as cattle, horse or camels ( Deng et al, 2008 ; Morrell and Stratman, 2011 ; Hameed et al, 2017 ). Infections by zoophilic dermatophytes cause highly inflammatory lesions due to immunopathogenesis ( Drouot et al, 2009 ; Celestrino et al, 2021 ; Sardana et al, 2021 ). The spectrum of infections of urban populations has changed in favor of species with human-to-human transmission and milder clinical pictures, in addition to those by pet-associated species causing self-limiting outbreaks.…”