Treating Infectious Keratitis

Interactions of thymic stromal lymphopoietin with interleukin-4 in adaptive immunity during Aspergillus fumigatus keratitis

AIM

To investigate the potential interactions of thymic stromal lymphopoietin (TSLP) with interleukin-4 (IL-4) in adaptive immunity during fungal keratitis (FK).

METHODS

An FK mouse model was induced with Aspergillus fumigatus (AF) hyphal infection. Mice were divided into several groups: untreated, phosphate buffer saline (PBS), infected with AF, and pretreated with a scrambled siRNA, a TSLP-specific siRNA (TSLP siRNA), murine recombinant TSLP (rTSLP), immunoglobulin G (IgG), murine recombinant IFN (rIFN-γ), murine recombinant IL-4 (rIL-4), rIL-13, murine recombinant IL-17A (rIL-17A), and murine recombinant IL-17F (rIL-17F) groups. Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) or Western blot were performed to determine mRNA and protein levels in the inflamed cornea. Cytokine locations were observed by immunofluoresence staining after AF hyphal infection.

RESULTS

Compared to those in the untreated group, TSLP and T helper type 1 (Th1) cytokine levels in the AF group were upregulated at 24h post infection (hpi), and those of T helper type 2 (Th2) and T helper type 17 (Th17) cytokines were increased at 5d post infection (dpi). Th2 cytokine levels were decreased in the TSLP siRNA-pretreated group and increased in the rTSLP-pretreated group compared with the AF group. The TSLP level was increased in the rIL-4-pretreated group, but there were no significant changes among the other groups. Immunofluorescence staining showed cytokine locations after AF hyphal infection.

CONCLUSION

TSLP induces a Th2 immune response and promots Th2 T cell differentiation in vivo. IL-4 promotes TSLP secretion. Therefore, TSLP with IL-4 regulates adaptive immunity in FK.

Navigating a Curious Case of Unilateral Keratouveitis in Pakistan

Keratouveitis is a rare but potentially dangerous condition of the eye that requires prompt management otherwise it may result in severe visual impairment. We report a challenging case of unilateral keratouveitis.

A 40-year-old man presented with right eye erythema, epiphora, decreased vision, and severe pain from one month after failure to antibiotics treatment. Slit-lamp examination showed circumcorneal injection of conjunctiva, a central corneal ulcer, hypopyon and cells in the anterior chamber (AC). The culture and sensitivity of ocular tissue showed no growth of organisms. Intravitreal antibiotics (vancomycin and ceftazidime) along with anterior chamber tap led to resolution of the inflammation. The corneal ulcer was markedly reduced and vision was improved.

This case emphasizes two important points. First, how to approach a case of keratouveitis of uncertain etiology, in a less resourceful situation. Second, how to treat unilateral keratouveitis with intravitreal antibiotics and anterior chamber/vitreous tap.