Ocular lesions appearing in patients with sick building syndrome (SBS) are potentially a form of allergic disorder, with interleukin 4 (IL-4) playing a possible role, according to study results published in Journal of Asthma and Allergy.
SBS is a set of nonspecific symptoms associated with poor quality indoor environments. Symptoms can affect the eyes, nose, throat, and skin, along with headache and fatigue. Researchers previously investigated clinical and allergological aspects of SBS, specifically the allergic conjunctival diseases (ACD): allergic conjunctivitis (AC), atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC). In the current study, researchers investigated cytokine production profiles of conjunctival and peripheral blood lymphocytes in patients with SBS with ocular manifestations.
The researchers acquired conjunctival samples and peripheral blood mononuclear cells (PBMC) from 15 patients with SBS and ocular findings, along with 14 patients with AC, 14 patients with AKC, 21 patients with VKC, and 13 patients in a control group. The frequencies of cytokine producing T cells were then assessed for all patients
Comparisons of the PBMC samples from patients with SBS or ACD and controls found no significant differences in the percentage of interferon (IFN)-γ-producing CD4+ T cells, except between patients with AC and AKC (P <.05) and AC and VKC (P <.05). There were no significant differences in the percentage of IL-4 producing CD4+ T cells between patients with SBS and patients with ACD. However, the percentages of IL-4 producing CD4+ T cells were higher in patients with SBS (P <.01), AKC (P <.01), or VKC (P <.01) compared with controls.
In the conjunctival samples, the percentage of IFN-4 producing CD4+ T cells were significantly higher for patients with AKC (P <.001) and VKC (P <.01) compared with patients with SBS. The same was true for comparisons with AC (AKC P <.01; VKC P <.05) and controls (AKC P <.001; VKC P <.01). The percentage of IL-4-producing cells in patients with SBS was significantly higher compared with controls (P <.001) and lower compared with patients with AKC (P <.01) and VKC (P <.0001). For patients with AC, the percentage of IL-4-producing cells was higher than in controls (P <.01) and lower than in patients with AKC (P <.001) and VKC (P <.0001). There were no differences in the percentage of IL-4-producing cells between patients with SBS and AC, or between patients with AKC and VKC. Researchers also observed a significant correlation between clinical score and the percentage of IL-4-producing cells in the conjunctival samples.
The study was limited in the types of biomarkers assessed and in its lack of evaluation of potential targets such as chemokines, eosinophil cationic protein, matrix metalloproteinases, and periostin. Also, the study population was small and environmental parameters such as volatile organic compounds, odors, dust or bioaerosols were not investigated.
According to researchers, the “results indicate that the systemic cytokine production profile observed in CD4+ T cells of patients with SBS had different characteristics to that of normal controls, and suggest that increased frequency of IL-4 producing CD4+ T cells may be one reason for increased type 2 cytokine production in patients with SBS.”
Izake R, Kobayashi A, Fujita H, et al. Analysis of cytokine production profiles of local and systemic lymphocytes in sick building syndrome compared with ocular allergy. J Asthma Allergy. 2022:1115-1124. doi: https://doi.org/10.2147/JAA.S375080