Immune response profiles after caterpillar exposure: a case report.

Rationale: The role of the immune response to caterpillar exposure is not well described. This case study is the first to report a patient who presented with an allergic reaction after exposure to the larvae of the sycamore tussock moth, Halysidota harrisii Walsh, 1864.

Methods: Blood was collected from an allergic asthmatic adult (m/42 y/o) at 2 hrs - 2 wks after contact urticaria with associated dyspnea after exposure to the larvae of the sycamore tussock moth, Halysidota harrisii Walsh, 1864. Distributions of blood lymphocytes (CD4(+), CD8(+), CD8(+)CD60(+), CD19(+), CD23(+), CD16/56(+), CD25, CD45RA(+), CD45RO(+)), monocytes (CD1d(+)), levels of serum immunoglobulins (IgM, IgG, IgA, IgE), and cytokines (IFN-γ, IL-4, TNF-α) were studied (flow cytometry, nephelometry, UniCAP Total IgE Fluoroenzymeimmunoassay, cytokine ELISA, clinical toxicology).

Results: Numbers of CD4(+) T cells, CD25(+) cells, CD19(+) B cells, and CD1d(+) monocytes decreased (22, 27, 33, 20%, respectively) one week post reaction, CD45RA(+) naïve T cells decreased at 36 hours (21%),while CD8(+)CD60(+) T cells and CD23(+) cells decreased 48 hrs (33, 74%, respectively) post reaction. In contrast, numbers of CD16/56(+) NK precursor cells increased (60%) 12 hrs, then decreased (65%) 48 hrs post reaction; other lymphocyte subsets were unaffected. Serum IgM, IgG and IgA were within normal range; however, serum IgE demonstrated a bimodal elevation at 2 hrs (15%) and one week post reaction. Levels of IFN-γ, IL-4, and TNF-α were not detected in serum pre-exposure (<1.0-4.0 pg/mL). However, high levels of IFN-γ (187-319 pg/mL) and TNF-α (549-749 pg/mL) were detected in serum 24-36 hrs and 3.5-24 hrs post reaction, respectively. In contrast, levels of IL-4 were undetected (<1.0 pg/mL) in serum at all time points.

Conclusions: Exposure to the larvae of the sycamore tussock moth, Halysidota harrisii Walsh, 1864 may result in increased cytokine levels and blood CD16/56(+) NK precursor cells.