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.