Association between anti-Anisakis simplex antibodies and interleukin-7 levels

IL-7 is a crucial factor for the development of lymphocytes, and it is absolutely necessary for γδ T cells. Mice deficient in L-7 have a deficit of B and αβ T lymphocytes, and an absence of mature γδ TCR cells. IL-7 is essential for the survival, development and maturation of Schistosoma sp., although its production is associated with protection against intestinal helminths. The presence of anti-Anisakis simplex antibodies, especially IgA, is related to a lower frequency in CD3 + CD56 + αβ + lymphocytes and all subpopulations of γδ T cells. In this work, the relationship of IL-7 with humoral and cellular responses against A. simplex in 100 healthy subjects was studied. We have found significantly higher IL-7 levels in anti-A. simplex IgA-positive subjects (p < 0.001). The positivity of anti-A. simplex IgA was associated with a significant reduction in the frequency of CD3 + αβ+ (p < 0.01), CD3 + CD4 + αβ+, CD3 + CD8 + αβ+, CD3 + CD56 + αβ+, CD3 + γδ+, CD3 + CD4-CD8-γδ+ and CD3 + CD56 + γδ+ (p < 0.05) cells. In the case of NKT cells, this same phenomenon was also associated with IgE positivity. There was a weak inverse correlation (Spearman) of IL-7 levels with the frequencies of CD3 + CD4 + αβ+ (-0.125, p = 0.047), CD3 + CD8 + αβ+ (-0.204, p = 0.032), CD3 + CD56 + αβ+ (-0.247, p = 0.007), CD3 + γδ+ (-0.267, p = 0.007), CD3 + CD4-CD8-γδ+ (-0.266, p = 0.003), and CD3 + CD8 + γδ + (-0.302, p = 0.002) cells. The role of NKT cells in the anti-A. simplex response was confirmed and an association between IL and 7 levels and specific antibodies, especially IgA, was demonstrated. The higher production of IL-7 would represent a compensatory mechanism in response to the reduction in lymphocyte populations associated with the response against this parasite.