Neutropenic Mice Provide Insight into the Role of Skin-Infiltrating Neutrophils in the Host Protective Immunity against Filarial Infective Larvae.

Our knowledge and control of the pathogenesis induced by the filariae remain limited due to experimental obstacles presented by parasitic nematode biology and the lack of selective prophylactic or curative drugs. Here we thought to investigate the role of neutrophils in the host innate immune response to the infection caused by the Litomosoides sigmodontis murine model of human filariasis using mice harboring a gain-of-function mutation of the chemokine receptor CXCR4 and characterized by a profound blood neutropenia (Cxcr4(+/1013)). We provided manifold evidence emphasizing the major role of neutrophils in the control of the early stages of infection occurring in the skin. Firstly, we uncovered that the filarial parasitic success was dramatically decreased in Cxcr4(+/1013) mice upon subcutaneous delivery of the infective stages of filariae (infective larvae, L3). This protection was linked to a larger number of neutrophils constitutively present in the skin of the mutant mice herein characterized as compared to wild type (wt) mice. Indeed, the parasitic success in Cxcr4(+/1013) mice was normalized either upon depleting neutrophils, including the pool in the skin, or bypassing the skin via the intravenous infection of L3. Second, extending these observations to wt mice we found that subcutaneous delivery of L3 elicited an increase of neutrophils in the skin. Finally, living L3 larvae were able to promote in both wt and mutant mice, an oxidative burst response and the release of neutrophil extracellular traps (NET). This response of neutrophils, which is adapted to the large size of the L3 infective stages, likely directly contributes to the anti-parasitic strategies implemented by the host. Collectively, our results are demonstrating the contribution of neutrophils in early anti-filarial host responses through their capacity to undertake different anti-filarial strategies such as oxidative burst, degranulation and NETosis.

Hodgkin's disease masquerading as fibrous thyroiditis: potential role of cytokines in in vivo and in vitro studies.

Hodgkin's disease appearing as, or associated with, fibrous thyroiditis has only been described rarely. We report the observation of a patient presenting with a goitre, fibrosis of the thyroid and adjacent structures, and hypothyroidism. The histological examination was compatible with fibrosclerotic thyroiditis. This diagnosis was reviewed 6 months later when the biopsy of a supraclavicular nodule that had subsequently appeared led to the diagnosis of a nodular-sclerosis type of Hodgkin's disease. The plasmatic levels of interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) were very high compared to the levels in healthy subjects (12 and 40 IU/l vs. 0.05 and 2.0 IU/l, respectively). These cytokine levels decreased when the initial illness was treated, and their normalization was associated with the disappearance of the cervical and thyroidal fibroses. A parallel in vitro study of these cytokines and of TNF-alpha receptors and IL-13 was performed. The results suggest a possible cause-and-effect relationship between IL-6 and IL-13 produced locally by the tumoral tissue and the development of cervical fibrosis.