Transcription of interleukin 31 and its receptor by leukocytes after Culicoides sp stimulation is dose dependent but is not exaggerated in allergic horses or correlated with pruritus

OBJECTIVE

Preliminary evidence supports a role for IL-31 in equine insect bite hypersensitivity (IBH) and pruritus. Our studies investigated IL-31 and IL-31 receptor-α (IL-31RA) transcription in leukocytes from normal and IBH horses in response to Culicoides nubeculosus.

ANIMALS

19 normal and 15 IBH horses were recruited in the summer of 2019 (low-dose study) and 8 normal and 10 IBH horses in the winter of 2022 to 2023 (high-dose study). Normal horses had no history or signs of allergic skin disease, while IBH horses had a history and clinical signs compatible with IBH. Pruritus was scored using a visual analog score or a 1 to 6 grading system.

PROCEDURES

Whole blood leukocytes were incubated with saline (0.9% NaCl) solution or C nubeculosus (0.26 µg/mL [low dose]; 5 μg/mL [high dose]). Transcription of IL-31 and IL-31RA was measured by quantitative RT-PCR.

RESULTS

Transcription of IL-31 and IL-31RA significantly increased in leukocytes from normal and IBH horses following high-dose C nubeculosus, and no differences were found between populations. Following low-dose C nubeculosus IL-31RA, transcription was increased in both normal and IBH horses, but IL-31 transcription was reduced in normal horses. No positive correlation was found between pruritus scores and IL-31 transcription after low- or high-dose C nubeculosus stimulation.

CLINICAL RELEVANCE

Exaggerated IL-31 transcription was not identified in IBH horses, suggesting that dysregulation in IL-31 signaling occurs downstream or in localized tissues or involves regulation by yet unidentified receptor splice variants or IL-31-induced increased sensitivity to other pruritogens. Further studies to understand IL-31 signaling in equine allergic skin disease are needed.

Cytokine expression in naïve and previously infected lambs after challenge with Teladorsagia circumcincta

Infection of sheep with Teladorsagia circumcincta triggers an immune response with predominantly type-2 (Th2) characteristics, including local eosinophila, mastocytosis and increased mucus production. In order to better understand the protective immune responses elicited, we used RT-PCR assays to define the changes in expression levels of a range of cytokine transcripts in lymph nodes draining the ovine abomasum following a challenge infection with T. circumcincta. This study compared the changes in cytokine expression in the abomasal lymph node following challenge with T. circumcincta in naïve sheep (Group 2) and sheep immunised by a previous trickle infection (Group 3), in comparison to unchallenged naive sheep (Group 1). There was a significant up-regulation of interleukin-4 (IL-4), IL-5 and IL-13 in both the challenged groups compared to naïve individuals. There was also an up-regulation of IL-1beta, IL-6, IL-10, IL-18, transforming growth factor-beta1 (TGFbeta1) and tumour necrosis factor-alpha (TNFalpha) by day 5 after infection. IL-12p40 was found to be increased in the previously infected Group 3 animals by day 5 following challenge. By contrast, transcription of this cytokine was found to be reduced by day 10 following infection of Group 2 animals. Expression of IL-2 and Interferon-gamma (IFNgamma) did not significantly differ between the three groups.

Parental investment and child health in a Yanomamö village suffering short-term food stress

The 1998 El Niño significantly reduced garden productivity in the Upper Orinoco region in Venezuela. Consequently, parents were forced to allocate food carefully to their children. Nutrition data collected from village children combined with genealogical data allowed the determination of which children suffered most, and whether the patterns of food distribution accorded with predictions from parental investment theory. For boys, three social variables accounted for over 70% of the variance in subcutaneous fat after controlling for age: number of siblings, age of the mother's youngest child, and whether the mother was the senior or junior co-wife, or was married monogamously. These results accord well with parental investment theory. Parents experiencing food stress faced a trade-off between quantity and quality, and between investing in younger versus older offspring. In addition, boys with access to more paternal investment (i.e. no stepmother) were better nourished. These variables did not account for any of the variance in female nutrition. Girls' nutrition was associated with the size of their patrilineage and the number of non-relatives in the village, suggesting that lineage politics may have played a role. An apparent lack of relationship between orphan status and nutrition is also interesting, given that orphans suffered high rates of skin flea infections. The large number of orphans being cared for by only two grandparents suggests that grooming time may have been the resource in short supply.

Multiple periorbital cutaneous myxomas progressing to scleromyxedema

Myxomas are rare cutaneous tumors that have been associated with a variety of other abnormalities including atrial myxomas, endocrine abnormalities, and bone malformations. We describe a 38-year-old white man with multiple periorbital myxomas in whom myalgias, fatigue, and more diffuse cutaneous involvement developed. These findings were consistent with scleromyxedema. He also had an associated left subclavian deep venous thrombosis. The patient responded well to therapy with cyclophosphamide.

Disseminated Rhizopus infection in a premature infant

A 16-day-old premature male infant developed rapidly expanding necrotic facial plaques. Histology and cultures of tissue biopsy specimens revealed infection with Rhizopus arrhizius. The patient was treated aggressively with surgical debridement, amphotericin B, and rifampin, but had a progressive spread of the cutaneous infection and a fatal clinical course. He had gastrointestinal and pulmonary involvement on autopsy. Zygomycoses are rapidly progressive infections which generally affect immunocompromised hosts. Premature infants should be included as individuals at risk for disseminated zygomycotic disease.