CSL324, a granulocyte colony-stimulating factor receptor antagonist, blocks neutrophil migration markers that are upregulated in hidradenitis suppurativa.

BACKGROUND: Neutrophils have been shown to contribute to the pathophysiology of hidradenitis suppurativa (HS), a chronic, painful and debilitating inflammatory skin disease, yet their exact role remains to be fully defined. Granulocyte colony-stimulating factor (G-CSF), a major regulator of neutrophil development and survival, can be blocked by the novel, fully human anti-G-CSF receptor (G-CSFR) monoclonal antibody CSL324. OBJECTIVES: We investigated the activation and migration of neutrophils in HS and the impact of blocking G-CSFR with CSL324. METHODS: Biopsy and peripheral blood samples were taken from participants of two studies: 2018.206, a noninterventional research study of systemic and dermal neutrophils and inflammatory markers in patients with neutrophilic skin diseases, and CSL324_1001 (ACTRN12616000846426), a single-dose ascending and repeated dose, randomized, double-blind, placebo-controlled study to assess the safety, pharmacokinetics and pharmacodynamics of CSL324 in healthy adult subjects. Ex vivo experiments were performed, including neutrophil enumeration and immunophenotyping, migration, receptor occupancy and transcriptome analysis. RESULTS: The number of cells positive for the neutrophil markers myeloperoxidase (MPO) and neutrophil elastase (NE) was significantly higher in HS lesions compared with biopsies from healthy donors (HDs) (P < 0.0001 and P = 0.0223, respectively). In peripheral blood samples, mean neutrophil counts were significantly higher in patients with HS than in HDs (2.98 vs. 1.60 × 109 L-1, respectively; P = 8.8 × 10-4). Neutrophil migration pathways in peripheral blood were increased in patients with HS and their neutrophils demonstrated an increased migration phenotype, with higher mean CXCR1 on the surface of neutrophils in patients with HS (24453.20 vs. 20798.47 for HD; P = 0.03). G-CSF was a key driver of the transcriptomic changes in the peripheral blood of patients with HS and was elevated in serum from patients with HS compared with HDs (mean 6.61 vs. 3.84 pg mL-1, respectively; P = 0.013). Administration of CSL324 inhibited G-CSF-induced transcriptional changes in HDs, similar to those observed in the HS cohort, as highlighted by expression changes in genes related to neutrophil migratory capacity. CONCLUSIONS: Data suggest that neutrophils contribute to HS pathophysiology and that neutrophils are increased in lesions due to an increase in G-CSF-driven migration. CSL324 counteracted G-CSF-induced transcriptomic changes and blocked neutrophil migration by reducing cell-surface levels of chemokine receptors.

Secondary organizing pneumonia (bronchiolitis obliterans with organizing pneumonia) associated with adalimumab for treatment of chronic plaque psoriasis.

Organizing pneumonia is defined histopathologically by intra-alveolar buds of granulation tissue, consisting of intermixed myofibroblasts and connective tissue. The pathological pattern of organizing pneumonia may be idiopathic or related to a determined cause, termed secondary organizing pneumonia. We report a 68-year-old woman with a longstanding history of chronic plaque psoriasis, treated with the tumor necrosis factor (TNF) inhibitor, adalimumab. After 8 years of treatment, she developed a gradual-onset, non-productive cough with associated generalized fatigue and mild dyspnea. Radiological investigations demonstrated ground-glass opacities in the left lower lobe and bronchoscopy revealed a fibroinflammatory process consistent with organizing pneumonia. Her biologic treatment was ceased and corticosteroid treatment commenced, with resolution of both her symptoms and the radiological findings. Given the increasing incidence of biologic treatment in the management of dermatological conditions, clinicians should be aware of secondary organizing pneumonia as a possible side effect of TNF inhibitor therapy.

Docetaxel-induced nail dystrophy.

A 73-year-old man with metastatic prostate cancer treated with weekly docetaxel chemotherapy for 5 months developed an acute nail dystrophy restricted to the fingernails. This was characterized by onycholysis, subungual haemorrhage and acute paronychia, progressing to a subungual abscess of the right index finger. Nail bed hyperaemia and haemosiderin-like nail bed discoloration were present. Nail plate avulsion was performed to decompress the acutely painful subungual abscess. The right thumb, middle finger and left index finger demonstrated early, proximal white subungual collections of pus obscuring the lunula (onychophosis). Central nail plate fenestrations with a surgical drill led to exudation of purulent material. Cultures of the subungual abscess material yielded mixed organisms, possibly related to administration of flucloxacillin for 1 week prior to presentation. The patient completed a further two courses of docetaxel without sequelae, and the nail dystrophy appears to be resolving. Docetaxel-induced nail changes are a common adverse effect, occurring in 30-40% of patients. Mild changes do not usually warrant the discontinuation of treatment.