Estimation of serum level of interleukin-17 and interleukin-4 in leprosy, towards more understanding of leprosy immunopathogenesis.

Background: Combating Mycobacterium leprae is known to be via T-helper1 response. However, other T-helper effector cells; T-helper17 and T-helper2; play a role, particularly in the context of disease type. Aims: We aimed to evaluate serum levels of interleukin (IL)-17 (T-helper17 cytokine) and IL-4 (T-helper2 cytokine) in untreated patients with different types of leprosy, compared to controls. Methods: Using enzyme-linked immunosorbent assay, serum IL-17 and IL-4 levels were estimated in 43 leprotic patients and 43 controls. Patients were divided into six groups; tuberculoid, borderline cases, lepromatous, erythema nodosum leprosum (ENL), type 1 reactional leprosy, and pure neural leprosy. Patients were also categorized according to bacillary load and the presence or absence of reactions. Results: Serum IL-17 was signifi cantly lower in cases (4-61.5 pg/mL; median 19), compared to controls (26-55 pg/mL; median 36) (P < 0.001), and was signifi cantly lower in each type of leprosy compared to controls, with the lowest level in lepromatous leprosy (4-61.5 pg/mL; median 12.5). Signifi cantly elevated serum IL-4 was found in patients (1.31-122.4 pg/mL; median 2.31) compared to controls (1.45-5.72 pg/mL; median 2.02) (P = 0.008), with the highest level among lepromatous leprosy patients (2-87.2 pg/mL; median 28.9), and the lowest in type 1 reactional leprosy (1.4-2.5 pg/mL; median 1.87) (P = 0.006). Conclusion: Defective secretion of IL-17 is related to disease acquisition as well as progression toward lepromatous pole in leprosy patients. The overproduction of IL-4 in patients with lepromatous leprosy may infer their liability to develop ENL. Nevertheless, the small number of the studied population is a limitation.

Multiple isolated cutaneous plexiform schwannomas.

Plexiform schwannoma is a rare neurogenic tumor, arising from skin and subcutaneous tissue. The presence of multiple schwannomas suggests a possible association with neurofibromatosis type 2 (NF2). A 50-year old male patient presented with multiple papulo-nodular cutaneous lesions on both arms and forearms. Histopathological examination revealed a dermal multinodular pattern of well-circumscribed masses of closely packed cells, with peripheral myxoid tissue, well-encapsulated in a thin collagenous capsule. S-100 immunohistochemical staining was diffusely and strongly positive. Neuron-specific enolase was positive, confirming a neural tissue tumor. An audiogram and Magnetic Resonance Imaging (MRI) of cerebro-pontine angle showed no detected abnormality, excluding acoustic neuroma. Thus, we present a case of multiple bilateral isolated cutaneous plexiform schwannomas, not associated with NF2. Multiple plexiform schwannomas is a very rare entity, distinct from neurofibromatosis (NF), and being confined to the dermis is even more rarely reported.