Clinical presentation of lesions (Patient 1).

<p>A: Initial ulcerated lesion at the right arm, reaching from the elbow to the forearm. B: Nodule1 appearing on the back, 275 days after end of antibiotic treatment. Both, nodule 2 on the thorax (C) and an ulcerated plaque on the right shoulder (D) had appeared 409 days after completion of antibiotic treatment.</p

Presence of B-cell clusters in the secondary lesions.

<p>A: Band of CD20 positive B-cells in sections of ulcer 2 of patient 1. B–E: serial sections of nodule 3 of patient 2 with a small dense cluster of CD20 positive B-cells (B) surrounded by CD14 positive macrophages/monocytes (C) and few interspersed CD3 positive T-cells (D) from which the majority was CD8 negative (E). Higher magnification (F–I) revealed a very dense package of the B-cells.</p

Bands of leucocytes surrounding an uninfiltrated necrotic area.

<p>Serial sections of nodule 2 of patient 1 with a necrotic area surrounded by a belt of CD14 positive monocytes/macrophages (A) and a more external second belt of CD3 positive T-cells (B). The necrotic core contained N-elastase positive neutrophilic debris (C), but no intact neutrophils (D insert). Clusters of CD20 positive B-cells were found away from the necrotic core (D).</p

Histopathological presentation of secondary lesions.

<p>Histological sections (nodule 2 of patient 2) were stained either with Ziehl-Neelsen (counterstain methylenblue; A, F, G) or with antibodies against cell surface or cytoplasmic markers (counterstain haematoxylin; B–E). A: Overview over excised tissue specimen revealing typical BU pathology features like fat cell ghosts, necrosis, epidermal hyperplasia and AFB (region 2) as well as a strong mixed infiltration typically observed in successfully treated BU lesions (region 1). B: CD14 staining of macrophages/monocytes; C: CD3 staining of T-cells; D: Elastase staining of neutrophils. In the necrotic region 2 large numbers of elastase-positive neutrophilic debris (E) and small clumps of AFB (F) with a beaded appearance (G) were observed.</p

Features of skin lesions that emerged after completion of antibiotic treatment.

<p>Lesions from which tissue samples became available for histopathological analysis are written in bold letters.</p

Characteristics of the 12 Buruli ulcer plaque patients.

<p>*the mean duration from start of treatment to ulceration was 30 days (11–53 days) for those five patients for which beginning of ulceration could be exactly recorded.</p

Characteristic histopathological features of tissue samples taken before start of antibiotic treatment.

<p>Histological sections were stained either with Haematoxylin-Eosin (HE) (A, C–E), Ziehl-Neelsen (counterstain methylenblue) (ZN) (B) or with antibodies against cell surface or cytoplasmic markers (counterstain haematoxylin) (F–H). A: Punch biopsy with large necrotic areas, fat cell ghosts and oedema but relatively intact epidermis and dermis. B: a band of extracellular AFBs is present in a deep layer of the necrotic subcutis. C: epidermis and dermis. D: necrotic region with fat cell ghosts. E: few infiltrating cells around a blood vessel. F: N-elastase staining revealed the presence of neutrophilic debris inside the necrotic regions. G: few intact neutrophils and H: CD68 positive infiltrating macrophages were found.</p

Characteristic histopathological features of tissue surgically excised to support wound healing.

<p>Histological sections were stained either with Haematoxylin-Eosin (HE) (A–C), Ziehl-Neelsen (counterstain methylenblue) (ZN) (L) or with antibodies against cell surface or cytoplasmic markers (counterstain haematoxylin) (D–K). A: Overview over an excised tissue specimen still harbouring large necrotic areas with fat cell ghosts and oedema. B: Overview over an excised tissue specimen presenting with mixed infiltration in the former necrotic region. C: Necrosis and oedema of the dermis of an excised non-ulcerative lesion. D: CD14 (D1) and N-elastase (D2) staining revealing a clear border between infiltration with intact CD14 positive macrophages (D1) and neutrophilic debris inside the necrotic area (D2). Infiltrated tissue areas contained large numbers of CD68 positive macrophages (E) and large numbers of CD3 positive cells (F). These belonged mainly of the CD8 (G) and not of the CD4 (H) subset. Langhans and foreign body giant cells (I) and B-cell cluster (J) were present in the majority of the samples. Accumulations of N-elastase positive cells (K) were occasionally found. AFB were rare, had a beaded appearance and intracellular location (L).</p

Characteristic histopathological features of tissue samples taken 26–34 days after start of antibiotic treatment.

<p>Histological sections were stained either with Haematoxylin-Eosin (HE) (A, B, H), Ziehl-Neelsen (counterstain methylenblue) (ZN) (C) or with antibodies against cell surface or cytoplasmic markers (counterstain haematoxylin) (D–G, I). A: Punch biopsy with large necrotic areas, fat cell ghosts and oedema but relatively intact epidermis and dermis. B: Higher magnification of necrotic tissue with large numbers of fat cell ghosts. C: Small numbers of intra and extracellular beaded AFB. D: N-elastase positive intact neutrophils were rare. E: More intact CD68 positive macrophages and F: CD3 positive T-cells were observed in the dermal tissue. Additionally, small CD20 positive B-cell cluster (G), few granulomas (H) and langhans giant cells (I) were found in only few of the samples.</p

participants in impact evaluation interviews.

<p>participants in impact evaluation interviews.</p