Follicular Infiltration Research Articles

Reflectance confocal microscopy of facial neoplasms: Follicular involvement as a clue to diagnosis.

Facial skin is characterized by high density of follicles. Facial neoplasms may present overlapping clinical and dermoscopic findings. Our goal was to evaluate and compare, via reflectance confocal microscopy (RCM), follicular involvement in facial neoplasms. We retrospectively searched our image database, between January 2008 and December 2020, for all facial lesions with (1) a standardized set of clinical, dermoscopic, and RCM images, and (2) a biopsy-proven diagnosis of lentigo maligna/lentigo maligna melanoma (LM/LMM, n= 39), basal cell carcinoma (BCC, n= 51), squamous cell carcinoma in situ (SCCIS, n= 5), actinic keratosis (AK, n= 11), and lichen-planus-like keratosis (LPLK, n= 18). Two readers jointly evaluated the RCM images for a set of predefined features of follicular involvement. Diffuse obliteration of follicles was frequent in BCC (88%), while follicular infiltration by refractile dendritic cells and/or by bright round nucleated cells was common in melanoma (90% and 44%, respectively). Extension of atypical keratinocytes down follicles was more prominent among SCCIS than AK (80% vs. 45%, p= 0.01). In most LPLK (89%), there was follicular sparing. Evaluation of RCM criteria centering on the follicles can be useful in the differential diagnosis between common facial neoplasms.

A retrospective study of 20 patients with Kimura’s disease from China

Background Kimura’s disease (KD) is an eosinophilic proliferative lymphoid disease with rare incidence rate and nonspecific clinical symptoms. Objectives To investigate the clinical characteristics, diagnosis, treatment, and prognosis of KD. Materials and methods The clinical manifestations, laboratory examination, imaging examination, proposed treatment, and prognosis of 20 patients with KD treated in our hospital were retrospectively analyzed. Results All cases showed painless masses. The proportion of peripheral blood eosinophils rose in 18 cases (90%), the eosinophil count increased in 14 cases (70%) and the serum immunoglobulin E (IgE) levels were significantly increased in 5 patients (100%). Pathological examination revealed follicular hyperplasia, eosinophils infiltration, and tiny vessels proliferation in KD samples. Conclusions KD should be considered when the patients suffered head and neck subcutaneous painless mass, increased peripheral blood eosinophils and raised serum IgE level. Pathological examination is the golden standard for diagnosing KD. Surgical intervention, medical treatments, and radiotherapy may be effective for KD treatment. Significance This study might shed a light on improving the diagnosis and treatment for KD.

Clinicopathological Spectrum of Cutaneous Lymphomas and Distinction of Early Mycosis Fungoides from its Mimics-A Retro-Prospective Descriptive Study from Southern India.

Cutaneous lymphomas (CLs) could be either primary (PCL) or secondary; the former comprises cutaneous T-cell lymphomas (CTCLs) and cutaneous B-cell lymphomas (CBCLs). Mycosis fungoides (MF) is the most common PCL. Diagnosis of early MF and distinguishing it from benign inflammatory mimics is challenging. This study aims to assess the clinicopathological spectrum of CL and to characterize early MF from its mimics using clinical characteristics, histopathological features, and ancillary techniques. This retro-prospective descriptive study was conducted in a tertiary-care institute, for over 5 years. Clinically as well as histopathologically suspected and biopsy-proven CL and their mimics were included. Cases were reviewed and subgrouped based on clinical and histopathological parameters and immunohistochemistry (IHC). Data were analyzed using descriptive statistics and a Chi-square test at a 5% level of significance. Among PCL, CTCL comprised 84% (21/25) and CBCL was 16% (4/25); the most common CTCL was MF at 81% (17/21). Histologically, atypia of dermal infiltrate (100%), epidermotropism (91.7%), basal alignment of lymphocytes (91.7%), clear haloed cells (91.7%), wiry collagen (66.7%), grandiosity sign (50%), eccrine infiltration (66.7%), and follicular infiltration (50%) were significantly associated with early MF. Spongiosis (84.6%), pigment incontinence (84.6%), exocytosis (76.9%), and parakeratosis (76.9%) were significantly associated with inflammatory mimics. There was no significant difference in the downregulation pattern of CD7 (P = 0.206) between early MF and its mimics. The four cases of CBCL in our study were plasmablastic lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, and lymphoblastic lymphoma. MF was the most common PCL. Histological parameters showed a significant difference, whereas IHC did not show any significant difference between early MF and its mimics.

Effects of vitamin B12 on rat ovary with ischemia-reperfusion injury

ABSTRACT We investigated the histopathological and biochemical effects of vitamin B12 on ischemia-reperfusion (I-R) injury using a rat ovarian torsion-detorsion model. We used four groups of female Wistar albino rats. Group 1 (sham group): both ovaries were removed. Group 2 (torsion group): ovarian torsion was established. Group 3 (torsion-detorsion group) perfusion was retored after ischemia for 2 h. Group 4 (torsion-detorsion-vitamin B12 group): after 2 h ovarian torsion, perfusion was re-established and 4 mg/kg vitamin B12 was administered for 2 h. Follicular degeneration, vascular congestion, hemorrhage, edema and infiltration were evaluated histologically. Tissue damage was decreased in group 4 compared to groups 2 and 3. Total antioxidant status TAS), total oxidant status (TOS) and malondialdehyde (MDA) level were measured. The values for TOS and MDA for groups 1 and 4 were similar. We found a significant increase in MDA and TOS levels in group 3 compared to group 2. MDA and TAS levels decreased and TOS levels were increased in group 4 compared to groups 2 and 3. MDA, TAS and TOS values were increased in groups 2 and 3 compared to group 1. We found that vitamin B12 reduced I-R damage in the rat ovary.

Folliculotropism in pigmented facial macules: Differential diagnosis with reflectance confocal microscopy.

Pigmented facial macules are common on sun damage skin. The diagnosis of early stage lentigo maligna (LM) and lentigo maligna melanoma (LMM) is challenging. Reflectance confocal microscopy (RCM) has been proven to increase diagnostic accuracy of facial lesions. A total of 154 pigmented facial macules, retrospectively collected, were evaluated for the presence of already-described RCM features and new parameters depicting aspects of the follicle. Melanocytic nests, roundish pagetoid cells, follicular infiltration, bulgings from the follicles and many bright dendrites and infiltration of the hair follicle (ie, folliculotropism) were found to be indicative of LM/LMM compared to non-melanocytic skin neoplasms (NMSNs), with an overall sensitivity of 96% and specificity of 83%. Concerning NMSNs, solar lentigo and lichen planus-like keratosis resulted better distinguishable from LM/LMM because usually lacking malignant features and presenting characteristic diagnostic parameters, such as epidermal cobblestone pattern and polycyclic papillary contours. On the other hand, distinction of pigmented actinic keratosis (PAK) resulted more difficult, and needing evaluation of hair follicle infiltration and bulging structures, due to the frequent observation of few bright dendrites in the epidermis, but predominantly not infiltrating the hair follicle (estimated specificity for PAK 53%). A detailed evaluation of the components of the folliculotropism may help to improve the diagnostic accuracy. The classification of the type, distribution and amount of cells, and the presence of bulging around the follicles seem to represent important tools for the differentiation between PAK and LM/LMM at RCM analysis.

Immunohistochemical changes of maxillary sinus mucosa with underlying adenomatous polyposis

Introduction In maxillary sinusitis pathogenesis researchers paid much attention to the role of paranasal sinuses, sinus drainage dysfunctions, mucocyliary transport system disorders in cases of damage of sinuses mucous membranes. Pathohistological, immunohistochemical and morphometric studies of mucosa were conducted. However, to evaluate the local inflammatory response in cases of chronic sinusitis and improvement of individual therapy for the patients, the immunohistochemical studies of the composition of inflammatory immunocyte infiltrates of paranasal sinus mucosa and adenoid vegetations bioptate would be reasonable.The aim of the research was to study the immunohistochemical content of immunocyte infiltrates of paranasal sinuses adenomatous polyps in biopsy samples of patients suffering from chronic sinusitis.Materials and Methods. Paranasal sinuses adenomatous polyps removed during surgery of 22 patients suffering from chronic maxillary sinusitis were studied. Immunohistochemical studies of paraffin sections of the removed polyps were performed using appropriate primary antibodies and visualization systems DAKO EnVision+ System (DAKO, Denmark).Results. During microscopic investigation of paranasal sinuses adenomatous polyps of the patients suffering from chronic sinusitis, moderate and severe immunocyte infiltration of polyp stroma sometimes with focal follicular structures was presented. Immunohistochemical investigation of the cellular composition of these infiltrates proved the presence of CD8+ T-killer cells, CD4+ T-helper cells, CD68+ macrophages as well as single plasma cells. The irregularity of these cells markers expression was determined in dependence of the severity of inflammatory cell infiltration.Conclusions. In the patients with chronic maxillary polyp sinusitis with mild and moderate immunocyte infiltration of paranasal sinus mucosa, among immune cells the CD4+ T-lymphocytes occupied the most relative area in polyp stroma, plasma cells – the least (р < 0.001). In the patients with significant immunocellular infiltration in immunocyte follicular infiltration of polyp stroma the relative area of CD4+ and CD8+ T-lymphocytes significantly exceeded the relative area of macrophages and plasma cells.

An immunohistochemical analysis of lymphocytic infiltrations in canine skin cancers.

Lymphocytic infiltrations located in the extracellular matrix often accompany canine skin cancer. They can be characterised as an inflammatory infiltration and/or a second tumour - lymphoma. The aim of this study was an immunohistochemical analysis of a lymphocytic infiltration which accompanies spontaneous skin cancer. Twenty basal cell carcinoma, 20 non-keratinizing squamous cell carcinoma, 20 keratinizing squamous cell carcinoma and 8 sebaceous gland carcinoma samples which were accompanied by a lymphocytic infiltration and/or secondary lymphatic follicles were verified histopathologically. The expression of bcl-2, CD3, CD79α, Ki-67, MCM-3 and MCM-7 in the lymphocytic infiltration was evaluated. Four types of lymphocytic infiltrations were found: I - diffuse bcl-2+, II - diffuse bcl-2-, III - follicular bcl-2+/- where the centre was bcl-2-, and the marginal zone of the follicles and the extrafollicular area were bcl-2+ and IV - aggregated bcl-2+, where the centre and periphery were bcl-2+. The I and IV type corresponds to lymphoma, II type is non-neoplastic immune response and III type suggest reactive follicular hyperplasia. The proliferation of lymphocytes which demonstrated the expression of neoplastic markers (I and IV), suggests preneoplastic phase (pseudolymphoma) or lymphoma - the second independent tumour. A high proliferative index of the follicular blc-2+/- follicular infiltration indicates an increased immunological response of the host against skin cancer.

Which Skin Lupus Criteria are of More Value in Determining the Disease: A Greater View with the Help of Direct Immune Fluorescent (DIF)

Background: Lupus erythematous (LE) describes a spectrum of auto immune disorders, involving whole body (systemic LE) in one end and cutaneous limited LE on the other side. Cutaneous LE mainly diagnosed via clinical manifestations as well as histopathologic examination. According to different pathologic specifications, the aim of present study was to determine which histopathologic criterion is more accurate and practical in diagnosing cutaneous LE. Material and Methods: Samples taken from patients with clinical manifestations of Cutaneous LE with pathologic confirmation, included. All patients had direct immuno fluorescent (DIF) samples that recorded. Histopathologic findings are categorized into three groups: group 1 contains epidermal changes, group 2 includes interface changes and group 3 contains dermal changes. Different histopathologic finding such as perivascular infiltration, follicular atrophy, follicular plaque, and basements membrane thickness and other changes, as well as DIF patterns, were recorded in designed questionnaires to further analysis with SPSS software. Results: Of 145 patients (61.4% female and 38.6% male) in 58.6% DLE was the first clinical diagnosis,23% was the second and in subsequent 4.1%, 1.4% and 0.7% was third, fourth and fifth diagnosis respectively. In 11% of caeses DLE was not among clinical impressions. DIF was positive in 49%. As a whole, superficial perivascular and perifolicular infiltration were observed in 99% of the cases and was the commonest pathologic feature followed by basal vacuolization, peri follicular infiltration and epidermal atrophy. Other pathologic changes were observed with variable rates. Discussion: By grouping histopathologic criterion, it seems that hyperkeratosis and thickening of Basement membrane may be major histologic criterion and peri vascular infiltration, peri follicular infiltration and eccrine gland infiltration, may be minor.

Reactive follicular lymphoid infiltrate: A new condition to exclude in patients with PET positivity inside the heart

Reactive follicular lymphoid infiltrate: A new condition to exclude in patients with PET positivity inside the heart

Folliculotropic mycosis fungoides with extreme pilosebaceous involvement and hematological abnormalities

Folliculotropic mycosis fungoides (fMF) has been defined as a variant of MF with follicular infiltration of atypical lymphoid cells, sparing the interfollicular epidermis [1-4]. We report two patients with fMF who presented with a variety of pilosebaceous manifestations and elevated CD4/CD8 ratios and showed distinct clinical courses.A 65-year-old woman presented with a 6-month history of multiple, discrete, reddish papules and comedones on the face. On examination, numerous reddish, follicular papules [...]

Unklare asymptomatische infiltrierte Papeln im Gesicht eines HIV-infizierten Mannes

A 65 year old HIV-infected patient (CDC A2, diagnosed in 07/2008) presented with facial, erythematous infiltrated papular lesions. Consistent with progressive immunodeficiency a low CD4+ T-cell count and an increase of the viral load was seen simultaneously and an eosinophilic pustular folliculitis (EPF) was assumed. Though, the lesional biopsy revealed a follicular eosinophilic infiltration and endotrichial hyphae, proving for an infiltrating dermatophytosis. This shows how an infiltrating Tinea faciei is mimicking clinically and histologically an HIV-associated EPF of the face.

21. Peripheral T-cell lymphoma with follicular pattern: a ‘real’ entity

Peripheral T-cell lymphoma (PTCL) with a follicular pattern of growth is a rare condition with a few cases described in the literature. According to the World Health Organization classification, cases of PTCL with a follicular pattern are included in the category of unspecified PTCL. We report a case of PTCL with a prominent bilateral inguinal lymphadenopathy from a 71-year-old man. Microscopic examination of the lymph node identified effacement of the nodal architecture by a nodular, follicular infiltrate extending across the capsule. The follicular compartment was composed of a mixture of cells including small lymphocytes, and small and large lymphoid cells with round or irregular hyper-chromatic nuclei resembling centrocytes, centroblasts and immunoblasts. Immunohistochemical stains revealed that the follicles contained mostly T-cell type cells with co expression of CD3, CD4 and CD5. This was also confirmed by flow cytometry showing the most of the cells to be CD4 positive T cells. The Ki67 indicated a proliferation index around 10%. CD20 staining showed residual B-cells within the follicular areas suggesting that the tumour had colonised lymphoid follicles. Molecular studies confirmed a monoclonal T-cell receptor γ gene rearrangement. The bone marrow aspiration and biopsy were unremarkable. This case demonstrates the importance of considering the diagnosis of PTCL in lesions with a nodular pattern of growth, particularly in view of the different prognostic features and treatment modalities for T-cell and B-cell neoplasms.

Pink plaque on a teenager's face

An 18-year-old otherwise healthy female presented with a 1-month history of an enlarging and mildly pruritic lesion on her face. She had noted the presence of clear material oozing out when she squeezed the area. The physical examination revealed a 15-mm pink plaque on her left upper cutaneous lip, with slight accentuation around the hair follicles (Fig 1, A). The rest of her cutaneous examination was normal. An incisional biopsy specimen revealed follicular structures filled with mucin (Fig 1, B), highlighted by a colloidal iron stain (Fig 1, C) and a mild lymphocytic follicular infiltrate.

Expression of Bcl-2 and Bax Proteins in Thyroid Glands of Rats in Experimental Thyroiditis

In the recent years, iodine was associated to the development of apoptosis in thyroid diseases. The aim of the present study is to determine the expression of pro-apoptotic and anti-apoptotic proteins, Bax and Bcl-2, in a Wistar rat experimental model of thyroiditis induced by administration of different doses of potassium iodide. Immunohistochemical staining was done with chromogen diaminobenzidine on avidin-biotin peroxidase using the Animal Research Kit (ARK), stained with antibodies to Bcl-2 and Bax proteins. The intensity and distribution of positive staining were evaluated by light microscopy on a scale of 0 to 4. Bax protein was expressed in the area of regenerating follicular cells in high percent in potassium iodide treated rats, but was not expressed in thyrocytes from control rats. Bcl-2 expression was constantly observed in thyrocytes of the control group and in the mantle-zone of lymphoid follicular infiltrates. Our results show that Bax expression is significantly higher in the Wistar rat experimental model of thyroiditis than in the control group. These data suggest that the increased expression of Bax may contribute to the role of apoptosis in the pathogenesis of experimental thyroiditis.

Follikuläre Mykosis fungoides – Behandlung mit Methotrexat, Interferon-alpha, PUVA und Dermabrasio

Follicular mycosis fungoides is a special type of cutaneous T-cell lymphoma, characterized by a primary follicular infiltration by the malignant T-cells. It is a rare disease pattern and especially in the early stage often remains unidentified. Clinically, follicular papules and plaques with follicular plugging as well as aggregates of cysts and comedones are characteristic. In our patient, the diagnosis was established three years after the onset of cutaneous lesions. Using surgical procedures as well as a complex drug regimen including methotrexate and interferon-alpha we could achieve a highly satisfying outcome so far.

Histological differentiation of skin toxicity between cetuximab, erlotinib and panitumumab (single ErbB1) and lapatinib (dual ErbB1/2) epidermal growth factor receptor inhibitors

e20617 Background: Epidermal growth factor receptor inhibition by monoclonal antibodies and tyrosine kinase inhibitors has demonstrated activity in solid tumors. However, blockade of EGFR in skin results in disabling skin toxicity that may lead to therapeutic dose modification or interruption. This study compares cutaneous histological alterations among four EGFR inhibitors (EGFRIs): cetuximab (C), erlotinib (E), lapatinib (L) and panitumumab (P). Methods: Punch skin biopsies from patients with papulopustular rash were collected from 8 patients per each EGFRI (n=32). Two dermatopathologists performed independent blinded assessment of epidermis, dermis, follicle and inflammatory infiltrates. Histologic features were rated as 0 (absent) or 1 (present), with the exception of dyskeratosis, rated from 0 (absent) to 2 (severe) and infiltrate, rated from 0 (absent) to 3 (most prominent). Where variation occurred, scores were reconciled and combined for analysis. Results: Epidermal atrophy was observed for C, E, L and P (range 0–1, median 1, 1, 0, 0.5, respectively) and neutrophilic follicular infiltrate was observed for C, E, L and P (range 0–3, median 0.5, 3, 0, 3, respectively). Neutrophilic dermal infiltrate (range 0–3) and follicular neutrophilic pustules (range 0–1) were most prevalent in P (median 0.5), whereas the median for C, E and L was 0. A mononuclear dermal infiltrate (range 0–3) was least prevalent with C (median 0) while E, L and P had a median of 0.5. Concretions (range 0–1) were most prevalent for E (median 1), whereas the median for C, L and P was 0. Conclusions: Lapatinib, a dual ErbB1/2 inhibitor, induced the least structural disarray and inflammation in the skin as measured by median scores for epidermal atrophy, neutrophilic dermal and follicular infiltrates, neutrophilic pustules and lack of bacterial concretions. These histological data confirm a more benign pattern of rash with lapatinib compared to single ErbB1 inhibitors. [Table: see text]

Prolonged Bone Marrow Failure Following Rituximab Therapy of Follicular Lymphoma

Prolonged Bone Marrow Failure following Rituximab Therapy of Follicular Lymphoma Laura Debatin, Annette Schmitt-Graeff*, Hendrik Veelken Depts. of Hematology/Oncology and *Pathology, University Medical Center Freiburg Rituximab (R) is a mainstay in B-NHL therapy. Apart from infusional reactions and prolonged B cell depletion, severe R side effects are relatively rare. A 65 year-old, previously healthy woman presented with anemia (Hb 9.3 mg/dl), thrombocytopenia, and cervical lymphadenopathy. A submandibular lymph node biopsy showed CD20+CD10+CD79a+ follicular infiltrates. Diagnosis of follicular lymphoma was supported by detection of an IgH-BCL2 gene rearrangement by FISH. CT scans revealed generalized lymphadenopathy and hepatosplenomegaly. The BM was infiltrated with 68% clonal CD20+CD10+CD79a+ B cells. Due to advanced (stage IVA) and high-risk disease (FLIPI 4/5), 200 mg/m2 cyclophosphamide/100 mg prednisone/day (d) were given for 5 days, followed by a single dose of 375 mg/m2 R. Grade 4 neutropenia developed 4 days later and precluded the planned CHOP chemotherapy. A BM biopsy on d+21 post R showed marked BM hypoplasia consistent with drug-induced changes, but no residual lymphoma. Serologic testing ruled out Parvovirus B19, HBV, HCV and HIV infections. Leukocytes recovered to >1/nl 3,5 weeks after R administration. No further cytoreduction was given due to prolonged cytopenia and documented PR. Despite this history, Bendamustin/R (200 mg) was given for eventual BM relapse at a different hospital 11 months later. Grade 4, filgrastim-refractory cytopenia with the same BM histology developed promptly and lasted for 4 weeks. The patient was transferred to our institution because of multiple opportunistic infections including pulmonary aspergillosis, E. faecium sepsis, and destructive mucor mycosis of the right maxillary sinus. Posaconazole and liposomal amphotericin were given for 5 months. 13 months after the 2nd R infusion, the patient had to undergo reconstructive surgery with a flap plasty to cover an extensive, disfiguring facial and maxillary necrosis. Since different alkylators were given at moderate doses, a causal relationship to similar episodes of rapid-onset, extended BM failure appears unlikely. R, administered immediately prior to both episodes, appears to be the causative agent in this case. Since hematopoietic precursors and the myeloid lineage do not express CD20, the mechanism for this near-fatal BM failure is unknown and suggestive of an idiosyncratic component. The BM findings are incompatible with a metamizol-type allergic agranulocytosis. Severe BM failure appears to be a rare but grave potential side-effect of rituximab.

Merkel Cell Carcinoma With a Follicular Lymphocytic Infiltrate: Report of 2 Cases

Merkel cell carcinoma (MCC) with a follicular lymphocytic infiltrate of the dermis was first reported by Bastian et al in 1996. Thereafter there were no further reports of such a morphological variant of MCC. We present here 2 cases of MCC characterized by foci of a dense lymphocytic infiltrate with the formation of lymphoid follicles. This feature may produce a potential diagnostic pitfall, rendering a lymphomatous appearance to the tumor.

Diagnosis and Management of Primary Cicatricial Alopecia: Part I

In this 2-part article, the authors review the primary cicatricial alopecias. Primary cicatricial alopecia can be defined as predominantly lymphocytic, neutrophilic, or mixed based on the nature of the follicular infiltrate that is present around affected hair follicles. Lymphocytic primary cicatricial alopecias include chronic cutaneous lupus erythematosus (discoid lupus erythematosus), lichen planopilaris, classic pseudopelade of Brocq, central centrifugal cicatricial alopecia, alopecia mucinosa, and keratosis follicularis spinulosa decalvans. In this first part, the authors summarize the classification, epidemiology, diagnostic approach, and patient management of lymphocytic cicatricial alopecias. In part II, the authors will focus on neutrophilic cicatricial alopecias and mixed cicatricial alopecias.

Limited pathogenicity of Usutu virus for the domestic chicken (Gallus domesticus)

In summer 2001, Usutu virus (USUV), a mosquito-borne flavivirus, was isolated for the first time in Europe during a mortality incident among Eurasian blackbirds (Turdus merula) in Austria. Chickens are frequently used as sentinel animals for arbovirus surveillance systems. In the present study, the pathogenicity of USUV for specific pathogen free chickens was investigated. Ten 2-week-old chickens were inoculated intravenously with 0.1 ml inoculum containing 10(3) median (50%) tissue culture infectious dose of USUV strain Vienna 2001-blackbird (939/01). Clinical signs, viraemia, gross and microscopic lesions, contact transmission and immunological response were evaluated. No clinical signs were observed in the USUV-inoculated animals during the experimental period. Pathological examination showed moderate splenomegaly and follicular infiltrates in the liver of several inoculated animals. Mild non-suppurative encephalitis was observed in the brain tissue of one virus-inoculated chicken examined 7 days post inoculation (d.p.i.). USUV nucleic acid was detected by reverse-transcriptase polymerase chain reaction in the organs of six inoculated chickens, although immunohistochemistry for flavivirus antigen was negative in all tissues from all chickens. Virus shedding was shown in three inoculated birds by detecting USUV RNA in cloacal swabs of two chickens at 5 d.p.i., and in the cloacal and pharyngeal swabs of one chicken at 7 d.p.i. Based on detection of viral RNA in peripheral blood mononuclear cells, viraemia was detected only in two chickens (at 7 d.p.i.). Only one of the inoculated chickens developed an antibody response. There was no evidence of virus transmission to chickens kept in contact with inoculated birds. No USUV was isolated from in-contact birds and all in-contact and control animals lacked USUV-specific antibodies. The present data suggest that domestic chickens are not at risk of developing clinical disease following USUV infection and that chickens are unlikely to be useful for sentinel purposes in USUV surveillance programmes.