American cutaneous leishmaniasis: In situ immune response of patients with recent and late lesions

TNF-α, IFN-γ, IL-10, IL-17, CD68 and CD57 were evaluated in biopsies of patients with American cutaneous leishmaniasis living in Sorocaba, Brazil. The analyses were performed considering the time of lesions from 23 patients with recent lesions (Group I) and 19 patients with late lesions (Group II). All patients were infected with Leishmania (Viannia) braziliensis. Immunostaining cells for CD68, CD57, TNF- α, IFN-γ, IL-10 and IL-17 were performed by immunohistochemistry. Except for CD68 and IL-17, the distribution of in situ for CD57, IL-10, TNF-α and IFN-γ showed that patients with recent lesions expressed higher levels than those with late lesions. The comparison of cytokine expression/group showed that IL-10 was significantly higher than IL-17 and IFN-γ (similar data were shown in IL-17 compared with TNF-α), suggesting an immunological balance between inflammatory-anti-inflammatory agents. This balance was similar for two groups of patients. In conclusion, these data suggested that (i) patients from Group I had recent lesions (in the beginning of chronic phase) compared to those from Group II and (ii) the modulation of inflammatory response in patients with recent American cutaneous leishmaniasis was correlated with IL-10 expression in skin lesions preventing the development of mucosal forms. The parasite treatment also prevented the evolution of severe forms

American cutaneous leishmaniasis: In situ immune response of patients with recent and late lesions.

TNF-α, IFN-γ, IL-10, IL-17, CD68 and CD57 were evaluated in biopsies of patients with American cutaneous leishmaniasis living in Sorocaba, Brazil. The analyses were performed considering the time of lesions from 23 patients with recent lesions (Group I) and 19 patients with late lesions (Group II). All patients were infected with Leishmania (Viannia) braziliensis. Immunostaining cells for CD68, CD57, TNF- α, IFN-γ, IL-10 and IL-17 were performed by immunohistochemistry. Except for CD68 and IL-17, the distribution of in situ for CD57, IL-10, TNF-α and IFN-γ showed that patients with recent lesions expressed higher levels than those with late lesions. The comparison of cytokine expression/group showed that IL-10 was significantly higher than IL-17 and IFN-γ (similar data were shown in IL-17 compared with TNF-α), suggesting an immunological balance between inflammatory-anti-inflammatory agents. This balance was similar for two groups of patients. In conclusion, these data suggested that (i) patients from Group I had recent lesions (in the beginning of chronic phase) compared to those from Group II and (ii) the modulation of inflammatory response in patients with recent American cutaneous leishmaniasis was correlated with IL-10 expression in skin lesions preventing the development of mucosal forms. The parasite treatment also prevented the evolution of severe forms.

American cutaneous leishmaniasis: In situ immune response of patients with recent and late lesions

TNF­α, IFN­Î³, IL­10, IL­17, CD68 and CD57 were evaluated in biopsies of patients with American cutaneous leishmaniasis living in Sorocaba, Brazil. The analyses were performed considering the time of lesions from 23 patients with recent lesions (Group I) and 19 patients with late lesions (Group II). All patients were infected with Leishmania (Viannia) braziliensis. Immunostaining cells for CD68, CD57, TNF­ α, IFN­Î³, IL­10 and IL­17 were performed by immunohistochemistry. Except for CD68 and IL­17, the distribution of in situ for CD57, IL­10, TNF­α and IFN­Î³ showed that patients with recent lesions expressed higher levels than those with late lesions. The comparison of cytokine expression/group showed that IL­10 was significantly higher than IL­17 and IFN­Î³ (similar data were shown in IL­17 compared with TNF­α), suggesting an immunological balance between inflammatory­anti­inflammatory agents. This balance was similar for two groups of patients. In conclusion, these data suggested that (i) patients from Group I had recent lesions (in the beginning of chronic phase) compared to those from Group II and (ii) the modulation of inflammatory response in patients with recent American cutaneous leishmaniasis was correlated with IL­10 expression in skin lesions preventing the development of mucosal forms. The parasite treatment also prevented the evolution of severe forms.

TNF-α, IFN-γ, IL-10, IL-17, CD68 e CD57 foram avaliados em biópsias de pacientes com leishmaniose tegumentar americana residentes em Sorocaba, Brasil. As análises foram realizadas considerando o tempo de lesão de 23 pacientes com lesões recentes (Grupo I) e 19 pacientes com lesões tardias (Grupo II). Todos os pacientes foram infectados com Leishmania (Viannia) braziliensis. As células de imunocoloração para CD68, CD57, TNF-α, IFN-γ, IL-10 e IL-17 foram realizadas por imuno-histoquímica. Exceto para CD68 e IL-17, a distribuição in situ de CD57, IL-10, TNF-α e IFN-γ mostrou que pacientes com lesões recentes expressavam níveis mais altos do que aqueles com lesões tardias. A comparação da expressão / grupo de citocinas mostrou que a IL-10 foi significativamente maior que a IL-17 e IFN-γ (dados semelhantes foram mostrados na IL-17 em comparação com o TNF-α), sugerindo um equilíbrio imunológico entre agentes inflamatórios e anti-inflamatórios . Esse equilíbrio foi semelhante para dois grupos de pacientes. Em conclusão, esses dados sugeriram que (i) pacientes do grupo I apresentavam lesões recentes (no início da fase crônica) em comparação com os do grupo II e (ii) a modulação da resposta inflamatória em pacientes com leishmaniose tegumentar americana recente estava correlacionada com Expressão da IL - 10 em lesões cutâneas impedindo o desenvolvimento de formas mucosas. O tratamento do parasita também impediu a evolução de formas graves.

Pathology of congenital Zika syndrome in Brazil: a case series

Zika virus is an arthropod-borne virus that is a member of the family Flaviviridae transmitted mainly by mosquitoes of the genus Aedes. Although usually asymptomatic, infection can result in a mild and self-limiting illness characterised by fever, rash, arthralgia, and conjunctivitis. An increase in the number of children born with microcephaly was noted in 2015 in regions of Brazil with high transmission of Zika virus. More recently, evidence has been accumulating supporting a link between Zika virus and microcephaly. Here, we describe findings from three fatal cases and two spontaneous abortions associated with Zika virus infection.

Detection of Toxoplasma gondii in two southern Wooly spider monkeys (Brachyteles arachnoides-Geoffroy, 1806) from the Rio de Janeiro primate center, Brazil.

BACKGROUND: Toxoplasmosis led to the death of two Brachyteles arachnoides, an endangered atelid. METHODS: The diagnosis was established by necropsy, histopathological, immunohistochemical and ultrastructural changes. RESULTS: The analysis confirms the presence of Toxoplasma gondii. CONCLUSIONS: This report contributes to the development of protocols for health surveillance on maintenance and conservation of southern muriquis.

Toxoplasmosis in a Guiana dolphin (Sotalia guianensis) from Paraná, Brazil.

This study describes toxoplasmosis in a by caught Guiana dolphin (Sotalia guinensis) from Paranaguá Bay, Paraná, Brazil. Interstitial pneumonia, multisystemic arteritis, multifocal adrenalitis and hepatitis were the primary lesions observed. These tissues had moderate to severe necrosis and mononuclear cells infiltration usually surrounded by tachyzoites and tissue cysts. Moderate lymphoid depletion was evident in the spleen. Toxoplasma gondii was positive by immunohistochemical and ultrastructural evaluation. Furthermore, the animal was negative for Morbillivirus by immunohistochemistry and had low levels of persistent organochlorines. There is evidence of environmental changes in the Paranaguá Bay that could justify the occurrence of toxoplasmosis in Guiana dolphin. The sewage run-off from main urban areas and the presence of domestic and wild felids in areas surrounding the bay could be a source of T. gondii oocysts from land to sea. Based on its habitat, the authors recommend this dolphin species as sentinels for the health of bays and estuaries where they occur.

Transplacental transmission of Toxoplasma gondii in reinfected pregnant female canines.

Twelve pregnant female canines, naturally infected with Toxoplasma gondii, were reinfected with T. gondii: three (GI) received tachyzoites subcutaneously (1.0 x 107), three (GII) were orally inoculated with oocysts (1.5 x 104), and six (GIII) were kept as a nonreinfected control group. All the reinfected female canines (GI and GII) miscarried or presented fetal death, while only one GIII female presented a stillborn in a litter of four pups (P < 0.01). Fever, lymphoadenopathy, miscarriage, and fetal death were the main clinical alterations observed. The highest serological titers detected through the indirect fluorescence antibody test (IFAT) were 1,024 (GI) and 4,096 (GII). In group III, the titers ranged between 64 and 256. By bioassays in mice, T. gondii was isolated in 17 organs of the reinfected adult canines, in 11 of the control group, and in 20 of the neonates. Positive immunostaining of cysts and/or tachyzoites were observed in 26 canine tissues (14 from GI and GII and ten from GIII). The agent was detected by immunohistochemistry in the encephalon of a neonate and in the spinal cord of a stillborn, thus, confirming that T. gondii infected canine fetuses, provoking miscarriages, even in bitches that presented primoinfection.

Orbital (retrobulbar) meningioma in a Simmental cow.

A 12-year-old Simmental cow was presented with a moderately firm irregular whitish mass of approximately 5 cm in diameter, occupying the right orbit. Microscopically, a poorly differentiated neoplasm was observed. The immunohistochemical panel included cytokeratins, vimentin, epithelial membrane antigen, Factor VIII, CD34, Mart-1, Melan A, smooth muscle actin, desmin, chromogranin, neuron-specific enolase, S-100 protein, and MIB-1. The neoplasm was negative for all of them, with the exception of vimentin and S-100 protein. Transmission electron microscopy revealed abundant desmosomes. These findings support the diagnosis of orbital (retrobulbar) meningioma.

Differential reactivity for galectin-3 in Hürthle cell adenomas and carcinomas.

Hürthle cell carcinomas behave as the most aggressive variant of differentiated thyroid carcinoma of follicular origin, with frequent recurrences and higher morbidity. Its differential diagnosis with Hürthle cell adenoma remains a problem for the clinician and for the pathologist. The vertebrate lectins, galectin-1 and galectin-3 have been implicated in the regulation of cellular growth, differentiation, and malignant transformation in thyroid neoplasms. Galectin-3, a beta-galactoside binding protein, has been recently found to be highly expressed in papillary and follicular carcinomas. The current study was undertaken to investigate immunohistochemical reactivity for galectin-3 of thyroid specimen tissues with Hürthle cell adenomas (n = 14) and carcinomas (n = 17), follicular (n = 14) and papillary (n = 11) carcinomas, colloid goiter (n = 30), Hashimoto's thyroiditis (n = 11), follicular adenoma (n = 9), and normal thyroid tissues (n = 18). Follicular (78.5%) and papillary (82.0%) carcinomas were frequently reactive for galectin-3, more often when some H rthle cells were present. There was no galectin-3 immunostaining in any of the specimens from Hashimoto's thyroiditis, colloid goiters or normal thyroid samples, whereas only one case of follicular adenoma was found positive (11.1%). By contrast, galectin-3 immunostaining in Hürthle cell carcinomas was significantly higher (59%) than in H rthle cell adenomas (7.1), p < 0.05). These results suggest that galectin-3 may potentially serve as a marker in difficult differential diagnosis cases involving Hürthle cell adenomas and Hürthle cell carcinomas.

Immunocytochemistry applied to aspiration biopsy cytology. Diagnostic contribution in 100 cases of previously stained, routine specimens.

OBJECTIVE: To assess the contribution of immunocytochemistry (ICC) to aspiration biopsy cytology (ABC), in a diagnostic context, on routine, previously stained cytologic specimens. STUDY DESIGN: Among 5,221 consecutive cases of ABC, 5.3% were subjected to ICC in the clinical-morphologic context. One hundred of these cases, with a final clinical and histopathologic diagnosis, were studied to determine the contribution of this ancillary technique to the final cytologic diagnosis. All cases had histopathologic study and prospective ICC, performed on usual smears, alcohol fixed and previously stained by the Papanicolaou technique, and were subjected to an avidinbiotin-peroxidase complex method. RESULTS: ICC was contributory in 82% of cases. The contribution of ICC to ABC of lymphoid tissue, thyroid and related organs, soft tissue and miscellaneous cases was, respectively, 84% (39 cases), 88% (26), 72% (18) and 76% (17). ICC was noncontributory in 18 cases, due mainly to misleading interpretation (6%), uncharacteristic profile (5%) and inconclusive immunostain (7%). CONCLUSION: ICC could be successfully applied in routine ABC specimens since the usually investigated antigenic determinants are preserved, allowing previous morphologic study and screening of the smears. The principal contribution of ICC applied to lymph nodes, thyroid and soft tissue aspirates was, respectively, confirmation of metastatic neoplasms, differential of follicular versus C-cell proliferation and assessment of mesenchymal lineages.

Utilizaçäo de classificaçäo de Dorfman-Warnke (modificada por Burke) em patologia veterinária na avaliaçäo da linfadenite induzida por parvovírus canino em cobaias (Cavia porcellus) / Use of the Dorfman-Warnke classification (modified by Burke) in veterinary pathology in the evaluation of the lymphadenitis induced through canine parvovirus in guinea-pigs (Cavia porcellus)

Em patologia humana, a análise e interpretaçäo das linfadenopatias reacionais baseia-se na caracterizaçäo morfológica das várias regiöes do linfonodo. Em patologia veterinária náo há essa padronizaçäo. No presente estudo, utilizamos as bases da classificaçäo de Dorfmari-Wamke (modificada por Burke), utilizada na área médica humana para avaliarmos uma linfadenite viral experimental em cobaias. Parvovírus canino foi inoculado em coxim plantar de cobaias e a resposta dos linfonodos poplíteos avaliada. No fim de cada período experimental, linfonodos foram excisados, pesados e processados histologicamente em cortes corados pelos métodos de Giemsa, Mallory, Gordon & Sweets e Hematoxilina-Eosina e por meio de imunoistoquímica com anticorpos pan-T e pan-B. Foi observado aumento de peso significante (p

Adenocarcinoma in females detected in serous effusions. Cytomorphologic aspects and immunocytochemical reactivity to cytokeratins 7 and 20.

OBJECTIVE: To investigate the usefulness of assessing the immunoreactivity of cytokeratins 7 (CK7) and 20 (CK20) as well as several cytomorphologic parameters in effusions with metastatic adenocarcinomas in the search for the primary site of the tumor. STUDY DESIGN: From the files of the Pathology Department, A. C. Camargo Hospital, we studied cytologic smears from 73 metastatic adenocarcinomas originally from the breast, 63 from the ovary, 40 from the lung and 32 from the stomach, looking for morphologic parameters that could have discriminant potential in suggesting the primary site in a routine situation, including intranuclear inclusions, prominent nucleoli, mitosis, signet-ring cells, psammoma bodies, nuclear crease, binucleation and multinucleation, papillary features, acinar profile (including ball cells) and single cells. Immunoreactions were performed with monoclonal antibodies to CK7 (OV-TL 12/30) and CK20 (Ks 20.8) and included morphologic analysis. Both analyses were studied in a blind fashion regarding the primary site of the tumors. RESULTS: Positivity ratios for breast, ovary, stomach and lung cases were 67.6%, 63.5%, 29.7% and 45.5%, respectively, for CK7 and 17.2%, 15.8%, 13.5% and 32.2%, respectively, for CK20. Discriminant analysis of morphologic and immunocytochemical parameters had an error rate of 42.9% in recognizing the primary site and a Wilk's lambda of .7290. CONCLUSION: The more efficient parameter with discriminant function was the papillary appearance showed by CK7, which should be used in further studies with a similar scope. The set of parameters used in this study were insufficient to discriminate the primary site of female adenocarcinomas in effusions with significant accuracy.

Cytomorphologic evidence of human papillomavirus infection in smears from the irradiated uterine cervix.

OBJECTIVE: To report the cytomorphologic evidence of human papillomavirus (HPV) infection in cervical smears from women treated with radiotherapy for carcinoma of the uterine cervix. STUDY DESIGN: From January 1986 to December 1993, 32 cervical cytologic smears (CCSs) from women who had received radiotherapy (Rtx) for squamous cell cervical carcinoma at A.C. Camargo Cancer Hospital were selected for study due to the presence of signs of HPV infection. Review of the files of these patients showed 22 additional samples, which we included in this study. The avidinbiotin-immunoperoxidase technique was performed on previously stained slides using polyclonal rabbit antibovine papillomavirus type 1 to confirm the HPV infection. RESULTS: Positive reactions were found in 18 cases (27 samples), mainly in cells with classic koilocytotic features, but also in epithelial cells that lacked cytopathic effects. Only one case, a biopsy from a verrucous lesion observed after Rtx, was found to be positive for HPV 6/11 DNA by in situ hybridization. CONCLUSION: Cytologic and immunohistochemical positivity for HPV, as well as the reaction with a HPV 6/11 DNA probe, strongly suggested that HPV infection was acquired or expressed after radiotherapy. Further studies are needed to assess the mechanisms responsible for such an association.

Lactoferrin in thyroid lesions: immunoreactivity in fine needle aspiration biopsy samples.

OBJECTIVE: Lactoferrin is an iron-binding protein that has been used for distinguishing normal from neoplastic conditions in many different tissues. In order to improve evaluation of thyroid lesions, we studied the lactoferrin immunoreaction in cytologic smears obtained by fine needle aspiration and in biopsy samples from primary neoplasms and from adenomatous goiter. STUDY DESIGN: A retrospective study on fine needle aspiration cytology samples and corresponding available biopsies from thyroid lesions in patients examined at São Paulo County Hospital between 1982 and 1992, performed in order to evaluate lactoferrin immunoreactivity in morphologically well characterized samples from neoplastic and nonneoplastic lesions. Immunoperoxidase procedures were performed using monospecific polyclonal rabbit antihuman lactoferrin as a primary antibody and biotinylated goat antirabbit IgG as a secondary antibody. Amplification was performed with the avidin-biotin-peroxidase complex, and the color sign of the positive reactions was developed using a diaminobenzidine solution. RESULTS: Lactoferrin was not detected in cytologic smears from goiters, whereas only one biopsy was slightly positive (1/21, or 4.76%). One smear from adenoma showed low positive staining (1/19, or 5.26%), which was present in 4 of 13 biopsies (30.77%) from adenoma. Papillary carcinomas were positive in 19 of 33 smears (57.58%) and in 100% of biopsies, whereas 31.25% (5/16) of follicular carcinoma smears were positive for lactoferrin, detected in all the biopsy samples. CONCLUSION: Lactoferrin immunoreactivity was strongly associated with neoplastic proliferation and may be used as a useful auxiliary marker to distinguish malignant from benign thyroid lesions in cytologic smears and biopsy samples.

Proliferating cell nuclear antigen immunoreaction in adrenal tumors.

AIMS AND BACKGROUND: We studied, retrospectively, 33 cases of adrenal tumors of children at the Pediatric Endocrinology Unit, Children's Institute, São Paulo State University Medical School, from 1975 to 1993. All patients had at least 2 years of follow-up with a few exceptions. METHODS: Clinical follow-up data were correlated with histopathologic review, laboratory data and cell kinetic evaluation (based on detection of proliferating cell nuclear antigens). RESULTS: With one exception, all the patients had presented signs of androgen production and had high levels of dehydro-epiandrosterone-sulfate. Tumor weight evaluation represented a good parameter of neoplasm evolution: of 19 cases weighing less than 250 g, 17 had no evidence of disease after surgery, and 2 had an unfavorable prognosis. Of 14 cases weighing more than 250 g, only 1 had no evidence of disease and 13 had an unfavorable evolution. CONCLUSIONS: Proliferating cell nuclear antigen (PCNA) was not helpful to evaluate adrenal neoplasm evolution: our study did not show any correlation between PCNA score and prognosis.

Frequency of epithelial giant cells in smears with Papillomavirus.

We re-screened cytological smears from patients who presented Human Papillomavirus (HPV) infection detected morphologically in order to verify the frequency of associated giant epithelial cells, as recently mentioned in the literature. Our results demonstrated that 14 (13.7%) of 102 cases showed the giant epithelial cells, associated or not with macronmucleosis, bi or multinucleation. Epithelial giant cells showed a poor reaction to the avidin-biotin-peroxidase to the BPV-1 antigen. We conclude that epithelial giant cell is not a frequent cytologic feature in HPV, and the avidin-biotin-peroxidase study did not detect a marked expression of HPV late antigen.

Immunohistochemistry of medullary thyroid carcinoma and C-cell hyperplasia by an affinity-purified anti-human calcitonin antiserum.

BACKGROUND: The diagnosis of medullary thyroid carcinoma (MTC) depends on the calcitonin immunohistochemistry. Familial MTC is associated with C-cell hyperplasia (CCH), whereas sporadic MTC is not. A specific and sensitive calcitonin immunohistochemistry is necessary for the diagnosis of MTC and CCH. METHODS: An affinity-purified anti-calcitonin antiserum (APxCT) was used for immunohistochemistry of the thyroids of 15 patients with MTC. The thyroids of five patients with familial MTC were studied in detail, with each gland sectioned in 48 areas. RESULTS: Between three and ten independent MTC were found in each thyroid, and CCH was found in all five patients (24.2%, varying from 8.4-56.3% of the 48 areas from each thyroid). MTC and CCH were localized mainly in the middle third and in the central axis of the thyroid lobes. They often were found together in the same area (in a total of 21 areas for the five thyroids sectioned in 48 areas) but ten areas with MTC did not have CCH, and 37 areas with CCH did not have MTC. In ten thyroids partially studied, CCH was indicated in three patients thought to have sporadic MTC. In two thyroids, with follicular and papillary carcinoma, a higher density of C-cells was found around the tumors, but disease was not characterized as CCH. CONCLUSIONS: APxCT antiserum increased the immunohistochemical specificity and sensitivity. The distinction of the familial from the sporadic MTC requires a careful and extensive search of CCH. C-cells in high density may be found around follicular cell carcinomas, being a potential source of diagnostic error.

[The importance of fixation in immunohistochemistry: distribution of vimentin and cytokeratins in samples fixed in alcohol and formol]. / A importância da fixação em imuno-histoquímica: a distribuição de vimentina e citoqueratinas em amostras fixadas em alcool e formol.

The fixation in ethanol or formalin for trypsin digestion in immunohistochemical detection of cytokeratins and vimentin was assessed in a case of ovarian cystadenofibrocarcinoma. Superior reactivity for both markers was achieved in ethanol-fixed sections, even in samples stocked up to 60 days. Cytokeratin reaction in formalin-fixed sections was better when trypsin was used. However, this digestion was deleterious to vimentin detection. These data are presented to alert surgeons and oncologists on the relevance of fixation of specimens suspicious for neoplasia, since different epitopes may require different fixatives and the inadequate choice in the operative room may impart difficulties when immunohistochemistry is necessary.

Leptospiral antigens (L. interrogans serogroup ictero-haemorrhagiae) in the kidney of experimentally infected guinea pigs and their relation to the pathogenesis of the renal injury.

The search for leptospiral antigens (L. interrogans serogroup icterohaemorrhagiae) was carried out in 24 guinea pigs experimentally inoculated with 1 ml of culture containing 10(7)-10(8) leprospires and sequentially sacrificed from the first until the 6th day of infection. Semiquantitative analysis of histopathological variables comprising kidney interstitium, tubules and glomeruli was done in 1 micron sections of tissue embedded in glycolmetacrylate. Leptospiral antigen (LAg) and its glycolipoprotein (GLP) expression were detected through PAP in paraffin embedded tissue. The mild interstitial involvement of the kidney, manifested chiefly by oedema and focal interstitial nephritis seen at the 4th day, progressed to tubular damage at the 6th day, characterized by either swelling or cytoplasmic acidophilia of epithelial cells with loss of cell cohesion and sloughing of cells into the tubular lumina. Brush border alterations and mitochondrial changes were observed. Endothelial cell injury was noted in the interstitial vessels. LAg expression was parallel to the kidney changes: small deposits of elongated forms of LAg were detected at the 4th day either within the vascular lumen or free in the interstitium. A rise in the antigen expression was observed at the 5th day when it was seen either around tubules or in their walls. LAg was detected inside the tubular lumina at the 6th day of infection when granular LAg and GLP were abundant. This sequence reproduces the pathway of leptospires in the kidney and the crescent amounts of antigens detected toward the end of the experiment, with antigen concentration in cases of major tissue damage suggesting a direct action of the microorganisms and/or their products in the pathogesis of the lesions.

Herpes simplex virus in postradiation cervical smears. A morphologic and immunocytochemical study.

From January 1987 to August 1988, cytomorphologic criteria of both herpes simplex virus (HSV) and radiation effects were observed in Papanicolaou smears from 3 of 1,340 patients who had received radiotherapy for squamous cell carcinoma of the cervix. Avidin-biotin immunoperoxidase staining, using a rabbit IgG polyclonal HSV antibody, confirmed the presence of HSV antigen in those three postradiation smears. Both multinucleated molded cells and epithelial cells that lacked cytopathic effects were positive for HSV. Three other postradiation smears from these cases were similarly positive for HSV antigen; the one preradiation smear was negative. In situ hybridization and immunoperoxidase studies on sections from the preradiation biopsies were negative: severely altered neoplastic cells showed no reactivity. The absence of HSV markers in the preradiation specimens suggests that the HSV infections were secondary to the radiotherapy; further studies are needed to prove this association and to assess the possible mechanisms. These cases clearly indicate that the overlapping features of radiation and viral effects (such as multinucleation) may be present simultaneously.