ABSTRACT
A 16-year old girl with Gorham-Stout disease is presented. She had progressive replacement of the bones of her left arm and shoulder girdle by fibroadipose tissue and numerous proliferated, non-neoplastic, lymphatic channels. The clinico-pathologic features of this condition are discussed, as are its possible complications and available therapeutic modalities.
ABSTRACT
What is known and objective Polymyxins were widely used until the 1960s; however, they fell into disfavour owing to their toxicity. The subsequent growth of infections caused by multidrug-resistant Gram-negative bacteria has led to renewed use of this class of antimicrobials in clinical practice. Acquired skin hyperpigmentation (SH) following intravenous polymyxin B treatment has been previously reported, but little is known about its pathogenesis, clinical course and treatment. To improve understanding of these issues, we conducted a prospective study of adult patients receiving intravenous polymyxin B treatment. Methods Patients receiving intravenous polymyxin B treatment were followed throughout the course of treatment. Clinical, dermatoscopic, histologic and immunohistochemical skin properties of patients who presented with SH were studied. Results and discussion Skin hyperpigmentation was noted in 8% of patients (n=20/249); however, clinical, dermatoscopic, histologic and immunohistochemical examinations were performed only in three patients for whom the consent of relatives was obtained. Histologic and immunohistochemical findings showed an abundant melanocyte-pigmented dendritic network. Langerhans cells' hyperplasia and dermal IL-6 overexpression were also found, presumably for an inflammatory process due to polymyxin B use. As polymyxin B causes the release of histamine, which is known for its melanogenic effect, it is possible that skin darkening is associated with this inflammatory mediator. What is new These clinical and dermatoscopic findings contribute to a better understanding of how the pigmentary reaction manifests following intravenous polymyxin B treatment. Conclusion We concluded that hyperpigmentation due to intravenous polymyxin B treatment is associated with an inflammatory process and subsequent melanocyte activation. Although the pigmentary disorder neither influences the outcome of the therapy nor warrants discontinuation of treatment, it nevertheless considerably affects the patient's quality of life.
Subject(s)
Anti-Bacterial Agents/adverse effects , Hyperpigmentation/chemically induced , Melanocytes/metabolism , Polymyxin B/adverse effects , Administration, Intravenous , Adult , Anti-Bacterial Agents/administration & dosage , Drug Resistance, Multiple, Bacterial , Female , Gram-Negative Bacterial Infections/drug therapy , Humans , Inflammation/chemically induced , Inflammation/pathology , Male , Middle Aged , Polymyxin B/administration & dosage , Prospective Studies , Quality of LifeABSTRACT
Paracoccidioidomycosis (PCM) is the most important systemic mycoses in Latin America. We describe a severe case of paracoccidioidomycosis in a 14-year-old boy, with a rapid disease progression. The fungal strain was isolated and inoculated into a T and/or B cell immunocompromised mice, which revealed a highly virulent strain. The case report presented herein emphasizes the importance of considering PCM in the differential diagnosis of patients with other infectious diseases in endemic areas and highlights a novel isolate.
Subject(s)
Paracoccidioides/isolation & purification , Paracoccidioidomycosis/diagnosis , Paracoccidioidomycosis/pathology , Adolescent , Animal Experimentation , Animals , Brazil , Histocytochemistry , Humans , Immunocompromised Host , Lymph Nodes/pathology , Male , Mice , Microscopy , Paracoccidioides/pathogenicity , Paracoccidioidomycosis/microbiology , Survival AnalysisABSTRACT
BACKGROUND: Psoriasis is a chronic inflammatory disease that affects the skin. CD4(+) CD28(null) cells are a subset of T lymphocytes associated with systemic inflammation and increased cardiovascular disease risk, and may be involved in the pathogenesis of psoriasis. OBJECTIVES: To study the features of circulating CD4(+) CD28(null) cells in patients with psoriasis, adjusted for the influence of known cardiovascular disease risk factors. METHODS: Forty-two patients with psoriasis and 42 controls entered the study. Peripheral blood mononuclear cells were analysed for the frequency of CD4(+) CD28(null) T lymphocytes and their expression of cytotoxic granules and homing receptors. Immunostaining for cutaneous cytotoxic granules was assessed in skin biopsies from 11 patients. RESULTS: There were no differences in the frequency of CD4(+) CD28(null) T cells between groups in all situations analysed. However, there was an increased number of cells expressing cytotoxic granules and a decreased number expressing CXCR3 in ex vivo samples of patients with psoriasis. A negative correlation was observed between the frequency of ex vivo CD4(+) CD28(null) cells and psoriasis severity. After clinical remission in nine patients, ex vivo CD4(+) CD28(null) lymphocytes expressing cytotoxic granules decreased. Perforin-, granzyme B- and granulysin-containing cells were found in skin lesions. Patients with psoriasis also had increased plasma levels of C-reactive protein. CONCLUSIONS: These data suggest that cytotoxic cells, such as CD4(+) CD28(null) lymphocytes, within an inflammatory environment may play a role in the pathogenesis of psoriasis.
Subject(s)
CD28 Antigens/metabolism , CD4-Positive T-Lymphocytes/immunology , Psoriasis/immunology , T-Lymphocytes/immunology , C-Reactive Protein/metabolism , Case-Control Studies , Female , Humans , Male , Middle Aged , Prospective Studies , Psoriasis/drug therapy , Receptors, CXCR3/metabolism , Remission InductionABSTRACT
In cutaneous lupus erythematosus (CLE), the pathogenetic role of cytotoxic granules has been demonstrated in the subacute and discoid subtypes, which show interface dermatitis, but little is known about tumid (T)CLE, which does not show this interface dermatitis, and evolves with minimal epidermal changes. We studied cytotoxic T lymphocytes and cytotoxic granules in discoid (n = 21), subacute (n = 17), and tumid (n = 21) CLE samples. Skin sections were immunohistochemically stained for CD8, CD56, perforin, granzyme A, granzyme B, and granulysin. Inflammatory cells containing the four subtypes of cytotoxic granules were found in all the three CLE forms; however, only the TCLE group showed a positive correlation between the density of CD8+ cells and each subtype of cytotoxic granule-positive cells. In addition, only the TCLE group showed synergy between the densities of cells containing cytotoxic granule subtypes. Cytotoxic granules are important in the pathomechanism of TCLE. They may perform functions other than apoptosis, including maintenance of inflammation and dermal mucinous deposits in TCLE.
Subject(s)
Lupus Erythematosus, Cutaneous/immunology , T-Lymphocytes, Cytotoxic/immunology , Antigens, Differentiation, T-Lymphocyte/metabolism , CD56 Antigen/analysis , CD8-Positive T-Lymphocytes/immunology , Cell Count , Granzymes/metabolism , Humans , Immunohistochemistry , Lupus Erythematosus, Cutaneous/metabolism , Lupus Erythematosus, Cutaneous/pathology , Perforin/metabolism , Retrospective StudiesABSTRACT
BACKGROUND: Chronic telogen effluvium (CTE), a poorly understood condition, can be confused with or may be a prodrome to female pattern hair loss (FPHL). The pathogenesis of both is related to follicle cycle shortening and possibly to blood supply changes. AIM: To analyze a number of histomorphometric and immunohistochemical findings through vascular endothelial growth factor (VEGF), Ki-67, and CD31 immunostaining in scalp biopsies of 20 patients with CTE, 17 patients with mild FPHL and 9 controls. METHODS: Ki-67 index and VEGF optical density were analyzed at the follicular outer sheath using ImageJ software. CD31 microvessel density was assessed by a Chalkley grid. RESULTS: Significant follicle miniaturization and higher density of nonanagen follicles were found in FPHL, compared with patients with CTE and controls. Ki-67+ index correlated positively with FPHL histological features. The FPHL group showed the highest VEGF optical density, followed by the CTE and control groups. No differences were found in CD31 microvessel density between the three groups. CONCLUSIONS: Histomorphometric results establish CTE as a distinct disorder, separate from FPHL from its outset. Its pathogenic mechanisms are also distinct. These findings support the proposed mechanism of 'immediate telogen release' for CTE, leading to cycle synchronization. For FPHL, accelerated anagen follicular mitotic rates and, thus, higher Ki-67 and VEGF values, would leave less time for differentiation, resulting in hair miniaturization.
Subject(s)
Alopecia , Hair Follicle , Adolescent , Adult , Aged , Alopecia/etiology , Alopecia/metabolism , Alopecia/pathology , Case-Control Studies , Chronic Disease , Female , Hair Follicle/blood supply , Hair Follicle/pathology , Humans , Immunohistochemistry , Ki-67 Antigen/metabolism , Middle Aged , Platelet Endothelial Cell Adhesion Molecule-1/metabolism , Prospective Studies , Scalp/metabolism , Vascular Endothelial Growth Factor A/metabolism , Young AdultABSTRACT
The objective of this study was to test the relationship between histological changes in minor salivary glands (MSG) and chronic GVHD (cGVHD) severity and OS of hematopoietic SCT (HSCT) patients, and to discriminate the participation of events preceding HSCT that damage MSG, from those linked to cGVHD. The MSG of 57 HSCT patients who were divided into two groups-oral cGVHD (36 cases) and non-cGVHD (21 cases)-were compared with the MSG of a control group of 19 non-HSCT individuals. cGVHD changes were assessed according to National Institutes of Health (NIH) consensus and the systems of Horn et al. Acinar areas and mononuclear cell subsets were set through morphometry. Horn's 'periductal lymphocytic infiltrate' correlated with an extensive form of cGVHD and NIH 'periductal lymphocytes with exocytosis into duct' correlated with global survival. Measurements of the acinar area differed between the three groups, being the lowest in cGVHD patients, but also reduced in non-cGVHD patients. Significant differences among CD45, CD45RO, CD4 and CD8 immunomarked cells/mm(2) were found by comparing the two groups of HSCT patients. In brief, periductal lymphocytic infiltrate and exocytosis implies inflammatory activity and, consequently, might reflect the cGVHD status and influence survival. Acini loss in non-cGVHD patients may be due to pre-transplant events, but massive lymphocyte infiltrate is part of the cGVHD process.
Subject(s)
Graft vs Host Disease/pathology , Hematopoietic Stem Cell Transplantation/methods , Salivary Glands, Minor/pathology , Transplantation, Autologous/adverse effects , Adolescent , Adult , Child , Female , Graft vs Host Disease/immunology , Hematopoietic Stem Cell Transplantation/adverse effects , Humans , Immunohistochemistry , Male , Middle Aged , Retrospective Studies , Salivary Glands, Minor/immunology , Transplantation Conditioning/adverse effects , Transplantation Conditioning/methods , Young AdultABSTRACT
Antimalarial drugs, like chloroquine, may produce hyperpigmentation of the oral mucosa, affecting most commonly the palate. Its pathogenesis is not clear; an increased production of melanin is currently believed to be the cause of this oral manifestation. The purpose of this study was to report a case of atypical oral mucosal hyperpigmentation secondary to antimalarial therapy. A 66-year-old, dark skinned woman was evaluated for oral pigmentation. The patient had a history of chloroquine therapy, and presented a diffuse blue-gray pigmentation in the hard palate and, mainly, in the lower lip. Diagnostic hypothesis were of physiologic pigmentation, drug-induced pigmentation, pigmentation associated with systemic diseases, smoker's melanosis and post-inflammatory pigmentation. Incisional biopsy was conducted and histopathological examination revealed lichenoid dermatitis and pigment incontinence. Fontana-Masson staining was positive for melanin, but Perl's iron staining was negative. The histopathological diagnosis was consistent with melanin incontinence related to drug-induced lichenoid reaction secondary to chloroquine therapy. Adequate correlation of clinical and microscopic aspects was essential for the definitive diagnosis, especially in atypical cases. This diagnosis is of great relevance for the patient, since the oral manifestation might be an early sign of ocular complications due to antimalarial therapy. Therefore, the identification of these oral manifestations indicates regular evaluations by an ophtalmologist, preventing greater complications of antimalarial therapy for the patient.
Subject(s)
Antimalarials/adverse effects , Chloroquine/adverse effects , Lichenoid Eruptions/chemically induced , Lip Diseases/chemically induced , Aged , Female , Humans , Lichenoid Eruptions/pathology , Lip Diseases/pathologyABSTRACT
The purpose of this study was to investigate clinical and histomorphometric features of cat skin under long-term solar exposure. Ear skin of 34 Domestic Shorthair cats that were chronically exposed to sun was classified as follows: group 0, normal (n = 13); group 1, initial stage of photodamage (PD) (n = 10); group 2, advanced stage of PD (n = 11). Histologic sections were examined independently by 2 pathologists, and epidermal thickness, adnexal unit area, and dermal cellularity were assessed by morphometry. A positive correlation was obtained between age, degree of edema and sclerosis in the upper dermis, telangiectases, squamatization of basal keratinocytes, and epidermis thickness and the degree of PD. The area occupied by adnexal structures in the dermis diminished with increased PD. Dermal sclerosis and edema best separated the 3 groups. The results indicated a high level of skin hypersensitivity to sun rays in cats. The findings may be useful for clinical testing and in general veterinary pathology and dermatology.
Subject(s)
Keratosis/veterinary , Skin Diseases/veterinary , Skin/pathology , Skin/radiation effects , Sunlight/adverse effects , Animals , Biopsy , Cats , Ear/pathology , Ear/radiation effects , Female , Keratosis/etiology , Keratosis/pathology , Male , Skin Diseases/etiology , Skin Diseases/pathologyABSTRACT
BACKGROUND: Mycosis fungoides (MF) is the most common skin lymphoid neoplasm. In initial stages, differential diagnosis of MF from other benign dermal lymphoid infiltrates (BDLI) may be impossible on morphological basis alone. In previous studies, only deletion of CD7 in MF proved to be of diagnostic help, but not the ratio between immunoexpression of CD4 and CD8. METHODS: 30 cases of MF and 11 cases of BDLI were analysed, in order to compare morphometric parameters, which could be of diagnostic aid. As CD7 is frequently deleted in MF, immunohistochemical detection of T-cells was made using an antibody to CD3. Images of 100 CD3-positive cells per case in both groups were captured and analysed using a simple computer program for nuclear perimeter, area, diameter and nuclear contour index. RESULTS: All parameters showed statistically significant higher values for MF. Area was the variable with the strongest discriminating power between the two groups of patients. Thus even if morphological evaluation is not accurate to distinguish benign versus malignant dermal lymphoid infiltrates, due to the variability of size and shape of these cells, a more sensitive method promptly shows this difference. CONCLUSION: Results suggest that morphometry of CD3-positive lymphoid cells may add valuable information in the differential diagnosis of MF and benign dermatoses.
Subject(s)
Biomarkers, Tumor/metabolism , CD3 Complex/metabolism , Mycosis Fungoides/diagnosis , Skin Neoplasms/diagnosis , Antigens, Neoplasm/metabolism , Cell Nucleus/pathology , Diagnosis, Differential , Humans , Mycosis Fungoides/ultrastructure , Retrospective Studies , Sensitivity and Specificity , Skin Diseases/diagnosis , Skin Neoplasms/ultrastructureSubject(s)
HLA Antigens/genetics , Haplotypes , Psoriasis/genetics , Adolescent , Alleles , Brazil , Child , Female , Humans , MaleABSTRACT
Recently, a controlled double-blind study in patients with photo-aged facial skin demonstrated the beneficial role of oral intake of silanol for skin, hair and nails. The aim of our pilot study was to investigate histologic alterations in human skin after injection of silanol. Seven healthy female caucasian volunteers with a moderate degree of photoaged skin received ten sessions of weekly injections of 0.1% salicylate silanol in the left ventral lateral forearm. The histologic features of punch biopsies of the treated area and the nontreated contralateral arm were compared and the collagen and elastic fibers quantified. Texture analysis was performed on digitalized microscopic images by analyzing the Sarkar fractal dimension or amplitudes (inertia values) after Fast Fourier transformation. The treated area revealed a statistically significant increase of the density of both collagen and elastic fibers. Texture analysis showed more compact and homogeneously distributed collagen fibers after silicon injection. Our results suggest that the application of silicon may stimulate the production of collagen and elastic fibers leading to remodeling of the dermal fiber architecture, which may explain the improvement of the skin surface observed in clinical studies.
Subject(s)
Dermis/drug effects , Dermis/pathology , Salicylates/pharmacology , Skin Aging/drug effects , Adult , Biopsy , Collagen/drug effects , Collagen/metabolism , Dermis/metabolism , Dose-Response Relationship, Drug , Elastic Tissue/drug effects , Elastic Tissue/metabolism , Female , Humans , Middle Aged , Pilot Projects , Skin Physiological PhenomenaABSTRACT
Pyoderma gangrenosum (PG) is a neutrophilic dermatosis of unknown etiology characterized by typical skin ulcers. It may be related to systemic disorders but its association with solid tumors is very unusual. In this setting, we describe a patient in whom PG was the first and isolated manifestation of advanced gastric adenocarcinoma.
Subject(s)
Adenocarcinoma/complications , Adenocarcinoma/diagnosis , Pyoderma Gangrenosum/complications , Pyoderma Gangrenosum/diagnosis , Stomach Neoplasms/complications , Stomach Neoplasms/diagnosis , Adult , Diagnosis, Differential , Fatal Outcome , Gastroscopy , Humans , MaleSubject(s)
Aldehyde Oxidoreductases/genetics , Mutation , RNA Splice Sites/genetics , Sjogren-Larsson Syndrome/genetics , Adolescent , Adult , Base Sequence , Child , Child, Preschool , Female , Genetic Testing/methods , Humans , Male , Sjogren-Larsson Syndrome/diagnosis , Sjogren-Larsson Syndrome/pathologyABSTRACT
BACKGROUND: The established pathologic criteria for minor salivary gland (MSG) involvement in chronic graft-vs.-host disease (cGVHD) could play a role in monitoring response to therapy. METHODS: We evaluated MSG sequential biopsies during cGVHD therapy in 14 allogeneic bone marrow transplantation (BMT) patients. Nine patients that did not develop GVHD after BMT entered the control group. Biopsies were examined using hematoxylin-eosin, Periodic acid-Schiff (PAS) and leukocyte common antigen staining. RESULTS: A significant loss of PAS+ acinar volume was observed at the diagnosis of cGVHD as much as at the end of treatment when compared with the control group. In the second evaluation, the inflammatory infiltrate was still greater than control group. CONCLUSIONS: The results suggest that persistent xerostomia after cGVHD treatment is because of maintenance of lymphocytic infiltrate and consequent absence of MSG secretory unit recovery. This data may be useful to provide improved insight into the histopathology of this organ involvement.
Subject(s)
Graft vs Host Disease/complications , Graft vs Host Disease/pathology , Salivary Glands, Minor/pathology , Xerostomia/etiology , Adolescent , Adult , Anti-Inflammatory Agents/therapeutic use , Biopsy , Bone Marrow Transplantation/adverse effects , Case-Control Studies , Chronic Disease , Cyclosporine/therapeutic use , Female , Graft vs Host Disease/drug therapy , Graft vs Host Disease/etiology , Humans , Immunosuppressive Agents/therapeutic use , Leukemia, Myeloid/therapy , Male , Middle Aged , Periodic Acid-Schiff Reaction , Prednisone/therapeutic useABSTRACT
BACKGROUND: Graft-vs.-host disease (GVHD) is the major cause of morbidity and mortality in patients undergoing allogeneic Bone Marrow Transplantation (BMT). The aim of our study was to identify the most relevant histological features for diagnosis of chronic Graft-vs.-Host Disease (cGVHD) in oral mucosa and minor salivary glands of 25 patients, as well as to evaluate the immunophenotype of the inflammatory cells. METHODS: Sixteen patients that were submitted to allogeneic BMT but did not present cGVHD were selected as a control group. The sections were studied on H & E and CD68, CD45, CD4, CD8, CD20 staining. RESULTS: The most frequent histologic findings in oral mucosa at the day of diagnosis of cGVHD were: hydropic degeneration of the basal layer of the epithelium, apoptotic bodies, lymphocytic infiltration, and focal or total cleavage between the epithelial and connective tissue. In the labial salivary glands (LSG), lymphocytic infiltration, acinar loss and fibrosis were the main alterations. Cytotoxic CD8-T cells and macrophages were predominant both in the epithelium and connective tissue, as well as in minor salivary glands. CONCLUSIONS: Histological features were useful in the diagnosis of oral cGVHD. It is suggested that CD8-T cells and macrophages play important role in the pathogenesis of the disease.
Subject(s)
Graft vs Host Disease/pathology , Mouth Diseases/pathology , Mouth Mucosa/pathology , Salivary Gland Diseases/pathology , Salivary Glands, Minor/pathology , Adolescent , Adult , Antigens, CD/analysis , Antigens, CD20/analysis , Antigens, Differentiation, Myelomonocytic/analysis , Apoptosis , CD4 Antigens/analysis , CD8 Antigens/analysis , CD8-Positive T-Lymphocytes/pathology , Chronic Disease , Connective Tissue/pathology , Epithelium/pathology , Female , Graft vs Host Disease/immunology , Humans , Leukocyte Common Antigens/analysis , Lymphocytes/pathology , Macrophages/pathology , Male , Middle Aged , Mouth Diseases/immunology , Mouth Mucosa/immunology , Retrospective Studies , Salivary Gland Diseases/immunology , Salivary Glands, Minor/immunologyABSTRACT
INTRODUCTION: 2-Chlorodeoxyadenosine (cladribine or 2-CdA) is a purine analogue that has been used successfully in hairy cell leukaemia (HCL). Moreover, it has been increasingly used to treat chronic lymphoproliferative syndromes and paediatric acute myeloid leukaemia. Cutaneous side-effects associated with this drug have seldom been described in cases of HCL. PATIENTS AND METHODS: We describe three patients with chronic lymphocytic leukaemia that presented generalized skin eruptions after treatment with 2-CdA. RESULTS: All patients had advanced disease, receiving 2-CdA as a second or third line chemotherapy. Skin lesions were severe and chemotherapy had to be discontinued. Histological examination of skin biopsies showed an eosinophil-rich infiltrate with flame figures, similar to what is observed in Wells' syndrome (eosinophilic cellulitis). Corticosteroids were effective to control the eruptions. CONCLUSIONS: Cutaneous adverse reactions associated with 2-CdA have seldom been observed in the treatment of HCL. However, as this purine analogue has been used in more advanced cases these may be more frequent and severe. The pathophysiology of these lesions is unclear, but it is probably related to drug-induced change in T-cell imbalance in severely immunosuppressed patients.
Subject(s)
Antineoplastic Agents/adverse effects , Cladribine/adverse effects , Drug Eruptions/diagnosis , Exanthema/diagnosis , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Aged , Antineoplastic Agents/administration & dosage , Cladribine/administration & dosage , Diagnosis, Differential , Drug Eruptions/etiology , Drug Eruptions/pathology , Exanthema/chemically induced , Exanthema/pathology , Female , Humans , Middle AgedABSTRACT
We describe a case of primary aspergillosis involving the tongue of a patient with acute myeloid leukemia. Intraoral aspergillosis is very rare and we found only 23 cases reported in the English literature. Clinically it was a 2-cm, ulcerated, grayish lesion on the dorsum of the tongue. Microscopically there was invasion of the epithelium, connective tissue and muscle of the tongue by fungal hyphae branching at 45 degrees angle. The large hyphae were easily seen by H & E stain, and were strongly positive for periodic acid-Schiff and Grocott methenamine. The patient was successfully treated with intravenous amphotericin B. Based on clinical, microscopic and culture data, the diagnosis of primary aspergillosis of the tongue was established. Invasive oral aspergillosis is a potentially lethal disease and it should be considered in immunosuppressed patients.
Subject(s)
Aspergillosis/etiology , Aspergillus flavus , Leukemia, Myeloid/complications , Tongue Diseases/microbiology , Acute Disease , Adolescent , Amphotericin B/therapeutic use , Antifungal Agents/therapeutic use , Aspergillosis/drug therapy , Aspergillosis/pathology , Aspergillus flavus/isolation & purification , Humans , Hyphae , Immunocompromised Host , Male , Tongue Diseases/drug therapy , Tongue Diseases/pathologyABSTRACT
During 1985-1995, illnesses clinically and epidemiologically compatible with Brazilian spotted fever were identified in 17 patients in the county of Pedreira, in the state of São Paulo, Brazil. Spotted-fever group rickettsial infection was confirmed by serology and/or immunostaining of tissues in 10 of these patients. Immunostaining confirmed infection in a 37-year-old pregnant patient, although rickettsial antigens were not demonstrable in the tissues of the fetus. A serosurvey was conducted in four localities in the county to determine the prevalence of subclinical or asymptomatic infections with spotted fever group rickettsiae. Five hundred and twenty-five blood samples were tested by an indirect immunofluorescence assay for antibodies reactive with Rickettsia rickettsii. Twenty-two (4.2%) of these samples demonstrated titers > or = 1:64. The results indicate that Brazilian spotted fever is endemic within this region of Brazil.