Beyond diagnosis: exploring the significance of IgG4+ plasma cell count through immunostaining in IgG4-related disease.

OBJECTIVES: To evaluate whether the grade of IgG4+ plasma cell infiltration in biopsies is associated with clinical or serologic outcomes in IgG4-RD. METHODS: We included 57 patients with biopsy proven IgG4-RD according to the Comprehensive Diagnostic Criteria and/or the 2019 ACR/EULAR Classification Criteria. We collected histological, clinical (disease duration, phenotype, remission and relapses) and serological variables. RESULTS: 29 (50.9%) patients were men, mean age 49.9 years, with a median disease duration of 22 months. The distribution among clinical phenotypes were 14% pancreato-hepato-biliary, 12.3% retroperitoneal/aortic, 29.8% head and neck-limited, 29.8% Mikulicz/systemic and 14% undefined. Thirty-nine patients had a proliferative and 18 a fibrotic phenotype. Most biopsies were from lacrimal gland, lymph node, pancreas, orbit, kidney, retroperitoneum and thyroid gland. Thirty-nine (68.4%) patients had <100 IgG4+ plasma cells/HPF and 18 (31.6%) ≥100 IgG4+ plasma cells/HPF. Patients with ≥100 IgG4+ plasma cells/HPF were more likely to belong to the pancreato-hepato-biliary and the proliferative phenotypes, had fewer relapses and a higher remission rate. On multivariate analysis, the OR for remission at last follow-up was 6.7, 95% CI 1.1-4.42, p=0.03. The log-rank test showed a difference in relapse-free survival between the two groups (HR 2.6, 95% CI 1.2-5.6, p=0.01). According to the ROC analysis, patients with more than 61 IgG4+ plasma cells were less likely to relapse. CONCLUSIONS: A count of ≥100 IgG4+ plasma cells/HPF may identify patients with a proliferative phenotype, fewer relapses and a higher remission rate.

Is Iron Overload Associated with Worse Outcomes in Patients with Chronic Liver Disease Undergoing Liver Transplantation?

ABSTRACT Background: Iron overload is frequent in patients with chronic liver disease, associated with shorter survival after liver transplantation in patients with hereditary hemochromatosis. Its effect on patients without hereditary hemochromatosis is unclear. The aim of the study was to study the clinical impact of iron overload in patients who underwent liver transplantation at an academic tertiary referral center. Methods: We performed a retrospective cohort study including all patients without hereditary hemochromatosis who underwent liver transplantation from 2015 to 2017 at an academic tertiary referral center in Mexico City. Explant liver biopsies were reprocessed to obtain the histochemical hepatic iron index, considering a score ≥ 0.15 as iron overload. Baseline characteristics were compared between patients with and without iron overload. Survival was estimated using the Kaplan-Meier method, compared with the log-rank test and the Cox proportional hazards model. Results: Of 105 patients included, 45% had iron overload. Viral and metabolic etiologies, alcohol consumption, and obesity were more frequent in patients with iron overload than in those without iron overload (43% vs. 21%, 32% vs. 22%, p = 0.011; 34% vs. 9%, p = 0.001; and 32% vs. 12%, p = 0.013, respectively). Eight patients died within 90 days after liver transplantation (one with iron overload). Complication rate was higher in patients with iron overload versus those without iron overload (223 vs. 93 events/100 person-months; median time to any complication of 2 vs. 3 days, p = 0.043), without differences in complication type. Fatality rate was lower in patients with iron overload versus those without iron overload (0.7 vs. 4.5 deaths/100 person-months, p = 0.055). Conclusion: Detecting iron overload might identify patients at risk of early complications after liver transplantation. Further studies are required to understand the role of iron overload in survival.

Is iron overload associated with worse outcomes in patients with chronic liver disease undergoing liver transplantation?

Background: Iron overload is frequent in patients with chronic liver disease, associated with shorter survival after liver transplantation in patients with hereditary hemochromatosis. Its effect on patients without hereditary hemochromatosis is unclear. The aim of the study was to study the clinical impact of iron overload in patients who underwent liver transplantation at an academic tertiary referral center. Methods: We performed a retrospective cohort study including all patients without hereditary hemochromatosis who underwent liver transplantation from 2015 to 2017 at an academic tertiary referral center in Mexico City. Explant liver biopsies were reprocessed to obtain the histochemical hepatic iron index, considering a score ≥ 0.15 as iron overload. Baseline characteristics were compared between patients with and without iron overload. Survival was estimated using the Kaplan-Meier method, compared with the log-rank test and the Cox proportional hazards model. Results: Of 105 patients included, 45% had iron overload. Viral and metabolic etiologies, alcohol consumption, and obesity were more frequent in patients with iron overload than in those without iron overload (43% vs. 21%, 32% vs. 22%, p = 0.011; 34% vs. 9%, p = 0.001; and 32% vs. 12%, p = 0.013, respectively). Eight patients died within 90 days after liver transplantation (one with iron overload). Complication rate was higher in patients with iron overload versus those without iron overload (223 vs. 93 events/100 personmonths; median time to any complication of 2 vs. 3 days, p = 0.043), without differences in complication type. Fatality rate was lower in patients with iron overload versus those without iron overload (0.7 vs. 4.5 deaths/100 person-months, p = 0.055). Conclusion: Detecting iron overload might identify patients at risk of early complications after liver transplantation. Further studies are required to understand the role of iron overload in survival.

Performance of the 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4-Related Disease in a Latin American Cohort.

BACKGROUND/OBJECTIVE: The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria (2019 AECC) for IgG4-related disease (IgG4-RD) is considered a significant advancement in the study of this condition. Most studies evaluating their performance have focused on White and Asian patients, leaving a knowledge gap regarding Latin American populations. Therefore, this study aimed to assess the performance of the 2019 AECC for IgG4-RD in a cohort of Latin American patients. METHODS: A multicenter medical records review study was conducted, involving centers from Argentina, Chile, Mexico, Peru, and Uruguay. Data on IgG4-RD patients and mimicker conditions were collected through a standardized online form. The criterion standard for diagnosing IgG4-RD was based on the fulfillment of the Comprehensive Diagnostic Criteria for IgG4-RD and/or the Consensus Statement on Pathology. The 2019 AECC was retrospectively applied. RESULTS: We included 300 patients, with 180 (60%) having IgG4-RD and 120 (40%) having mimicker conditions. The 2019 AECC had a sensitivity of 66.7% and a specificity of 100%. Sensitivity increased to 73.3% when disease-specific autoantibody items were removed, without affecting specificity. The true-positive cases had more involved organs, a higher availability of biopsy results, and were more likely to belong to the Mikulicz/systemic and proliferative phenotypes. CONCLUSIONS: The use of the 2019 AECC for IgG4-RD in a Latin American population confirms its high specificity in excluding those without the disease. The presence of concomitant autoimmune diseases and clinically nonsignificant disease-specific autoantibodies excludes a significant number of patients from fulfilling the criteria.

The Role of Postmastectomy Radiotherapy in Locally Advanced Breast Cancer After Pathological Complete Response to Neoadjuvant Chemotherapy.

The Case A previously healthy woman, aged 32 years, presented to the oncology clinic with a 6-month history of left-breast tumor, mastalgia, and swollen axillary nodes. Physical examination was relevant for a 6-cm palpable mass in the upper outer quadrant of the left breast and an ipsilateral 2-cm, nonfixed axillary lymph node. Mammography showed a 1-cm mass in the upper outer quadrant, a 5.2-cm mass in the lower outer quadrant, and enlarged pathologic lymph nodes (BI-RADS category 5 disease). Breast ultrasound revealed 3 axillary lymph nodes with cortical thickening and loss of normal morphology (the largest with a 2.6-cm length in the long axis) (Figure 1A-B). The breast´s core biopsy revealed a grade 3 apocrine invasive carcinoma with lymphovascular invasion; immunohistochemistry testing showed HER2-negative, hormone receptor-negative disease (estrogen receptor, 0%; progesterone receptor, 0%; HER2-negative, Ki67, 50%) (Figure 2A-B). A fine-needle aspiration biopsy of the axillary lymph nodes showed invasive breast carcinoma as well. Bone scintigraphy and a chest/abdomen CT scan ruled out metastatic disease. Upon initial diagnosis, clinical stage was deemed as cT3N1M0 (American Joint Committee on Cancer 8th edition: anatomic stage IIIA, clinical prognostic stage IIIC). After a multidisciplinary tumor board discussion, the patient underwent neoadjuvant chemotherapy with weekly paclitaxel, followed by 4 cycles of dose-dense doxorubicin plus cyclophosphamide. After completing neoadjuvant treatment, clinical examination was relevant for a residual 1-cm palpable left breast mass and no palpable axillary nodes. Mammography and breast ultrasound showed a 77% partial response in the primary tumors, and axillary nodes with normal morphology and size (Figure 1C-D). Due to multicentric tumor disease, breast-conserving surgery would not confer satisfactory cosmetic results on her, and a modified radical mastectomy with intraoperative sentinel lymph node biopsy (and second-stage breast reconstruction) was planned. However, during surgery, the surgeons failed to identify the mapped lymph node, and level I-III axillary lymph node dissection was performed. The pathology report described complete pathological response: Miller and Payne criteria grade 5 response with the absence of malignant cells within the mastectomy specimen and in 24 lymph nodes (Figure 2C-E). Pathological staging after neoadjuvant treatment concluded ypT0N0M0 disease. Subsequent treatment for this patient was discussed in another tumor board.

Características clínicas de los pacientes con fiebre manchada de las Montañas Rocosas, infección por dengue y chikungunya / Clinical features of patients with Rocky Mountain spotted fever, dengue and chikungunya infection

Resumen Introducción: La distinción clínica entre infecciones arbovirales y las provocadas por rickettsias es crucial para iniciar el tratamiento médico apropiado. Objetivo: Comparar las diferencias entre fiebre manchada de las Montañas Rocosas (FMMR) y otras enfermedades transmitidas por vector (dengue y chikungunya) con presentación clínica similar e identificar los datos que pudieran ayudar al diagnóstico rápido de esas enfermedades. Métodos: Se evaluaron datos sociodemográficos, clínicos y de laboratorio de 399 pacientes de cinco hospitales y clínicas en Sonora, México, entre 2004 y 2016, con el diagnóstico confirmado por laboratorio de FMMR, dengue o chikungunya. Resultados: El grupo con FMMR presentó la mayor letalidad (49/63 muertes, 77.8 %), seguido por el de chikungunya (3/161, 1.9 %) y el de dengue (3/161, 1.9 %). Las diferencias clínicas consistieron en la presencia de exantema, edema y prurito; además, se documentaron diferencias en múltiples biomarcadores como plaquetas, hemoglobina, bilirrubina indirecta y niveles de sodio sérico. Conclusión: El exantema en palmas y plantas, edema y ausencia de prurito, aunados a niveles altos de bilirrubina directa y trombocitopenia severa pudieran ser indicadores útiles para diferenciar a pacientes con FMMR en etapas avanzadas de aquellos con dengue y chikungunya.

Abstract Introduction: Clinical distinction between arbovirus infections and those caused by rickettsia is crucial to initiate appropriate medical treatment. Objective: To compare the differences between Rocky Mountain spotted fever (RMSF) and other vector-borne diseases (dengue and chikungunya) with similar clinical presentation, and to identify data that could aid rapid diagnosis of these diseases. Methods: Sociodemographic, clinical and laboratory data of 399 patients from five hospitals and clinics of Sonora, Mexico, with laboratory-confirmed diagnosis of RMSF, dengue, or chikungunya between 2004 and 2016 were evaluated. Results: The RMSF group had the highest lethality (49/63 deaths, 77.8 %), followed by the chikungunya group (3/161, 1.9 %) and the dengue group (3/161, 1.9 %). Clinical differences included the presence of rash, edema, and pruritus; in addition, differences in multiple biomarkers such as platelets, hemoglobin, indirect bilirubin, and serum sodium levels were documented. Conclusion: Rash on the palms and soles, edema and absence of pruritus, together with high levels of direct bilirubin and severe thrombocytopenia could be useful indicators to differentiate patients at RMSF advanced stages from those with dengue and chikungunya.

The genus Rickettsia in Mexico: Current knowledge and perspectives.

The genus Rickettsia encompasses 35 valid species of intracellular, coccobacilli bacteria that can infect several eukaryotic taxa, causing multiple emerging and re-emerging diseases worldwide. This work aimed to gather and summarise the current knowledge about the genus Rickettsia in Mexico, updating the taxonomy of the bacteria and their hosts by including all the records available until 2020, to elucidate host-parasite relationships and determine the geographical distribution of each Rickettsia species present in the country. Until now, 14 species of Rickettsia belonging to four groups have been recorded in Mexico. These species have been associated with 26 arthropod species (14 hard ticks, three soft ticks, two sucking lice, and seven fleas) and 17 mammal species distributed over 30 states in Mexico. This work highlights the high biological inventory of rickettsias for Mexico and reinforces the need to approach the study of this group from a One Health perspective.

Access to Palliative Care Services and Clinical Outcomes of Patients With Solid Malignancy-Associated Myelophthisis in a Resource-Limited Setting.

BACKGROUND: Myelophthisis (MPT) has been associated with a dreadful prognosis. Patients' access to palliative care (PC) and factors influencing its clinical outcomes are poorly described. Our aim was to analyze the impact of patient- and disease-specific characteristics on survival of patients with MPT and describe their use of PC in a resource-limited setting. METHODS: Retrospective study including patients with solid tumor MPT, diagnosed between 1996 and 2018. RESULTS: Seventy patients (median 58 years) were included. 58% were synchronously diagnosed with MPT at time of primary tumor diagnosis. Most common oncologic diagnoses were prostate (25.7%), gastrointestinal (20%), and breast (18.6%) neoplasms. Median overall survival (OS) was 1.9 months. Primaries other than prostate, breast, and lung (HR 1.37, 95% CI 1.15 - 1.8; p = 0.02) and transfusion requirements (HR 2.8, 95% CI 1.01 - 7.9; p = 0.04) were independently associated with decreased OS. Administration of multiple systemic therapeutic interventions (HR 0.15, 95% CI 0.06 - 0.39; p = 0.01) was the sole factor improving OS. Assessment by PC was pursued in 51.4% of patients. The median number of consults per patient was two, with no difference in assessment rate or consult number across different primaries (P = 0.96). Four cases of palliative sedation were reported, all performed by the primary care team. CONCLUSION: MPT is highly heterogeneous and risk stratification to optimize the use of therapeutic interventions in unison with palliative interventions is needed to maximize efforts toward improving patient quality of life. There is an alarming need of PC services in the multidisciplinary management of patients within developing regions.

Distribution and Occurrence of Amblyomma maculatum sensu lato (Acari: Ixodidae) and Rickettsia parkeri (Rickettsiales: Rickettsiaceae), Arizona and New Mexico, 2017-2019.

Amblyomma maculatum Koch sensu lato (s.l.) ticks are the vector of Rickettsia parkeri in Arizona, where nine cases of R. parkeri rickettsiosis have been identified since the initial case in 2014. The current study sought to better define the geographic ranges of the vector and pathogen and to assess the potential public health risk posed by R. parkeri in this region of the southwestern United States. A total of 275 A. maculatum s.l. ticks were collected from 34 locations in four counties in Arizona and one county in New Mexico and screened for DNA of Rickettsia species. Rickettsia parkeri was detected in 20.4% of the ticks, including one specimen collected from New Mexico, the first report of R. parkeri in A. maculatum s.l. from this state. This work demonstrates a broader distribution of A. maculatum s.l. ticks and R. parkeri in the southwestern United States than appreciated previously to suggest that R. parkeri rickettsiosis is underrecognized in this region.

Molecular Confirmation of Rickettsia parkeri in Amblyomma ovale Ticks, Veracruz, Mexico.

We found Rickettsia parkeri in Amblyomma ovale ticks collected in Veracruz, Mexico, in 2018. We sequenced gene segments of gltA, htrA, sca0, and sca5; phylogenetic reconstruction revealed near-complete identity with R. parkeri strain Atlantic Rainforest. Enhanced surveillance is needed in Mexico to determine the public health relevance of this bacterium.

Molecular evidence of Borrelia burgdorferi sensu stricto and Rickettsia massiliae in ticks collected from a domestic-wild carnivore interface in Chihuahua, Mexico.

Sixty-five wild carnivores and twenty free-roaming dogs from the Janos Biosphere Reserve (JBR), northwestern Chihuahua, Mexico, were inspected for ticks which were tested by molecular assays to identify Borrelia and Rickettsia infections. Overall, 45 ticks belonging to five taxa, including Dermacentor parumapertus, Ixodes hearlei, Ixodes kingi, Rhipicephalus sanguineus s.l., and Ornithodoros sp. were collected from 9.2% of the wild carnivores and 60% of the free-roaming dogs. Borrelia burgdorferi s.s. DNA was detected in an I. kingi tick collected from a kit fox (Vulpes macrotis), while Rickettsia massiliae was detected in two (6.5%) of the 31 Rh. sanguineus s.l. collected from free-roaming dogs. Our results revealed host associations between free-roaming dogs and wild carnivore hosts and their ticks in the JBR. The presence of the etiological agents of Lyme disease and spotted fever rickettsiosis in ticks raises the potential risk of tick-borne diseases at the human-domestic-wildlife interface in northwestern Mexico.

Enfermedad granulomatosa hepática / Hepatic granulomatous disease

Resumen Los granulomas son lesiones circunscritas compuestas principalmente por células mononucleares que surgen en respuesta a estímulos antigénicos pobremente degradables. Se encuentran en 2 a 15 % de las biopsias hepáticas; su hallazgo puede significar desde un fenómeno incidental, hasta la manifestación de una enfermedad sistémica de origen infeccioso, autoinmune o neoplásico. El cuadro clínico suele apuntar a la patología subyacente, sin embargo, la lista de condiciones asociadas es amplia y difiere con base en los antecedentes epidemiológicos y a las características basales del paciente. El elemento de mayor utilidad para su estudio es la historia clínica exhaustiva, con énfasis en viajes recientes, exposición de riesgo y consumo de fármacos o alimentos crudos o exóticos. El análisis histopatológico detallado puede auxiliar en la identificación de la etiología, por ejemplo, la presencia de granulomas epitelioides con necrosis caseosa indica tuberculosis y su ausencia, sarcoidosis; la abundancia de eosinófilos es señal de reacciones farmacológicas o infecciones parasitarias; la presencia de cuerpos extraños puede ser la causa de la enfermedad granulomatosa hepática. En este artículo describimos los aspectos clínico-patológicos básicos de esta enfermedad y proveemos un breve resumen de las etiologías más comunes, principalmente en la región de Latinoamérica.

Abstract Granulomas are circumscribed lesions mainly composed of mononuclear cells that arise in response to poorly degradable antigenic stimuli. They are found in 2-15 % of liver biopsies and the meaning of their finding can range from an incidental phenomenon to the manifestation of a systemic disease of infectious, autoimmune or neoplastic origin. Clinical presentation usually points at the underlying pathology; however, the list of associated conditions is extensive, and differs based on patient epidemiological history and baseline characteristics. The most useful element for their study is a thorough medical history, with an emphasis on recent trips, exposures and consumption of drugs or raw or exotic foods. Detailed histopathological analysis may help identify the etiology. For example, the presence of epithelioid granulomas with caseous necrosis indicates tuberculosis and, its absence, sarcoidosis; eosinophil abundance can be associated with drug reactions or parasitic infections; and the presence of foreign bodies can be the cause of granulomatous liver disease (GLD). In this article, we describe the basic clinical-pathological aspects of GLD, and provide a brief summary of the most common etiologies, with an emphasis on the Latin-American region.

Rickettsia parkeri and Candidatus Rickettsia andeanae in Tick of the Amblyomma maculatum Group, Mexico.

We report Rickettsia parkeri and Candidatus Rickettsia andeanae in ticks of the Amblyomma maculatum group collected from dogs in Sonora, Mexico. Molecular characterization of these bacteria was accomplished by DNA amplification and sequence analysis of portions of the rickettsial genes gltA, htrA, ompA, and ompB.

The Amblyomma maculatum Koch, 1844 (Acari: Ixodidae) group of ticks: phenotypic plasticity or incipient speciation?

BACKGROUND: The goal of this study was to reassess the taxonomic status of A. maculatum, A. triste and A. tigrinum by phylogenetic analysis of five molecular markers [four mitochondrial: 12S rDNA, 16S rDNA, the control region (DL) and cytochrome c oxidase 1 (cox1), and one nuclear: ribosomal intergenic transcribed spacer 2 (ITS2)]. In addition, the phenotypic diversity of adult ticks identified as A. maculatum and A. triste from geographically distinct populations was thoroughly re-examined. RESULTS: Microscopic examination identified four putative morphotypes distinguishable by disjunct geographical ranges, but very scant fixed characters. Analysis of the separated mitochondrial datasets mostly resulted in conflicting tree topologies. Nuclear gene sequences were almost identical throughout the geographical ranges of the two species, suggesting a very recent, almost explosive radiation of the terminal operational taxonomic units. Analysis of concatenated molecular datasets was more informative and indicated that, although genetically very close to the A. maculatum - A. triste lineage, A. tigrinum was a monophyletic separate entity. Within the A. maculatum - A. triste cluster, three main clades were supported. The two morphotypes, corresponding to the western North American and eastern North American populations, consistently grouped in a single monophyletic clade with many shared mitochondrial sequences among ticks of the two areas. Ticks from the two remaining morphotypes, south-eastern South America and Peruvian, corresponded to two distinct clades. CONCLUSIONS: Given the paucity of morphological characters, the minimal genetic distance separating morphotypes, and more importantly the fact that two morphotypes are genetically indistinguishable, our data suggest that A. maculatum and A. triste should be synonymized and that morphological differences merely reflect very recent local adaptation to distinct environments in taxa that might be undergoing the first steps of speciation but have yet to complete lineage sorting. Nonetheless, future investigations using more sensitive nuclear markers and/or crossbreeding experiments might reveal the occurrence of very rapid speciation events in this group of taxa. Tentative node dating revealed that the A. tigrinum and A. maculatum - A. triste clades split about 2 Mya, while the A. maculatum - A.triste cluster radiated no earlier than 700,000 years ago.

Fatal case of co-infected of rickettiosis and dengue virus in Mexico / Caso fatal de coinfectada de rickettsiosis y virus del dengue en México

Background: Rocky Mountain spotted fever (RMSF) is a disease spread by an infected tick and it is lethal if patient is not treated on time. Symptom similarities with other exanthematous diseases may delay the diagnosis, which leads to its mortality. Clinical case: We show the lethal case of a patient with medical record of high blood pressure and no history of travel, who lived in Sonora, Mexico. At the beginning, it was suspected that the patient had a dengue virus infection, which was confirmed positive by an ELISA test. Patient's rapid deterioration, multi-organic failure and the characteristics of her exanthema led to the suspicion of the presence of RMSF. We started doxycycline treatment; however, patient died after seven days of evolution. It was confirmed a co-infection of Rickettssia spp. and dengue virus. Conclusion: In rickettsial endemic zones, treatment with doxycycline should be employed in patients with similar symptoms, even though there is evidence of the presence of other etiologic agents.

Introducción: La fiebre maculosa de las Montañas Rocosas (FMMR) es una enfermedad transmitida por garrapatas y es fatal si el paciente no recibe tratamiento. La similitud de sus síntomas con otras enfermedades febriles exantemáticas puede retrasar la sospecha diagnóstica, lo cual contribuye a su mortalidad. Caso clínico: Presentamos el caso fatal de una paciente con antecedente de hipertensión arterial y sin historial de viajes, que era residente de Sonora, México. Al principio se sospechó la presencia de una infección por virus del dengue, confirmada por prueba de ELISA. Su rápido deterioro, la falla multiorgánica y las características de su exantema orientaron la sospecha de FMMR. Se inició tratamiento con doxiciclina; sin embargo, la paciente falleció al séptimo día de evolución. Se confirmó una coinfección de Rickettssia spp. y virus del dengue. Conclusión: En zonas donde la Rickettssia es endémica, el tratamiento con doxiciclina debería iniciarse ante un paciente con síntomas compatibles, aun cuando se tenga evidencia de la presencia de otros agentes etiológicos.

Rickettsia parkeri in Dermacentor parumapertus Ticks, Mexico.

During a study to identify zoonotic pathogens in northwestern Mexico, we detected the presence of a rickettsial agent in Dermacentor parumapertus ticks from black-tailed jackrabbits (Lepus californicus). Comparison of 4 gene sequences (gltA, htrA, ompA, and ompB) of this agent showed 99%-100% identity with sequences of Rickettsia parkeri.

[A fatal case series of Rocky Mountain spotted fever in Sonora, México].

INTRODUCTION: Rocky Mountain spotted fever is a highly lethal infectious disease, particularly if specific treatment with doxycycline is given belatedly. OBJECTIVE: To describe the clinical profile of fatal Rocky Mountain spotted fever cases in hospitalized patients in the state of Sonora, México. MATERIALS AND METHODS: We conducted a cross-sectional study on a series of 47 deaths caused by Rickettsia rickettsii from 2013 to 2016. The diagnosis of Rocky Mountain spotted fever was confirmed in a single blood sample by polymerase chain reaction (PCR) or by a four-fold increase in immunoglobulin G measured in paired samples analyzed by indirect immunofluorescence. Clinical and laboratory characteristics were compared stratifying subjects into two groups: pediatric and adult. RESULTS: There were no differences in clinical characteristics between groups; petechial rash was the most frequent sign (96%), followed by headache (70%) and myalgia (67%). Although that doxycycline was administered before the fifth day from the onset of symptoms, death occurred in 55% of patients. In clinical laboratory, thrombocytopenia, and biomarkers of liver acute failure and acute kidney failure were the most frequent. CONCLUSION: Rocky Mountain spotted fever remains as one of the most lethal infectious diseases, which may be related not only to the lack of diagnostic suspicion and delayed administration of doxycycline, but to genotypic characteristics of Rickettsia rickettsii that may play a role in the variability of the fatality rate that has been reported in other geographical regions where the disease is endemic.

Rocky Mountain Spotted Fever and Pregnancy: Four Cases from Sonora, Mexico.

We present a series of four pregnant women with Rocky Mountain spotted fever (RMSF) that occurred in Sonora, Mexico, during 2015-2016. Confirmatory diagnoses were made by polymerase chain reaction or serological reactivity to antigens of Rickettsia rickettsii by using an indirect immunofluorescence antibody assay. Each patient presented with fever and petechial rash and was treated successfully with doxycycline. Each of the women and one full-term infant delivered at 36 weeks gestation survived the infection. Three of the patients in their first trimester of pregnancy suffered spontaneous abortions. RMSF should be suspected in any pregnant woman presenting with fever, malaise and rash in regions where R. rickettsii is endemic.