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Background: Primary gastric lymphomas account for less than 5% of non-Hodgkin lymphomas (NHL). The vast majority of primary gastric lymphomas are high-grade B-cell lymphomas. Primary gastric T-cell lymphomas are very rare and are usually associated with HTLV-1 infection in endemic regions. Material and methods. We describe the case of a middle-aged female patient who presented with pneumoperitoneum due to a perforated gastric ulcer, wasting syndrome, and skin and oral lesions. Results. Histopathology and immunohistochemistry confirmed primary gastric T-cell lymphoma with skin involvement. The serology for HTLV-1, Epstein-Barr virus and HIV were negative. Conclusion. The aim of this report is to present this extremely rare presentation of primary gastric lymphoma. Introducción: Los linfomas gástricos primarios representan menos del 5% de los linfomas no Hodgkin (LNH). La gran mayoría de linfomas gástricos primarios son linfomas de células B de alto grado. Los linfomas gástricos primarios de células T son muy raros y usualmente se asocian a infección por HTLV-1 en regiones endémicas. Material y método. Describimos el caso de una paciente mujer de mediana edad que se presentó con neumoperitoneo debido a ulcera gástrica perforada, síndrome consuntivo y lesiones cutáneas y orales. Resultados. La histopatología e inmunohistoquímica confirmaron linfoma gástrico primario de células T con compromiso cutáneo. La serología para HTLV-1, virus del Epstein-Barr y VIH fueron negativas. Conclusión. La finalidad de este reporte es dar a conocer esta forma de presentación sumamente rara de linfoma gástrico primario.

El Trastorno por Uso de Alcohol (TUA) es una enfermedad que puede cursar con múltiples complicaciones. El sistema inmunológico se ve comprometido por el abuso de alcohol, hecho que predispone al desarrollo de múltiples enfermedades, entre las que destacan las infecciosas. En la inmunidad adquirida, el consumo crónico de alcohol se ha visto relacionado con alteraciones en el número, función y fenotipo de los linfocitos B y T. El objetivo principal de esta Tesis doctoral es caracterizar las alteraciones del linfocito T, célula clave de la inmunidad adquirida, en pacientes con TUA. Los resultados obtenidos se pueden ver reflejados en dos artículos científicos publicados en la revista Drug and Alcohol Dependence. En el primer artículo, se analizan las alteraciones de las principales subpoblaciones linfocitarias T en una serie de pacientes admitidos a tratamiento del TUA entre 2002 y 2012. En concreto, se analizan linfocitos T CD4+, CD8+, Dobles Positivos (CD4+/CD8+) y Dobles Negativos (CD4-/CD8-). Los resultados ponen de manifiesto que las alteraciones linfocitarias cuantitativas son frecuentes en este tipo de pacientes, aparentemente asintomáticos, que vienen a tratarse del TUA. De hecho, una cuarta parte presentan niveles elevados de linfocitos CD8+, un 50% muestran bajo número de células Doble Negativas y un 13% presentan linfopenia de linfocitos CD4+, con lo que ello implica en el riesgo de sufrir infecciones oportunistas. El manuscrito plantea la relevancia del análisis de subpoblaciones linfocitarias en pacientes con TUA para identificar aquéllos con mayor riesgo de infecciones. El segundo artículo se centra en analizar indicadores de activación del LT, comparando su expresión en dichos pacientes y en controles sanos. Mediante citometría de flujo se utiliza una combinación de marcadores linfocitarios de superficie (CD38 y HLA-DR). Los resultados ponen de manifiesto que pacientes con TUA tienen un exceso de activación de linfocitos CD8+ y que el exceso de activación está inversamente relacionado con el número absoluto de linfocitos CD4+., Alcohol Use Disorder (AUD) is a disease with multiple associated complications. The immune system can be compromised by alcohol abuse and alterations of the innate and adaptive immunity may predispose to the development of infections. Related to the acquired immunity, chronic alcohol consumption has been associated with alterations in the number, function and phenotype of B and T lymphocytes. The aim of this Thesis is to better characterize the alterations of T lymphocyte subsets in patients with AUD. The results obtained in this research have been published as original articles in the journal Drug and Alcohol Dependence. In the first article, we aimed to analyze the prevalence and factors associated with quantitative alterations of T lymphocytes subpopulations in 238 patients admitted to treatment of AUD between 2002 and 2012. Specifically, CD4+, CD8+, Double Positive (CD4+/CD8+) and Double Negative (CD4-/CD8-) lymphocytes are analyzed in this case series. The results show that quantitative T-cell alterations are frequent and, in fact, 25% of patients have increased numbers of CD8+, 50% have low Double Negative cells and 13% have decreased number of CD4+ cells. Therefore, the article discuss the importance of including the analysis of the T-cell subpopulations in individuals with chronic AUD to better identify those at high risk of infections. The second article focuses on markers of LT activation when comparing their expression in AUD patients and healthy controls. We used a combination of cell surface markers (CD38 and HLA-DR). Results show that patients with AUD have an excess of CD8+ T-cell activation compared to healthy controls and that the excess of activation is inversely correlated with the absolute number of CD4+ lymphocytes.

Se informa el caso de una mujer de 80 años con hallazgo incidental de masa abdominal en mesogastrio. Se le realiza resección de intestino delgado por sospecha de absceso con síndrome adherencial. El estudio patológico de la pieza quirúrgica demostró compromiso por linfoma no Hodgkin T monomórfico CD56+. Los linfomas T del tubo digestivo son inusuales; corresponden al 5% de las neoplasias linfoides de esta localización. El linfoma intestinal T monomórfico CD56+ corresponde a 10-20% de los linfomas T intestinales. Se presenta en regiones donde la enfermedad celiaca es infrecuente y no se asocia a enteropatía. Su curso es agresivo y habitualmente se manifiesta como una emergencia quirúrgica por obstrucción o perforación intestinal. 80 year old woman with incidental finding of abdominal mass in midgut, in which small bowel resection is performed for suspected abscess associated to surgical adhesions. Pathological examination of the surgical specimen showed a monomorphic CD56+ T cell lymphoma. T-cell lymphomas of the digestive tract are rare, accounting for 5% of all lymphoid neoplasms in this location. Monomorphic CD56+ intestinal T cell lymphoma corresponds to 10 - 20% of T cell intestinal lymphomas. This tumor occurs in regions where celiac disease is rare and it is not associated with enteropathy. Its course is aggressive and usually manifests as a surgical emergency by intestinal obstruction or perforation.

Background: Human T-lymphotropic virus-1 (HTLV-1) infection has been associated with the pathogenesis of cutaneous T cell lymphomas (CTCL). Aim: To search for HTLV-1 DNA in skin biopsies of patients with CTCL. Material and Methods: A retrospective study was conducted using 25 biopsies of patients with CTCL. DNA was extracted from lymphoid tissue by microdissection. A nested PCR was conducted to detect HTLV-1 genome using primers for the tax region. As negative controls, four cases of superficial perivascular dermatitis were chosen. As positive controls, five cases of T-cell leukemia/lymphoma (ATCL) were studied. Results: A positive reaction was found in 3 of 25 cases. These biopsies corresponded to a case of Mycosis Fungoides, a case of CD30 (-) T-cell lymphoma and a case of lymphomatoid papulosis. Search was negative in the four cases of superficial perivascular dermatitis and positive in four cases of adult T-cell leukemia/lymphoma (ATCL). Conclusions: HTLV-1 DNA search in tissues is a useful tool recommended to study T-cell lymphomas. HTLV-1 infection only occurs in sporadic cases but may contribute to tumor aggressiveness and prognosis.

Con base en ecuaciones diferenciales no lineales se formula un modelo matemático que describe la dinámica de interacción del VIH con células T CD4, que se considera que pueden ser activadas o no activadas en el reconocimiento de partículas virales; en cualquiera de los dos casos, son susceptibles a la infección con el virus. Se encuentran los puntos de equilibrio del sistema y en el caso particular del equilibrio trivial o de ausencia de infección, se determina su estabilidad local con base en el número básico de reproducción. Se efectúa además la simulación numérica del modelo para establecer el comportamiento que presentan las células infectadas y la carga viral, frente a variaciones de algunos de los parámetros. Finalmente, se reformula el modelo considerando respuesta inmune celular de tipo citotóxico y se realiza la simulación numérica. Nonlinear differential equations were used for formulating a mathematical model describing the dynamics of HIV interaction with CD4 T-cells which are considered to be activated or not activated during recognition of viral particles; in either case they are susceptible to HIV infection. The system's equilibrium points were found and local stability was determined for trivial equilibrium or the absence of infection based on the basic reproduction number. The model was used for numerical simulation to show infected cell and viral load patterns regarding the variations of some parameters. The model was then reformulated, considering a cytotoxic cellular immune response and numerical simulation was run again.

Female patient FPM, 53 year-old, housewife, born in Amazonas, Peru, resident in Lima since teenager, was admitted at Emergency room due to colicky abdominal pain and abdominal tumour about 8 x 5 x 5 cm, in mesogastric area, mobile and painful. She had vomiting in two opportunities and lost undetermined weight. During surgery we found terminal ileum intussuception into the ascending large bowel and a tumour mass in terminal ileum. Pathology report informed high degree of malignancy no-Hodgkin T-cell phenotype lymphoma. Paciente de sexo femenino, de 53 años de edad, ama de casa, natural del Departamento de Amazonas, procedente de Lima, donde radicaba desde su juventud, fue admitida en Emergencia del hospital por presentar dolor abdominal tipo cólico persistente, en mesogastrio, con irradiación al hemiabdomen superior. Además, presentaba tumoración abdominal, de más o menos 8 x 5 x 5 cm, en mesogastrio, móvil, dolorosa y dolor a la descompresión en fosa iliaca derecha; posteriormente, se agregó vómitos en dos oportunidades y pérdida de peso no cuantificado. En el intraoperatorio, se encontró intususcepción del íleon terminal hacia colon ascendente y tumoración de íleon distal. La anatomía patológica de la tumoración demostró linfoma no Hodgkin, fenotipo de células T de grado alto de malignidad.

Background: Chronic lymphoproliferative disorders include a variety of diseases which are often a diagnostic problem for clinical hematologists. Aim: To study prospectively the distribution and incidence of chronic lymphoproliferative disorders in Chile and compare them with those of other Western, Latin American and Oriental countries. Patients and methods: A group of 132 patients were studied in a 36 months period (1999-2001), with a panel of monoclonal antibodies. A score for chronic lymphocytic leukemia was employed to differentiate it from other B-cell disorders. Results: The median age was 63 years old (range 32-94). Most patients had B-cell tumors (109) and the rest (23), T-cell tumors (82% vs 18%). Forty five percent of patients with B-cell tumors had a chronic lymphocytic leukemia (CLL), while the others were disseminated lymphomas. The incidence of T-cell tumors was slightly higher than that of other Western countries. Noteworthy is that the most common of these disorders was adult T cell leukemia/lymphoma (ATLL), in concordance with the high HTLV-1 seroprevalence in Chile. Conclusions: A morphologic, immunophenotypic and pathological study in a large number of patients with chronic lymphoproliferative disorders in Chile, shows a relatively low incidence of CLL when compared to other chronic B-cell tumors and a high representation of ATLL associated to HTLV-1 infection, compared with other Western countries. The lower incidence of CLL in our study might be due to patient's selection and/or underdiagnosis of this disease as a substantial proportion of CLL are asymptomatic (Rev Méd Chile 2003; 131: 291-8).