Pneumocystis jirovecii pneumonia (PCP) is a potential complication of immunosuppression. Crohn's disease (CD) is an immune granulomatous disorder characterized by transmural inflammation that can affect any part of the gastrointestinal tract. Its treatment is based on steroids and immunosuppressants but in non-responders, biologic compounds such as anti-tumor necrosis factor alpha (TNF) antibodies have been used. Neutralization of TNF causes a decrease in the inflammatory response but increases susceptibility to opportunistic infections such as fungal infections. We report a young male with chronic diarrhea, fever and weight loss who was diagnosed with CD and began conventional treatment with immunosuppressants, but due to lack of response after several weeks, biologic therapy with adalimumab was initiated. Seven weeks later he developed persistent fever and upper respiratory symptoms. After chest CT, bronchoscopy and bronchial lavage, P. jirovecii was identified by silver staining and confirmed by immunofluorescence. To our knowledge this is the second case of pneumocystosis associated with the use of adalimumab in CD and the first reported Mexican case confirmed by microbiological and immunological studies in this setting.

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The biotechnology-derived medicines known as biosimilars are defined as non-originator treatments that have demonstrated quality, efficacy, and safety comparable to the reference biologic drug. Clinical trials have shown that the infliximab biosimilar, CT-P13, and the candidates for the adalimumab biosimilars, ABP 501 and ZRC 3197, are not significantly different, with respect to efficacy and safety, from the originator drugs in patients with other autoimmune diseases. However, controversy has arisen over the use of biosimilars in inflammatory bowel disease, due to the incipient evidence not only in patients with no previous biotechnology treatment, but also in patients in remission, that could be switched to a biosimilar for non-medical reasons. The present review is the first critical analysis by different specialists in the area of gastroenterology on the use of biosimilars in inflammatory bowel disease, the evidence on interchangeability, the extrapolation of indications, efficacy, safety, immunogenicity, and the clinical impact of the Mexican health regulations. The aim of our review was to make the positioning and recommendations of these new therapeutic options known, given that they have a potential cost-benefit for both patients and healthcare institutions.

Aim: Non-ampullary duodenal epithelial tumor is rare. For treatment planning, it is important to distinguish between duodenal adenoma and duodenal cancer. However, histological diagnosis using endoscopic biopsy is sometimes difficult because of inadequate sampling of cancerous tissue within the adenomatous lesion. Furthermore, fibrosis after endoscopic biopsy is reported to make endoscopic resection difficult. The endocytoscopy system (ECS) is a novel ultra-high-magnification endoscope that allows observation at the cellular level. Our previous ECS investigation of duodenal lesions in patients with familial adenomatous polyposis revealed that disappearance of goblet cells and spindle-shaped nuclei with loss of polarity of the nuclear arrangement were characteristic features of duodenal adenoma. In addition, round duct openings and fingerlike projections were observed in tubular adenoma and villous adenoma, respectively. Here, we evaluated the ECS features of non-ampullary mucosal duodenal cancer (NAMDC). Materials and methods: We retrospectively investigated six cases of histologically proven NAMDC observed by ECS using 2% methylene blue for vital staining of cells in vivo. We evaluated the presence or absence of goblet cells, tubular structures or villous structure, loss of nuclear arrangement polarity, nuclear enlargement, and nuclear shape. All of the cases were surgically resected mucosal duodenal cancers and histological investigation included immunohistochemical staining for CD10, MUC2, MUC5AC, and MUC6. Results: Macroscopically, all of the cases were the elevated type with a median diameter of 48.5 mm (range 25-70 mm). Immunohistochemical analysis suggested that one case involving the duodenal bulb was the gastric (mixed) type, whereas the other five cases were the intestinal type and located in the 2 nd or 3 rd portion of the duodenum. Vital staining of the case considered to be the gastric type was insufficient for ECS observation because of surface mucus. All five cases of intestinal-type duodenal cancer showed a villous structure, disappearance of goblet cells and enlarged nuclei with loss of polarity. Tubular structures were admixed in four of these cases (Figure 1). Four cases were found to have oval-shaped nuclei (Figure 2), and one case had spindle-shaped nuclei. Cases with spindle-shaped nuclei in most of the lesion were diagnosed histologically as cancer in adenoma where the adenomatous component was dominant in the cancerous area. Conclusion: Oval-shaped nuclei and nuclear enlargement are the characteristic features of NAMDC revealed by ECS, and included in the histological criteria for diagnosis. ECS may enable omission of biopsy histology for histological diagnosis of NAMDC.

Antecedentes: la incidencia de la inmunodeficiencia común variable (IDCV) es de 1 por cada 15,000 a 117,000 casos, sin predominio de género. La incidencia de manifestaciones gastrointestinales en estos pacientes es de 20 a 60% y pueden ser la primera y única manifestación clínica de IDCV. En México existe escasa información en relación con el tipo y frecuencia de alteraciones gastrointestinales que padecen los pacientes adultos con IDCV.Objetivo: determinar la prevalencia de alteraciones gastrointestinales en pacientes adultos con inmunodeficiencia común variable.Material y método: estudio descriptivo, observacional y transversal en el que participaron pacientes con inmunodeficiencia común variable de la Clínica de Inmunodeficiencias del Servicio de Alergia e Inmunología Clínica del Hospital de Especialidades, Centro Médico Nacional Siglo XXI. A todos los pacientes se les aplicó un cuestionario de síntomas gastrointestinales y se les realizaron estudios de laboratorio, gabinete, endoscopia y prueba de aliento para determinar sobrepoblación bacteriana.Resultados: evaluamos 17 pacientes, 8 hombres y 9 mujeres, con edad promedio de 36 años y diagnóstico definitivo de inmunodeficiencia común variable de acuerdo con criterios internacionales. El 59% refirió dolor abdominal, 53% distensión abdominal y 17.6% estreñimiento. El 47% tenía diarrea crónica, en dos de ellos (11.8%) acompañada  de pujo rectal. Las enfermedades gastrointestinales de esta población fueron: 18% diarrea crónica, enfermedad celiaca y sobrepoblación bacteriana, 24% trastorno funcional digestivo, 12% estreñimiento, 6% dispepsia. Sólo un paciente (6%) no tenía síntomas gastrointestinales.Conclusión: la prevalencia de las enfermedades gastrointestinales en pacientes adultos con inmunodeficiencia común variable fue de 94%, sin predominio de género. Debido a la frecuencia de manifestaciones gastrointestinales, es importante realizar protocolos de estudio al respecto para iniciar de manera temprana su diagnóstico y tratamiento.