Immunotolerance in liver transplantation: a primer for the clinician

The use of immunosuppressive medications for solid organ transplantation is associated with cardiovascular, metabolic, and oncologic complications. On the other hand, the development of graft rejection is associated with increased mortality and graft dysfunction. Liver transplant recipients can withdraw from immunosuppression without developing graft injury while preserving an adequate antimicrobial response - a characteristic known as immunotolerance. Immunotolerance can be spontaneously or pharmacologically achieved. Contrary to the classic dogma, clinical studies have elucidated low rates of true spontaneous immunotolerance (no serologic or histological markers of immune injury) among liver transplant recipients. However, clinical, serologic, and tissue biomarkers can aid in selecting patients in whom immunosuppression can be safely withdrawn. For those who failed an immunosuppression withdrawal trial or are at high risk of rejection, pharmacological interventions for immunotolerance induction are under development. In this review, we provide an overview of the mechanisms of immunotolerance, the clinical studies investigating predictors and biomarkers of spontaneous immunotolerance, as well as the potential pharmacological interventions for inducing it.

Calculated Versus Measured Urine Osmolarity: Accuracy of Estimated Urine Density

BACKGROUND

Urine osmolarity (OsmU) is the gold standard for the evaluation of the kidney's urine concentration capacity; nevertheless, urinary density (UD) is often used as a surrogate for its estimation.

OBJECTIVE

The objective of this study was to analyze the accuracy of UD in estimating OsmU.

MATERIALS AND METHODS

A transversal study including patients with simultaneous determination of UD measured with refractometry and OsmU measured by osmometer (OsmUm). We multiplied the last two digits of the UD by 35, 30, 32, 33.5, and 40 to estimate OsmU; the estimates were considered precise if the value was ± 30 mOsm/kg from the OsmUm. A Bland-Altman analysis was conducted.

RESULTS

Among 205 patients, there was no difference between OsmUm and the estimated form when using a factor of 33.5 (p = 0.578). When analyzing by the absence or presence of proteinuria and/or glycosuria, there were no differences when using the factors 35 (p = 0.844) and 32 with adjusted UD (p = 0.898). In the linear correlation analysis, values for Pearson's r = 0.788 and r2 = 0.621 were obtained (p < 0.001). The areas under the curve obtained by the receiver operating characteristics curves to estimate urine osmolarity values < 100 and > 600 mOsm/kg were > 0.90.

CONCLUSION

The estimation of the OsmU from UD showed adequate performance. If an osmometer is unavailable, we recommend using the factor 35 for clean samples and 32 with adjusted UD for samples with proteinuria and/or glycosuria.

Pneumonia in patients with systemic lupus erythematosus: Epidemiology, microbiology and outcomes

Background and objective Pneumonia remains the main cause of mortality in patients with systemic lupus erythematosus (SLE). The aim of the study was to establish the clinical characteristics, microbiology and risk factors for poor prognosis in patients with SLE and pneumonia. Methods We reviewed medical records of patients with SLE (American College of Rheumatology criteria) and pneumonia who attended the emergency room in a single tertiary care center (January 2010-March 2015). We collected demographics, treatment and disease activity (SLEDAI-2K) data. Severity scales of pneumonia (CURB-65 (acronym for risk factors measured: confusion, urea nitrogen, respiratory rate, blood pressure, 65 years of age and older) and Pneumonia Severity Index (PSI)) were obtained. A negative composite outcome was defined as need for mechanical ventilation, septic shock or death secondary to pneumonia up to 30 days after discharge. We conducted a univariate and multivariable analysis. Results We studied 158 patients (76% women) with 187 episodes of pneumonia. There were no differences in age, SLE duration, SLE activity, treatment or comorbidities between patients with negative composite outcome vs the other group. In 53 episodes, patients presented with a negative composite outcome. Of these, 46 (24.6%) required intubation, 13 (7%) developed shock and 12 (6.4%) died. The most common bacteria isolated was S. aureus, and we observed a high percentage of nonhabitual microorganisms. Fifteen percent of patients who presented with a negative outcome had low values on CURB-65 and PSI scales. Conclusion Patients with SLE and pneumonia have a high risk of complications and present with a high percentage of nonhabitual microorganisms. Severity scales for pneumonia can misclassify as low risk SLE patients with poor prognosis.

Electrolyte and Acid-Base Disturbances in End-Stage Liver Disease: A Physiopathological Approach

Electrolyte and acid-base disturbances are frequent in patients with end-stage liver disease; the underlying physiopathological mechanisms are often complex and represent a diagnostic and therapeutic challenge to the physician. Usually, these disorders do not develop in compensated cirrhotic patients, but with the onset of the classic complications of cirrhosis such as ascites, renal failure, spontaneous bacterial peritonitis and variceal bleeding, multiple electrolyte, and acid-base disturbances emerge. Hyponatremia parallels ascites formation and is a well-known trigger of hepatic encephalopathy; its management in this particular population poses a risky challenge due to the high susceptibility of cirrhotic patients to osmotic demyelination. Hypokalemia is common in the setting of cirrhosis: multiple potassium wasting mechanisms both inherent to the disease and resulting from its management make these patients particularly susceptible to potassium depletion even in the setting of normokalemia. Acid-base disturbances range from classical respiratory alkalosis to high anion gap metabolic acidosis, almost comprising the full acid-base spectrum. Because most electrolyte and acid-base disturbances are managed in terms of their underlying trigger factors, a systematic physiopathological approach to their diagnosis and treatment is required.

Perioperative management of patients with antiphospholipid syndrome: a single-center experience

The objective was to describe the management and risk factors for complications of antiphospholipid syndrome (APS) patients who underwent a surgical procedure in a single center. We reviewed medical records of all patients with primary or secondary APS who underwent an elective surgery during a 6-year period. Demographical data, management of anticoagulation and complications were recorded. We identified 43 patients, mean age 37.9 ± 8.9 years, who underwent a total of 48 elective surgeries. All patients had history of at least one thrombotic event and were under vitamin K antagonists. Before surgery, all patients received bridging therapy with intravenous infusion of heparin or low molecular weight heparin (LMWH). Among the LMWH group, 36 had a full anticoagulation regimen and nine prophylactic doses. In 62% of the surgeries, we identified an optimal management of periprocedural anticoagulation according to guidelines. Overall six patients had severe bleeding and three thrombotic complications (full anticoagulation regimen n = 2 and prophylactic dose group n = 1). Patients with optimal management of anticoagulation experienced less thrombotic and hemorrhagic complications (7 vs. 33%; OR 0.14, 95% CI 0.02-0.81; p = 0.040) and patients with INR ≤1.5 at surgery had fewer episodes of major bleeding (6 vs. 29%; OR 0.19, 95% CI 0.02-0.98; p = 0.050). All three thrombotic events occurred in patients with INR ≤1.5. Proper management of anticoagulation based on guidelines is associated with less complications in patients with APS. Notwithstanding the proper use of bridging therapy, some patients may develop thrombotic complications.

Diminished expression of complement regulatory proteins (CD55 and CD59) in lymphocytes from systemic lupus erythematosus patients with lymphopenia

CD55 and CD59 are glycophosphatidylinositol-anchored proteins with complement inhibitory properties. Lymphopenia in systemic lupus erythematosus (SLE) has been associated with autoantibodies targeting nuclear antigens. The aim of this study was to evaluate the surface density of CD55 and CD59 in T and B lymphocytes from patients with SLE and lymphopenia and its possible correlation with the presence of common SLE autoantibodies. Flow cytometric analyses were performed on CD55 and CD59 stained CD3 and CD19 cells from 40 SLE patients, 30 with lymphopenia and 10 without it, and 25 healthy controls. Autoantibodies were detected in the sera by enzyme linked immunosorbent assay. The mean fluorescence intensity of CD55 and CD59 in T and B cells was significantly diminished in SLE patients with lymphopenia when compared with healthy subjects. Interestingly, the opposite was found in T and B cells from non-lymphopenic SLE patients. Although there was no correlation between CD55 and CD59 surface density and the presence of any specificity of the autoantibodies tested, higher titres of anti-dsDNA, anti-SM and anti-ribosomal p antibodies were significantly associated with lymphopenia. The deficiency of CD55 and CD59 expression may play a role in the pathophysiology of lymphopenia, most likely by increasing the susceptibility of cells to complement mediated cytolysis.

Persistent hepatic encephalopathy secondary to portosystemic shunt occluded with Amplatzer device

Hepatic encephalopathy is a frequent complication of cirrhosis, when this event becomes persistent, treatment compliance should be verified and any precipitating factor need to be identified. Also the presence of portosystemic shunts, which are a rare cause of decompensation or persistence hepatic encephalopathy need to be ruled out. In this paper we report the case of a 57 year old man with persistent hepatic encephalopathy secondary to the presence of a porto-onfalo-femoral shunt successfully closed with the placement of an Amplatzer device.

Sarcoidosis: a single hospital-based study in a 24-year period

BACKGROUND

Clinical presentation of sarcoidosis varies according to race and geographical area. We describe the clinical spectrum and outcome of sarcoidosis in Mexican patients compared with other populations.

METHODS

We reviewed the medical charts of 21 patients with sarcoidosis seen at a referral hospital in 1989-2012; organ involvement was assessed using the ACCESS instrument. We compared our results with the ACCESS and Latin American studies. We used descriptive statistics and reported odd ratios with 95% CI.

RESULTS AND CONCLUSION

Fifty-two percent were women; median age was 31 years; median time to diagnosis, 5.5 months. Frequency of organ involvement was: constitutional symptoms 62%, lungs 66.6%, skin 42.8%, bone marrow 23.4%, lymph node 19%, liver 19%, and eye 19%. After one year of follow-up, 47.5% of patients were asymptomatic without treatment, 38% asymptomatic on treatment, and 14.2% symptomatic on treatment. In our patients, pulmonary involvement was lower (66.6 vs. 94.9%; p = 0.001) and cutaneous (42.8 vs. 15.8%; p = 0.003) and bone marrow (23.4 vs. 4.7%; p = 0.001) were higher than in the ACCESS cohort. Data regarding Latin American populations was scarce. The clinical spectrum of sarcoidosis in our population differed from other studies, with a higher frequency of cutaneous sarcoidosis and less pulmonary involvement.

Clinical and Immunopathologic Profile of Mexican Patients with IgG4 Autoimmune Pancreatitis

Autoimmune pancreatitis is part of the spectrum of IgG4-associated diseases. Its diagnostic criteria and histological subtypes have been formally proposed recently and although based on current data it has been suggested that there are differences in clinical presentation among populations, more research is needed to properly establish if this heterogeneity exists. In this paper, we describe 15 cases of autoimmune pancreatitis diagnosed at a Mexican centre of reference, all of them associated to the lymphoplasmocytic sclerosing pancreatitis variant. The mean age at the onset of symptoms was 47.5 ± 14.4 years, and 53% of patients were male. The main manifestations were weight loss (87%), obstructive jaundice (53%), and acute (27%) and chronic (27%) pancreatitis. Only 20% of patients had high IgG4 serum levels at the time of diagnosis. All patients receiving prednisone responded favourably, both in their pancreatic and extrapancreatic manifestations. Clinical manifestations of Mexican patients showed certain differences with respect to those usually reported.

CD8+ chronic lymphocytic leukemia: an extensive characterization of a bizarre hybrid neoplasia

Atypical chronic lymphocytic leukemia (CLL) expressing the CD8 antigen have a frequency of less than 0.5% of all cases, however, they are not yet been fully characterized. Herein a CD8+ CLL case was extensively studied. Besides the classical CLL antigen expression, an unusual presence of surface markers such as CD11c, CD56, and CD154 was observed. Moreover, gene expression of chemokine receptors belonging to the CCR family were clearly evidenced as well as mRNA for both, Th1 and Th2 cytokines. Likewise, granzyme A, B and perforin gene expression, cytotoxic T cell or NK enzymes were found. The intricate profile of membrane molecules and gene expression suggest that it could be favorable, rather than deletereous, for the maintainance of the neoplastic process.

Deficiency of red cell bound CD55 and CD59 in patients with systemic lupus erythematosus

CD55 and CD59 are glycosylphosphatidylinositol-anchored proteins with complement inhibitory properties. Autoimmune hemolytic anemia (AIHA) has been associated with antiphospholipid antibodies (APLA). The aim of this study was to evaluate the presence of APLA and its possible correlation with diminished CD55 and CD59 in red blood cells from patients with primary AIHA or secondary to systemic lupus erythematosus (SLE). Flow cytometric analyses were performed on CD55 and CD59 stained erythrocytes from 24 patients (primary AIHA, n=8; AIHA plus SLE, n=11; and SLE without AIHA, n=5) and 20 healthy controls. Antibodies to several phospholipids were detected in the sera by ELISA. Most patients with AIHA plus SLE and few with primary AIHA showed deficiency of either or both CD55 and CD59 expression and was not associated to the presence of APLA, while SLE patients exhibited a normal expression of these molecules. Although our findings showed CD55 and CD59 deficiency in primary or secondary AIHA, it appears that this defect plays a facilitator rather than a triggering role for the hemolytic process. Additionally, a role of anti-phospholipid antibodies as causative of this acquired defect is questionable.