Chagas disease: a threat to safe blood transfusion

Chagas disease affects approximately 8 million infected people in Mexico and Central and South America and causes 12 500 deaths annually; 41 200 new cases are reported annually (2006). Coordinated multicenter programmes have decreased about 70% of new infections in South America due to the interruption of vectorial and decreased blood transfusion transmissions. Migration of the infected population from rural areas to urban centres in endemic and non-endemic countries led to the urbanization and globalization of Chagas disease. Chagas disease is now an emerging disease in non-endemic areas, where congenital, blood and organ transplant transmissions are associated with reactivation of chronic Chagas disease in patients under immunosuppression or HIV infection. Recent initiatives in non-endemic countries have been implemented to control its transmission by blood transfusion and transplants of organs. Most of the infected people were asymptomatic individuals in the chronic phase of the disease, characterized by and low and intermittent parasitemia and diagnosed by serological tests. In endemic countries, universal mandatory screening tests for detection of Trypanosoma cruzi antibodies dramatically reduced blood transfusion transmission. In non-endemic countries, where transfusion represents the most important way of transmission, different strategies have been registered: (1) blood donor selection and deferral; (2) blood donation testing; (3) blood donation testing in people who lived in endemic areas. Questionnaires containing well-defined questions help to identify patients from endemic areas and their epidemiological data but are of limited value since they depend on donor information. High-performance serologic tests were reported for the detection of anti-T. cruzi antibodies like ELISA with epimastigotes or trypomastigotes or recombinant antigens, chemiluminescent, immunoblot and radioimmunoprecipitation assays. Almost 100% of sensitivity and specificity were registered when tested in samples of well-defined chronic chagasic patients but gold standards are not validated in circumstances of low prevalence of the disease. Additionally, their value in cases of inconclusive results (one positive test and other negative or doubtful results) was not known. Unfortunately, molecular methods are less sensitive than serology for the chronic phase of the disease (45–100% sensitivity) and were not reliable for screening tests in blood banks. Perspectives of the reduction of parasites by photochemical treatment and ultraviolet (crystal violet, methylene blue, amotosalen, riboflavin, thiopirilium) were reported sometimes with slight changes in the blood products. However, the main challenge is to demonstrate their value for prevention of a broad spectrum of agents transmitted by blood transfusion (including príon disease) and inactivation of low parasite load. In summary, questionnaires including specific questions about donor epidemiology and high-performance serologic tests have been useful for blood bank screening. The cost–benefit–effectiveness analyses of universal serologic screening vs. serologic screening of selected donors depend on the prevalence of positive donors and should be evaluated in different regions. Finally, as pathogen inactivation methods may represent remarkable improvement in blood bank transfusion, efforts from the academia are necessary to prove their safety and effectiveness, and from blood banking–transfusion medicine community and public regulators to their implementation aiming to increase the safety of blood transfusion for patients around the world.     

Trypanosoma cruzi recombinant complement regulatory protein: a novel antigen for use in an enzyme-linked immunosorbent assay for diagnosis of Chagas' disease

Currently, diagnosis of Chagas' disease is based on serological methods, but due to the high occurrence of inconclusive results, more reliable methods are needed. The use of recombinant antigens for serodiagnosis of Chagas' disease is recommended in order to increase the sensitivity and specificity of the serological tests. The Trypanosoma cruzi complement regulatory protein (CRP) is a surface glycoprotein present on the trypomastigote forms of the parasite, and the recombinant CRP (rCRP) was cloned in a mammalian expression system and purified by affinity chromatography. The purified recombinant protein was used as an antigen in an enzyme-linked immunosorbent assay (rCRP ELISA) in order to verify its sensitivity and specificity compared with other established methods. In this evaluation, a panel of 184 serum samples distributed among chronic chagasic patients (n = 65), blood bank donors (n = 100), and patients infected with Leishmania spp. (n = 19) was used. The sensitivity and specificity of the rCRP ELISA were 100% when compared to conventional serology and complement-mediated lysis tests from these groups. When hemoculture and PCR tests were evaluated for diagnosis of chronic chagasic patients, using the rCRP ELISA as a reference test, the positivities were found to be 64.62 and 81.54%, respectively, showing a higher degree of sensitivity of the test. The data demonstrate that rCRP ELISA was able to discriminate between chronic chagasic patients and nonchagasic individuals, such as blood donors and patients with leishmaniasis. Thus, the rCRP is an excellent antigen for use in Chagas' disease diagnosis, due to the absence of false-negative or false-positive results.     

Serological confirmation of Chagas' disease by a recombinant and peptide antigen line immunoassay: INNO-LIA chagas

Although screening for Trypanosoma cruzi antibodies is mandatory in most South American countries, current tests are insensitive and have poor specificity. A recently optimized line immunoassay (the INNO-LIA Chagas assay) for the serological confirmation of Chagas' disease was evaluated at a large blood bank in S?o Paulo, Brazil. Sera from blood donors who reacted in at least one of three serological screening assays (n = 1,604) and who returned for a follow-up were retested, and the donors were interviewed to assess their epidemiological risk. The results obtained by the confirmatory assay evaluated in this study were compared to those obtained by the three different screening assays. Upon consideration of the consensus results obtained by the three different screening assays as a "gold standard," the INNO-LIA Chagas assay showed a sensitivity of 99.4% (95% confidence interval [CI], 98.3 to 99.9) and a specificity of 98.1% (95% CI, 96.6 to 99.0) for positive (n = 503) and negative (n = 577) sera. The INNO-LIA Chagas assay confirmed the results for significantly larger numbers of positive samples of at-risk individuals independent of the number of positive screening tests (P = 0.017, Mantel-Haenszel test). In conclusion, the INNO-LIA Chagas assay reliably confirmed the presence of antibodies to T. cruzi and can be implemented as a confirmatory assay for Chagas' disease serology.     

The clinical utility of anti-ribosomal P autoantibodies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease that can affect multiple organs and thus has a large spectrum of clinical presentations. Assessment of the autoantibody profile is fundamental for the clinical management of SLE patients, providing important data for diagnosis, clinical characterization and disease activity evaluation. Anti-ribosomal P protein (anti-Rib-P, anti-P) antibody, described in the 1980s, is a serological marker for SLE that is present in 13–20% of cases. This reactivity was initially thought to be associated with neuropsychiatric involvement in SLE, with certain conflicting results. Subsequently, associations of anti-Rib-P with liver and renal involvement in lupus were reported. Recently, anti-Rib-P was detected in autoimmune hepatitis patients. Anti-Rib-P reactivity to Trypanosoma cruzi ribosomal target antigens in patients with Chagas heart disease has also been described. This review focuses on the usefulness of the determination of anti-Rib-P in SLE and in other autoimmune and non-autoimmune disorders in clinical practice.     

Chagas disease in a rural area of Northeast Brazil

A serological and medical survey on Chagas disease was carried out between December 1997 and June 2000 in four villages of the semi-arid rural Northeast Brazil. The average human serological prevalence rate of 11.8% was strongly linked with age: 1.1% for people under 25, 13.7% for people aged of 26 to 49, 29.5% for people aged of 50+. The clinical form was indeterminate for 57% of the infected population, cardiac for 35%, digestive or mixed for 8%. The infected patients under 55 received at home an etiologic treatment with benznidazol. The survey confirms the drastic reduction of Trypanosoma cruzi transmission during the last decades, especially since 25 years. This situation is the result jointly of the antivectorial activities, improvement of education level and changes in the way of life. However Chagas disease is still a serious problem, especially for numerous middle-aged infected adults. The situation could be improved by increasing the serologic screening in the field as well as the counselling and the treatment of the patients.     

Cellular immunity during follow-up of patients with sarcoidosis of varying duration.

Cellular immunity was followed up at 3 month intervals for 1 year in 43 patients with sarcoidosis representing three well defined categories of the disease viz acute (12), subacute (20) and chronic (11). Twelve apparently healthy individuals served as controls. Each follow-up included the following tests: total number of blood lymphocytes, T cells, B cells, leucocyte migration tests with PPD, BCG and Kveim test material and stimulation tests of lymphocytes in vitro in the presence of PHA, Con A, PPD and PWM. Statistically, the most abnormal initial findings in all the tests were noted in acute sarcoidosis, followed by the subacute group. The acute group showed the most marked changes also during the follow-up. The smallest changes during the follow-up were seen in the patients with the chronic form of the disease. However, the inter-individual variation was considerable and no definite conclusions could be drawn from findings in a given case. Alterations in cellular immunity occur in sarcoidosis. They differ between different subgroups of patients and vary differently in course of time. Well defined criteria for inclusion of patients in an investigation and repeated studies of included patients will increase the information available from investigations of cellular immunity in sarcoidosis.     

Clinical and Molecular Analysis of 49 Patients With X-linked Agammaglobulinemia From A Single Center in Argentina

Introduction  Argentina has a large number of patients with definite diagnosis of X-linked agammaglobulinemia reported in the Latin-American registry. Forty-nine of them were seen in our referral pediatric hospital, between 1987 and 2005. Results and Discussion  A retrospective study of clinical, laboratory, and molecular data showed that respiratory tract infections were the most frequent initial clinical presentation and the most common among all manifestations prior to diagnosis (69%). Up to diagnosis, we found a high frequency of severe infections (sepsis, 14% and meningitis, 16%) and a high proportion of patients with chronic lung disease. During follow-up, the development of chronic lung disease was significantly related with age at diagnosis and inappropriate treatment. Conclusion  Although molecular diagnosis has been available in our center for the past 10 years, there is no doubt that awareness for early recognition of immunodeficiency should be improved through broader and more comprehensive education programs emphasizing characteristics of patients with immunodeficiencies. Natalia Basile and Silvia Danielian contributed equally to this work     

Sensitivity and Specificity of an Operon Immunochromatographic Test in Serum and Whole-Blood Samples for the Diagnosis of Trypanosoma cruzi Infection in Spain, an Area of Nonendemicity

Trypanosoma cruzi infection is an imported parasitic disease in Spain, and the majority of infected individuals are in the chronic phase of the disease. This study evaluated the sensitivity and specificity of the Operon immunochromatographic test (ICT-Operon; Simple Stick Chagas and Simple Chagas WB [whole blood]; Operon S.A., Spain) for different biological samples. Well-characterized serum samples were obtained from chagasic patients (n = 63), nonchagasic individuals (n = 95), visceral leishmaniasis patients (n = 38), and malaria patients (n = 55). Noncharacterized specimens were obtained from Latin American immigrants and individuals at risk with a clinical and/or epidemiological background: these specimens were recovered serum or plasma samples (n = 450), whole peripheral blood (n = 94), and capillary blood (n = 282). The concordance of the results by enzyme-linked immunosorbent assay and indirect immunofluorescence test was considered to be the "gold standard" for diagnosis. Serum and plasma samples were analyzed by Stick Chagas, and whole blood was analyzed by Simple Chagas WB. The sensitivity and specificity of the ICT-Operon in well-characterized samples were 100% and 97.9%, respectively. No cross-reactivity was found with samples obtained from visceral leishmaniasis patients. In contrast, a false-positive result was obtained in 27.3% of samples from malaria patients. The sensitivities of the rapid test in noncharacterized serum or plasma, peripheral blood, and capillary blood samples were 100%, 92.1%, and 86.4%, respectively, while the specificities were 91.6%, 93.6%, and 95% in each case. ICT-Operon showed variable sensitivity, depending on the kind of sample, performing better when serum or plasma samples were used. It could therefore be used for serological screening combined with any other conventional test.     

Retrospective study of severe cases of leptospirosis admitted in the intensive care unit

OBJECTIVES: Evaluate patient demographics, risk factors, complications, seropositivity, treatment and outcome among leptospirosis patients. DESIGN: Retrospective analysis of 104 patients admitted in the intensive care unit (ICU) with a clinical suspicion of leptopirosis. SETTING: Ten-bedded medical ICU in a medical school situated in a rural area endemic for leptospirosis. MAIN OUTCOME MEASURES: Seropositivity for leptospirosis, patient demographics, risk factors, complications, treatment and survival. RESULTS: One hundred and four patients were admitted with a clinical suspicion of leptospirosis. Fifty-three (50.7%) were serologically confirmed cases. Males dominated both groups. Most of the admissions were in the monsoon season. Exposure to moist soil was the main risk factor. The mortality in the seronegative group was 26.8% while it was only 3.8% in the seropositive group. Multi-organ dysfunction syndrome, primarily acute respiratory distress syndrome with thromboctyopenia and renal failure were the causes for mortality. All the patients who died presented late into the illness. CONCLUSIONS: The initial diagnosis of leptospirosis depends on a high index of clinical suspicion, routinely available diagnostic tests being unreliable in the initial period. A reliable, unsophisticated test should be developed for early detection of this disease. As leptospirosis in its early stage mimics other tropical infections, both medical professionals and the general public (especially with risk of occupational exposure) should be educated about the disease and the need to seek early medical intervention.     

Non-conventional flow cytometry approaches to detect anti-Trypanosoma cruzi immunoglobulin G in the clinical laboratory

We have recently developed a flow cytometric approach to detect anti-live trypomastigote and anti-fixed epimastigote IgG antibodies (FC-ALTA and FC-AFEA) in sera from individuals infected by Trypanosoma cruzi. Here, we present the first evaluation of the applicability of FC-AFEA-IgG as a diagnostic tool for Chagas disease. Performance analysis demonstrated that FC-AFEA-IgG has a sensitivity of 82% and a specificity of 100%. The assessment for prognosis performed by FC-ALTA-IgG1 and FC-AFEA-IgG, after classification of chagasic patients as belonging to indeterminate (IND), cardiac (CARD) or digestive (DIG) clinical forms, showed that most of IND have higher amounts of IgG than individuals' carrying CARD or DIG Chagas disease. FC-AFEA-IgG was also evaluated as a method to monitor chemotherapy efficacy in individuals classified into three distinct categories: not treated (NT), treated but not cured (TNC), and treated and cured (TC). Performance analysis demonstrated that FC-AFEA-IgG has an extraordinary capacity as a serological criterion to assess cure after therapeutic intervention in Chagas disease. These results represent a great advance in the application of serological techniques for clinical investigations on Chagas disease, and they clearly define new directions and perspectives. We intend to continue this field research focusing our attention on the influence of the degree of clinical damage on the FC-ALTA-IgG1 and FC-AFEA-IgG reactivity.     

Chlamydia pneumoniae serology: importance of methodology in patients with coronary heart disease and healthy individuals

Most publications on the relationship between infection with Chlamydia pneumoniae and coronary heart disease (CHD) propose an association, but negative studies are also reported. Seroepidemiological studies vary in the use of different serological methods, different cutoff limits, different sampling times in relation to acute cardiac events, and different clinical stages of CHD. We wanted to compare three different commercially available methods for measuring Chlamydia antibodies to see how the choice of method influenced the prevalence of seropositive individuals in CHD patients and in healthy individuals and to see if sampling time in relation to an acute cardiac event or the stage of atherothrombotic disease influenced the results. Blood samples from 197 CHD patients and 197 individually matched healthy control individuals were tested at baseline and after 6 months; the mean age was 55 years in both groups, and 18% were women. Among the CHD patients, 166 were included at a median of 16 days after an acute cardiac event and 31 had chronic disease with the latest acute event being >3 months earlier. The difference in prevalence of antibodies between the CHD patients and the healthy controls was significant when Chlamydia lipopolysaccharide antibodies were measured, while no significant differences between the study groups were observed by the two methods detecting Chlamydia pneumoniae major outer membrane protein antibodies. The number of seropositive individuals was quite similar at inclusion and 6 months later, and no significant differences were observed between patients with a recent cardiac event and those with a more remote cardiac event. We conclude that the choice of serological method is of major importance when evaluating a possible relationship between C. pneumoniae and CHD.     

Noninvasive tests in the initial evaluation of heart murmurs in children

We prospectively examined the usefulness of electrocardiography, chest radiography, and M-mode echocardiography in discriminating between the presence and absence of heart disease in 280 children older than one month and newly referred for evaluation of a heart murmur. After taking a history and performing a physical examination but before reviewing diagnostic tests, we categorized the children as having "no heart disease" (142), "possible heart disease" (34), or "definite heart disease" (104). Among the children initially thought to have no heart disease, the diagnosis was changed after a review of diagnostic tests in eight--three with mitral-valve prolapse, two with possible cardiomyopathy, and three with no heart disease on follow-up. Among those initially thought to have possible heart disease, the tests changed the diagnosis to definite heart disease in four, of whom only one had heart disease (mitral-valve prolapse) on follow-up. In no case did a review of tests change the diagnosis of definite heart disease. We conclude that the results of diagnostic tests are unlikely to change the clinical diagnosis of no heart disease or definite heart disease, when made by a qualified pediatric cardiologist in children newly referred for evaluation of a heart murmur.     

The use of IgG antibodies in conventional and non-conventional immunodiagnostic tests for early prognosis after treatment of Chagas disease

Treatment success of chronically infected Chagas disease patients is laborious and a positive prognosis often is made only after repetitive serological and/or parasitological examinations with continuous negative results. Recently, we have developed a non-conventional flow-cytometric method in order to detect immunoglobulin G antibodies against live trypomastigote forms of Trypanosoma cruzi and showed its usefulness in the prognosis of treatment success. In the present study, we investigated the performance of flow-cytometric anti-live trypomastigote IgG antibodies (FC-ALTA) and flow-cytometric anti-fixed epimastigote IgG antibodies (FC-AFEA), as well as conventional serological methods, for early monitoring of benznidazole treated Chagas disease patients, e.g. 5years after treatment. The analysis of individual FC-ALTA reactivity along the titration curve before and after treatment, we were able to show, that between 4% and 13% of treated patients under evaluation presented with reduced serological reactivity and segregated from the other patient groups. Similar results were obtained with semi-quantitative, conventional indirect hemagglutination or indirect immunofluorescence. Our data therefore suggest that the combined use of conventional and non-conventional serological methods could provide more suitable cure criteria in early post-therapeutic prognosis of Chagas disease.     

Comparative Evaluation of 11 Commercialized Rapid Diagnostic Tests for Detecting Trypanosoma cruzi Antibodies in Serum Banks in Areas of Endemicity and Nonendemicity

Chagas disease is one of the main public health issues in Latin America. Increasingly during the past few decades, Trypanosoma cruzi infection has been detected in North America, Europe, and the Western Pacific, mainly as a result of population movement. The limited availability of rapid serological diagnostic tests hinders rapid diagnosis and early treatment in areas of endemicity and nonendemicity. In collaboration with 11 national reference laboratories (NRLs) from different geographical areas, we evaluated the performances of commercialized serological rapid diagnostic tests (RDT) for T. cruzi infection. Eleven commercialized T. cruzi infection RDTs were evaluated on a total of 474 samples extensively tested with at least three different techniques for Chagas disease, maintained at controlled low temperatures, and stored in the serum banks of the 11 NRLs. We measured the sensitivity, specificity, and concordance of each RDT and provided an additional questionnaire to evaluate its ease of use. The selected RDTs in this study were performed under controlled laboratory conditions. Out of the 11 RDTs, we found 8 of them to be useful, with the cassette format favored over the strip. We did not observe significant differences in RDT performances in the different regions. Overall, the performance results were lower than those disclosed by the manufacturers. The results of this evaluation validate the possibility of using RDTs to diagnose Chagas disease, thereby decreasing the time to treatment at a primary health care facility for patients who are willing to be treated. Further studies should be conducted in the laboratory and in the field to confirm these data, expressly to evaluate reproducibility in resource-limited settings, or using whole blood in clinical settings in areas of endemicity and nonendemicity.     

Evaluation of a hypothetical protein for serodiagnosis and as a potential marker for post-treatment serological evaluation of tegumentary leishmaniasis patients

The serodiagnosis for tegumentary leishmaniasis (TL) presents problems related to the sensitivity and/or specificity of the tests. In the present study, an enzyme-linked immunosorbent assay (ELISA) technique was used to evaluate the performance from a Leishmania braziliensis hypothetical protein, LbHyM, in an attempt to compare its serological reactivity with a soluble Leishmania antigenic preparation (SLA) for the serodiagnosis of cutaneous (CL) and mucosal (ML) leishmaniasis. LbHyM was predicted to be a kinesin-like protein by bioinformatics tools. Serum samples were collected from both CL and ML patients, as well as from those with Chagas disease and from healthy subjects living in endemic or non-endemic areas of TL. Also, sera were collected from patients before and after the treatments, seeking to evaluate their serological follow-up in relation to the anti-protein and anti-parasite antibody levels. When an ELISA-rLbHyM assay was performed, it proved to be significantly more sensitive than ELISA-L. braziliensis SLA in detecting both CL and ML patients. Also, when using sera from Chagas disease patients, the ELISA-rLbHyM proved to be more specific than ELISA-SLA. The anti-protein and anti-parasite antibody levels were also evaluated 6 months after the treatments, and treated patients showed significantly lower levels of specific-rLbHyM antibodies, when compared to the anti-parasite antibody levels. In conclusion, the ELISA-rLbHyM assay can be considered a confirmatory serological technique for the serodiagnosis of L. braziliensis infection and can also be used in the serological follow-up of treated patients, aiming to correlate the low anti-protein antibody levels with the improvement of the healthy state of the patients.     

The clinical picture of chronic tick-borne encephalitis in children

According to data collected in Western Siberia over the past 20 years, tick-borne encephalitis (TBE) in 1.7% of patients becomes chronic. In the acute period, the disease in such cases usually progresses in the form of meningoencephalitis. This study concerns 44 clinical cases of chronic TBE in children of 5−14 years of age. All patients underwent comprehensive clinical and laboratory examination, and the diagnosis in each case was confirmed by serological tests. The hyperkinetic syndrome was the main manifestation of chronic TBE in 38 patients (86%). Among them, Kozhevnikoff's epilepsy was diagnosed in 35 patients (80%). The incidence of chronic TBE in Kemerovo region (the south of Western Siberia) remains unchanged, notwithstanding recent progress in its diagnosis and treatment. This emphasizes the necessity of more effective measures to prevent TBE and, in particular, large-scale vaccination of children living in the foci of this infection.     

Antibodies against a Leishmania infantum peroxiredoxin as a possible marker for diagnosis of visceral leishmaniasis and for monitoring the efficacy of treatment

Diagnosis of leishmaniasis is frequently based on serological methods, such as direct agglutination, immunofluorescence tests and ELISA assays with Leishmania total extracts, as antigen, however due to highly inconclusive results, more reliable tests are needed. In the present study, the prevalence of antibodies to a number of recombinant proteins (LmSIR2, LmS3a, LimTXNPx, LicTXNPx and LiTXN1) highly conserved among Leishmania species, were evaluated by ELISA in Leishmania infantum infected children from an endemic area of Portugal. We found that sera from children patients had antibodies against the different recombinant proteins, LicTXNPx presented the highest immuno-reactivity compared to the other and the most often recognized in the case of acute visceral leishmaniasis (VL). Moreover, in children treated with meglumine antimoniate or amphotericin B, antibodies against some of the recombinant proteins declined, whereas conventional serology using crude extracts showed little or no difference between the pre- and post-treatment values. The highest reduction was observed in the case of antibodies against the LicTXNPx protein. These results suggest that the antibodies against LicTXNPx might be a useful constituent of a defined serological test for the diagnosis and the monitoring of the therapeutic response in VL. The monitoring and follow-up in a large-scale field trials of such marker in areas where leishmaniasis is endemic will lend support to this.     

Interstitial pneumonia with autoimmune features: A single center prospective follow-up study

Background and objectiveRecently the term “interstitial pneumonia with autoimmune features” (IPAF) has been proposed to identify patients with interstitial lung disease and autoimmune characteristics, not fulfilling the criteria for specific connective tissue diseases (CTD). Only few data are available about the clinical and serological features of IPAF patients, their survival and the possible evolution in a CTD.The aims of the study were to investigate the demographic and clinico-serologic features of patients with IPAF, their relationship to survival, and the possible evolution in a definite CTD.Patients and methodsFifty-two patients were consecutively enrolled and prospectively followed for 45 ± 31.6 months. Data about disease onset, serological, clinical and therapeutic features, pulmonary function tests and high-resolution computed tomography were periodically repeated. The survival of patients with IPAF was compared with that of 104 patients with idiopathic pulmonary fibrosis (IPF).ResultsThe clinical domain for IPAF was satisfied in 44 patients, serological domain in 49 and the morphological domain in 29 patients. During the follow-up, a definite CTD was diagnosed in 7 patients, in particular Sjogren's syndrome in 4 patients, rheumatoid arthritis in 2, and polymyositis in the last.The estimated 5-year survival of IPAF patients 69.5 ± 7.8%, significantly higher than survival observed in IPF patients, and the baseline value of FVC and DLCO were the only factors associated to death.ConclusionsIPAF seems to a distinct entity, with a low tendency to evolve in a definite CTD. Nevertheless, further studies are needed to better define the clinical evolution and the outcome of IPAF.     

Indeterminate colitis

Indeterminate colitis (IC) originally referred to those 10-15% of cases of inflammatory bowel disease (IBD) in which there was difficulty distinguishing between ulcerative colitis (UC) and Crohn's disease (CD) in the colectomy specimen. However, IC is increasingly used when a definitive diagnosis of UC or CD cannot be made at colonoscopy, in colonic biopsies or at colectomy. The diagnostic difficulties may explain the variably reported prevalence of IC. Clinically, most patients with IC evolve to a definite diagnosis of UC or CD on follow up. The role of ancillary tests in the distinction of UC from CD is reviewed. The low sensitivity of serological markers limits their usefulness. Other tests include upper endoscopy and magnetic resonance imaging. The definition of IC may not be a purely histological one derived from resected specimens, but rather a clinicopathological one. This review offers some personal observations and viewpoints, and proposes an approach to some of the relatively more esoteric combinations of findings.