LN Vida

BACKGROUND: There is no information about the frequency of liver dysfunction in patients with inflammatory bowel disease (IBD) treated with immunosuppressants and infected with hepatitis B (HBV) and/or C virus (HCV). AIM: To assess the influence of immunosuppressants on the course of HBV and HCV infection in IBD. METHODS: Patients with IBD with HBV and/or HCV infection from 19 Spanish hospitals were included. Clinical records were reviewed for the type of immunosuppressant used, treatment duration, liver function tests and viral markers before, during and after each immunosuppressant. Logistic and Cox regression analysis were used to identify predictors of outcome. RESULTS: 162 patients were included; 104 had HBV markers (25 HBsAg positive) and 74 had HCV markers (51 HCV-RNA positive), and 16 patients had markers of both infections. Liver dysfunction was observed in 9 of 25 HBsAg positive patients (36%), 6 of whom developed hepatic failure. Liver dysfunction in HCV was observed in 8 of 51 HCV-RNA positive patients (15.7%), and only one developed hepatic failure. The frequency and severity of liver dysfunction was significantly higher in HBV-infected patients than in HCV-infected patients (p=0.045 and p=0.049, respectively). Treatment with ≥2 immunosuppressants was an independent predictor of HBV reactivation (OR 8.75; 95% CI 1.16 to 65.66). The majority of patients without reactivation received only one immunosuppressant for a short period and/or prophylactic antiviral treatment. No definite HBV reactivations were found in anti-HBc positive patients lacking HBsAg. CONCLUSION: Liver dysfunction in patients with IBD treated with immunosuppressants is more frequent and severe in those with HBV than in HCV carriers and is associated with combined immunosuppression.

A new hematologic syndrome with phenotypic features of mild Hb H disease was identified in three children from two unrelated black American families. Erythrocytes from each of these children contained Hb H (beta 4) and Hb Barts (gamma 4), as well as a slowly migrating hemoglobin fraction that made up 7-10% of the total hemoglobin. The parents of the affected children all showed mild thalassemia-like changes, with one of the parents in each family also expressing the variant hemoglobin; in the latter individuals the mutant alpha-chains made up less than 2% of the total, and were present mainly or exclusively in combination with delta-chains in the form of a slowly migrating Hb A2. Purified Hb Evanston showed an increased oxygen affinity, but its Bohr effect, cooperativity, and 2,3-diphosphoglycerate effect were normal. The mutant hemoglobin appeared to have normal stability to heat and to isopropanol, and the stability of its alpha-chain in an extended time course synthesis study also appeared to be similar to that of alpha A. However, the results from short-term globin synthesis studies, and from mRNA translation in vitro, suggest that the two types of alpha-chains were synthesized at relatively equal rates, with a major fraction of the newly synthesized variant alpha-chains undergoing rapid catabolism. The hematologic data taken in combination with DNA hybridization and globin synthesis findings indicate that the proposita in each of these families has the genotype--, alpha A/--, alpha Ev. These observations suggest that two separate mechanisms are contributing to the alpha-thalassemia-like expression of Hb Evanston : the newly synthesized alpha EV-chains are unstable and are subject to early proteolytic destruction; and the mutant alpha-allele is linked to an alpha-globin gene deletion.

An electrophoretically slow-moving hemoglobin variant was identified in three members of a family originating from Southern Mexico. The variant, Hb Lincoln Park, made up approximately 14% of the total hemoglobin and appeared to have normal stability and functional properties. None of the individuals in whom the abnormal hemoglobin was present was anemic, but each had a mildly elevated reticulocyte count. Structural data suggest that the non-alpha chain of Hb Lincoln Park represents a betadelta gene-fusion product, with normal beta chain structure of the amino-terminal portion of the chain and delta sequences subsequently, the crossover point occurring between animo acid residues 22 and 50. An additional abnormality is the deletion of valine-137, a component of the delta gene-derived segment of the betadelta chain. To account for the development of this abnormal globin chain, a series of intergenic crossovers is proposed; the first, a nonhomologous crossover between the beta and delta genes, presumably gave rise to the betadelta fusion gene; two additional crossovers, one of them unequal, may then have occurred between the same beta and delta genes to produce the amino acid deletion.

In Hb Warsaw Val replaces the Phe normally present at the heme contact position beta 42 (CD1). This variant is unstable, and it readily undergoes methemoglobin formation. In DEAE-cellulose chromatography, the variant hemoglobin co-eluted with Hb A; a partially heme-depleted fraction of the variant, representing 5-6% of the total hemoglobin, eluted separately and in pure form. The heme replete form of Hb Warsaw exhibited decreased oxygen affinity with a normal Bohr effect and normal cooperativity and interaction with 2,3-diphosphoglycerate (DPG). The heme-depleted Hb Warsaw had a higher oxygen affinity than that of Hb A, decreased cooperativity and 2,3-DPG interaction, and a very low alkaline Bohr effect. Gel filtration of the heme-depleted form showed it to exist entirely as alpha beta dimers. Globin chain synthesis by Hb Warsaw-containing reticulocytes followed a balanced alpha/beta ratio. In short-term synthesis experiments, a major portion of incorporated radiolabeled L-leucine was recovered from the dimeric, heme-depleted Hb Warsaw fraction, suggesting that subunit association precedes the incorporation of heme into the beta subunits in the post-synthetic assembly of this hemoglobin. Structural analysis of deoxyhemoglobin containing roughly equal proportions of normal and variant beta chains showed that the replacement leaves a cavity next to the heme that is large enough to hold a water molecule, which may account for the instability of Hb Warsaw. The heme and the pyrrol nearest to ValCD1 tilt into the cavity. The resulting increase in the tilt of the proximal histidine relative to the heme plane, coupled with a possible stretching of the Fe-N epsilon bond may account for the low oxygen affinity.

Hb Mizuho [beta 68(E12)Leu----Pro] was identified in a child of Italian/Sicilian descent who exhibited severe, transfusion dependent hemolytic anemia which improved following splenectomy. The patient's peripheral blood smear, which prior to splenectomy demonstrated coarse erythrocytic basophilic stippling, showed large, dense erythrocytic hemoglobin inclusions following splenectomy. Whole blood oxygen equilibrium results were consistent with the presence of a hemoglobin component exhibiting increased oxygen affinity with decreased cooperativity. The abnormal beta chain was characterized by high performance liquid chromatography analysis of the isopropanol precipitable hemoglobin fraction.