T-CELL RECOGNITION OF HEPATITIS-B ENVELOPE PROTEINS

We have studied the T-cell processing pathways of Hepatitis B antigens and the role of specific B lymphocytes. It could be shown that some form of processing by specific B cells is required for class I CTLs. This mechanism differs from class II endosomal processing. In addition, it could be shown that lysis of HBsAg-specific B cells may be partly responsible for chronic HBV carrier states

CYCLOSPORINE-A IN THE TREATMENT OF AUTOIMMUNE CHRONIC ACTIVE HEPATITIS OCCURRING WITH OR WITHOUT CIRCULATING ANTIBODIES AGAINST HEPATITIS-C VIRUS

The aim of this study was to evaluate the efficacy of cyclosporin A (CyA) in the treatment of autoimmune chronic active hepatitis (CAH) occurring either with or without circulating anti-hepatitis C virus (HCV) antibodies. The study population consisted of eleven patients with histological finding of CAH associated with high titres of anti-nuclear antibodies and hypergammaglobulinaemia. Eight patients were found to be also positive for circulating antibodies against hepatitis C virus (HCV). CyA was administered orally for 1 year at a dose of 5 mg/kg/die. The results demonstrate that CyA is effective in inducing a persistent biochemical and histological improvement in those patients negative for anti-HCV antibodies. On the other hand, in only one anti-HCV-positive patient was a sustained decrease of ALT level observed, and no histological change was found at the end of treatment in any of the anti-HCV-positive patients. These results suggest that CyA therapy might be indicated only for those autoimmune CAH patients without evidence of HCV infection

INCIDENCE OF ANTI-WRA DETECTION USING WR(A+) ANTIBODY SCREENING CELLS IN PRE-TRANSFUSION TESTING

Background and Objectives Antibodies to low incidence RBC antigens are not rare in candidates to blood transfusion, though the risk of receiving a non-compatible unit is low. Sometimes commercial RBC sets for the screening of irregular antibodies contain Wr(a+) cells: but these cells increase the workload of antibody characterization due to the presence of anti-Wra in recipients. Materials and Methods We have studied both the incidence of Wra antibodies and the effects on routine work of having a Wr(a+) cell in the screening test in an unselected population of 787 patients requiring RBC transfusion and in 151 new blood donors. Results Irregular antibodies were found in 64 sera, 58 of which were specific for Wra , 46 (5,8%) and 12 (7,9%) among patients and donors, respectively. All the positive tested sera contained specific IgM, whereas IgG were also found in 71% of the cases. The use of an antibody screening RBC set, including a Wr(a+) cell, increased the efforts towards the definition of the irregular Abs in the positive screened samples, by three times compared to the previous period. Conclusion A specific anti- Wra IgM component has always been found in positive sera. This component can easily be detected during cross- match procedures. Moreover, the association between anti-Wra and haemolytic transfusion reaction is rare. Therefore, the inclusion of Wr(a+) cells in pre-transfusion screening of blood recipients is not justified by clinical relevance and it causes an undue increase in costs and time to unit release

ANEMIA EMOLITICA AUTOIMMUNE E GRAVIDANZA

ANEMIA EMOLITICA AUTOIMMUNE E GRAVIDANZA Coluzzi S.(1), Giovannetti G.(1), La Rocca U.(1), Neri A.(1), Santilio I.(1), Girelli G.(1), Arista M.C.(1) (1)UOC Immunoematologia e Medicina Trasfusionale, Azienda Ospedaliero-Universitaria Policlinico Umberto I, Roma Premessa. La malattia emolitica autoimmune (MEA) è una condizione acquisita rara causata da anticorpi (Ac) rivolti verso antigeni self eritrocitari. La presenza di autoimmunizzazione eritrocitaria pre-esistente o l'insorgenza durante la gravidanza sono oggetto di attento monitoraggio immunoematologico, in particolare nei casi in cui l'autoAc sia di classe IgG, pertanto in grado di superare la barriera placentare e potenzialmente causare sensibilizzazione degli eritrociti fetali. Metodi. Sono state revisionate le schede del workup immunoematologico di donne in gravidanza pervenute in un anno nel nostro ambulatorio per il monitoraggio finalizzato alla prevenzione della malattia emolitica feto-neonatale (MEFN); nella maggior parte dei casi si trattava di donne con ricerca Ac risultata positiva presso altri laboratori. In accordo con quanto previsto dalle Raccomandazioni SIMTI-SIGO, è stata effettuata una determinazione del fenotipo ABO/Rh/K nel I trimestre di gravidanza, confermata a 28 settimane di gestazione, e la ricerca di Ac eritrocitari irregolari. In caso di risultato positivo, lo studio includeva: test dell'antiglobulina diretto (TAD), caratterizzazione della classe Ig dell'autoAc ed identificazione di eventuali alloAC, titolazione Ac(auto/ alloAc), come parte del check-up finalizzato all'inquadramento di un'eventuale insorgenza di MEFN e nell'eventualità di una richiesta trasfusionale nella madre e/o nel figlio. Il monitoraggio immunoematologico è stato condotto, in relazione ai risultati ottenuti, secondo quanto previsto dalle Raccomandazioni. Risultati. Nel corso di un anno sono stati effettuati 375 studi immunoematologici in 124 donne in gravidanza. Di queste, in 10 lo studio dava esito negativo, in 3 era evidenziata interferenza dovuta ad Ac verso mezzi potenzianti/conservanti dei pannelli eritrocitari, mentre in 111 lo studio risultava positivo per la presenza di auto o alloAc; in 10/111 pazienti (9%) veniva diagnosticata una MEA (8 da Ac di tipo caldo IgG, 1 di tipo freddo IgM, 1 di tipo misto IgG+IgM). In4/10 pazienti si associavano alloAc (4 casi anti-Wra, 1 anti-Wra+anti-E (titolo1), 1 anti-C (indosabile); il titolo dell'autoAc IgG era<16 in tutti i casi. In 3/10 neonati da madri con autoimmunizzazione eritrocitaria, il TAD alla nascita era risultato positivo, di tipo IgG, e si eluiva l'Ac privo di specificità convenzionali, di provenienza materna; nessuno dei tre neonati con TAD positivo aveva presentato anemia e/o iperbilirubinemia alla nascita e al controllo a 1 mese. Conclusioni Nella nostra esperienza il riscontro di autoAc materni non ha comportato alcuna conseguenza nel feto/ neonato; tuttavia in tutti i casi il titolo degli autoAc era modesto, anche nei casi in cui era stato necessario instaurare terapia steroidea nella madre a causa della significatività clinica dell'autoAc. Seppur anche in letteratura sia riportata una bassa percentuale di neonati con segni di emolisi causati da autoAc materni, cionondimeno è raccomandato un atteggiamento di attenta sorveglianza, al fine di instaurare un pronto trattamento nella madre, soprattutto nei casi in cui si associ un più ampio disordine dell'immunità, e per evidenziare alloAc che, eventualmente presenti e più pericolosi per il feto, potrebbero essere mascherati dall'autoAc

NORMALIZATION OF DEPRESSED NATURAL-KILLER ACTIVITY AFTER INTERFERON-ALPHA THERAPY IS ASSOCIATED WITH A LOW-FREQUENCY OF RELAPSE IN PATIENTS WITH CHRONIC HEPATITIS-C

In the present study, we found that human recombinant interferon-alpha(rIFN-alpha) given at a dose of 3 x 10(6) units thrice weekly for three months, and 1,5 x 106 units thrice weekly for the next three months, was able to restore depressed natural-killer (NK) activity to normal values in 12 out of 21 chronic hepatitis C patients positive for anti-HCV antibodies. In all of these patients, NK normalization was still sustained after three months from suspension of therapy. Eighteen patients also showed a normalization of the alanine aminotransferase (ALT) level by the end of treatment (responder patients), independently of changes in NK activity. No significant improvement in either NK activity or aminotransferase levels was seen among 20 untreated patients. In 8 responder patients (1 with normalized and 7 with low NK activity), ALT levels returned to pre-therapy values within three months after suspension of r/FN-alpha administration (relapse). We found that patients who normalized NK activity had a lower frequency of relapse as compared to patients with low NK activity by the end of treatment (p > 0.01). Immunofluorescence analysis of biopsy-derived liver tissue revealed that r/FN-alpha was able to induce strong MHC class I antigen expression on hepatocytes of treated patients, but this was not related to the clinical course

Selective expansion of cytotoxic T lymphocytes with a CD4+CD56+ surface phenotype and a T helper type 1 profile of cytokine secretion in the liver of patients chronically infected with hepatitis B virus

Highly purified CD4+ T cells isolated from liver biopsies of patients with hepatitis B virus-induced CAH had a strong cytotoxic activity and were comprised of a substantial number of cells (25%-40%) expressing CD56 surface marker. These cells were absent in CD4+ T cells from the peripheral blood of CAH patients or normal controls and these suspensions did not have cytotoxic activity. CD4+CD56+ T cells were further characterized by studies at the clonal level. A total of 71 hepatitis B envelope antigen-specific CD4+ T cell clones was investigated (23 from liver biopsies, 48 from peripheral blood of patients or normal vaccinated individuals). A total of 16 out of 23 (69.5%) of the clones from liver biopsies, but only 4.1% (2 out of 48) of those from PBLs, expressed CD56. A clone was defined as CD56+ when 40% or more of the cells expressed the marker. Production of TNF-α, IL-4, IL-5, IL-2, and IFN-γ was investigated in 15 CD4+CD56+ and in 18 CD4+CD56- T cell clones, which shared the same HLA restriction element (DR2w15) and the same fine specificity (peptide 193-207 of the S region). All of the clones from the two groups released TNF-α and IL-2. However, all of the CD4+CD56+ T cell clones produced IFN-γ but not IL-4 and IL-5 (Th1-like cell clones). Fourteen of the CD4+CD56- clones released IFN-γ, IL-4, and IL-5 (Th0-like cell clones); three produced IL-4 and IL-5 but not IFN-γ (Th2-like cell clones); and only one had a Th1 cytokine secretion profile. Cell fractionating studies within single CD4+CD56+ T cell clones showed that cells expressing high density CD56 had a stronger cytotoxic activity and produced higher levels of IFN-γ than cells with low density CD56, thus further supporting a correlation between CD56 expression and cell functions. The results indicate that: 1) in CAH patients, cytotoxic CD4+ T cells with a Th1 cytokine secretion profile are compartmentalized in the liver, 2) these cells may be identified by the expression of CD56, 3) the expansion of these cells may be facilitated by antigenic stimulation within the inflammatory environment of the liver, and 4) CD4+CD56+ cells may play a pathogenetic role in hepatitis B virus infection