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Antibodies to actin in autoimmune haemolytic anaemia.

ABSTRACT: BACKGROUND: In autoimmune haemolytic anaemia (AIHA), autoreactive antibodies directed against red blood cells are up-regulated, leading to erythrocyte death. Mycoplasma suis infections in pigs induce AIHA of both the warm and cold types. The aim of this study was to identify the target autoantigens of warm autoreactive IgG antibodies. Sera from experimentally M. suis-infected pigs were screened for autoreactivity. RESULTS: Actin-reactive antibodies were found in the sera of 95% of all animals tested. The reactivity was species-specific, i.e. reactivity with porcine actin was significantly higher than with rabbit actin. Sera of animals previously immunised with the M. suis adhesion protein MSG1 showed reactivity with actin prior to infection with M. suis indicating that molecular mimicry is involved in the specific autoreactive mechanism. A potentially cross-reactive epitope was detected. CONCLUSIONS: This is the first report of autoreactive anti-actin antibodies involved in the pathogenesis of autoimmune haemolytic anaemia.

SUBMITTER: Felder KM

PROVIDER: S-EPMC3003239 | biostudies-literature | 2010

REPOSITORIES: biostudies-literature

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Antibodies to actin in autoimmune haemolytic anaemia.

Felder Kathrin M KM Hoelzle Katharina K Heinritzi Karl K Ritzmann Mathias M Hoelzle Ludwig E LE

BMC veterinary research 20100330

<h4>Background</h4>In autoimmune haemolytic anaemia (AIHA), autoreactive antibodies directed against red blood cells are up-regulated, leading to erythrocyte death. Mycoplasma suis infections in pigs induce AIHA of both the warm and cold types. The aim of this study was to identify the target autoantigens of warm autoreactive IgG antibodies. Sera from experimentally M. suis-infected pigs were screened for autoreactivity.<h4>Results</h4>Actin-reactive antibodies were found in the sera of 95% of a ...[more]

PMID: 20353574

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Project description:BACKGROUND: Parenteral artesunate is recommended as first-line therapy for severe and complicated malaria. Although its efficacy has been proven, long-term safety profile is still under evaluation. Several cases of delayed haemolytic anaemia occurred after initial clinical improvement and resolution of parasitaemia in non-immune travellers and children living in endemic areas. Reports have generated concern that this phenomenon might be related to the treatment itself, either by direct toxicity or immune-related mechanism. This is a report of the first case of autoimmune haemolytic anaemia following treatment of severe malaria initially managed with parenteral artesunate with strong indication for drug-immune related mechanism. CASE: A 17-year old Ivoirian female travelling in France presented with fever, headache and abdominal pain seven days after her arrival. Physical examination was indicative of septic shock while blood analysis showed normal haemoglobin level, but profound thrombocytopaenia and hyperlactataemia. Blood smear analysis showed Plasmodium falciparum infection with a parasitaemia of 0.8%. Severe malaria was diagnosed according to the WHO criteria. The patient was initially managed with artemether/lumefantrine combination and then parenteral artesunate for 48 hours. Empiric antibiotic course was also initiated with ceftriaxone, metronidazole, gentamycin, and then piperacillin and ciprofloxacin. At day 14, haemoglobin dropped to 4.6 g/dL with biologic features indicative of haemolysis (LDH 658 U/L, haptoglobin<0.15 g/L). At that time, parasitaemia was negative and other infections or hereditary disorders were excluded, while Coombs' direct antiglobulin test was positive for IgG and C3d. Antinuclear antibodies were absent. Further investigations evidenced drug-induced antibodies related to artesunate. It was concluded a drug-mediated autoimmune haemolytic anaemia. A corticosteroids regimen was initiated at 1 mg/kg/day. Outcome was favourable and corticosteroids were progressively tapered during two months. At present the patient's condition remains stable without recurrence of haemolytic anaemia. CONCLUSION: This is the first case of delayed haemolytic anaemia related to artesunate with a strong indication for drug-immune related mechanism. Further research is warranted to better characterize this plausible cause of post-treatment haemolysis following parenteral artesunate administration in severe malaria patients.

Project description:BackgroundSevere autoimmune haemolytic anaemia (AIHA) in systemic lupus erythematosus (SLE) patients could be life-threatening and formidable, especially in those nonresponsive to glucocorticoids (GCs) and immunosuppressants (ISAs). Whole-blood exchange transfusion (WBE), with plasma exchange and pathogenic cell removal as well as healthy red blood cell transfusion, could be beneficial. The objective of this study was to investigate the efficacy and safety of WBE in combination with GCs/ISAs.MethodsIn this retrospective study, the clinical data of 22 refractory severe SLE-AIHA inpatients between February 2016 and February 2021 were collected and analysed, among whom 14 patients had received WBE and were compared with those treated with typical second-line therapy of intravenous immunoglobulin and/or rituximab (IVIG/RTX).ResultsAmong the 22 severe refractory SLE-AIHA patients, eight patients received IVIG and/or RTX without WBE (group 1, IVIG/RTX, n = 8), seven patients were given WBE without IVIG/RTX (group 2, WBE alone, n = 7), and seven patients who failed initial IVIG/RTX therapy were given sequential WBE therapy (group 3 IVIG/RTX→WBE, n = 7). Fourteen patients had accepted WBE treatment regardless of prior IVIG/RTX usage (group 2 + 3, WBE ± IVIG/RTX, n = 14). On days 1, 3, 5, and 7 after corresponding therapies, patients of groups 2, 3, and 2 + 3 showed significantly higher levels of haemoglobin (Hb) than patients of group 1. Compared with patients of group 1, patients of groups 2, 3, and 2 + 3 took less time to reach and maintain Hb ≥60 g/L from baseline. Groups 2 and 2 + 3 consumed a lower dose of GCs than group 1 to reach and maintain Hb ≥60 g/L from baseline. Group 1 experienced longer hospital stays than group 2, and group 3's cost of hospitalisation is more than groups 1 and 2. Hbmin <40 g/L may be a key indicative factor for initiating WBE remedy therapy as IVIG/RTX may not be effective enough in 48-72 h in those patients with refractory severe SLE-AIHA. No severe adverse effects were observed in the WBE group.ConclusionsWBE could be a safe and beneficial alternative therapy for refractory severe SLE-AIHA.

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Antibodies to actin in autoimmune haemolytic anaemia.

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Antibodies to actin in autoimmune haemolytic anaemia.

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