Evaluation of the LIAISON ANA Screen Assay for Antinuclear Antibody Testing in Autoimmune Diseases

Antinuclear antibodies (ANA) are widely detected by immunofluorescence on HEp-2 cells in patients with connective tissue diseases and other pathological conditions. We evaluated the first-automated chemiluminescence immunoassay for the detection of ANA (LIAISON ANA screen, DiaSorin). This study was carried out simultaneously in two laboratories by testing 327 patient samples with clinically defined connective diseases, 273 routine samples for ANA screening, and 300 blood donors. A total of 268 out of 337 IIF-positive sera were positive with LIAISON ANA screen (79.5% of agreement) and 240 out of 263 IIF-negative sera were negative with LIAISON ANA screen (91.2% of agreement). After resolution of discrepant results, the concordance reached, respectively, 94.9% and 98.8%. The specificity was 99.3% and the sensitivity was 94%. Unlike results obtained by other ANA screening assays, we observed acceptable sensitivity and specificity. Despite the presence of HEp-2 cell extract, we failed to detect some antibodies as antinucleolar, antinuclear envelope, and antiproliferating cell nuclear antigen. This automated assay allows quick process to results and exhibits satisfactory sensitivity for the detection of the main ANA specificities of connective tissue diseases.

[Antimalarial drug resistance]

Drug resistant malaria is mostly due to Plasmodium falciparum, the highly prevalent species in tropical Africa, Amazon, and Southeast Asia. P. falciparum is responsible for severe involvement of fever or anemia causing more than a million deaths per year. Rationale for treatment is becoming weak as multiple drug resistance against well-tolerated drugs develops. P. falciparum drug resistant malaria originates from chromosomal mutations. Analyses using molecular, genetic and biochemical approaches showed that: 1) impaired uptake of chloroquine by the parasite vacuole is a common characteristic of resistant strains, this phenotype correlates with pfmdr1 and pfcrt gene mutations; 2) one S108N to four (N51I, C59R, I164L) point mutations of dihydrofolate reductase, the enzyme target of antifolinics (pyrimethamine and proguanil), give moderate to high level of resistance to these drugs; 3) resistance to sulfonamides and sulfones involves mutations of dihydropteroate synthase (A437G, K540E), their enzyme target, impairing their capacity to potentiate antifolinic drugs; 4) resistance to atovaquone plus proguanil involves one single mutation on atovaquone target, cytochrome b (Y268S, C or N); 5) resistance to mefloquine is thought to be linked to the over expression of pfmdr1, a pump expelling toxic waste from eukaryotic cells. P. falciparum resistance levels may differ according to places and time, depending on malaria transmission and drug pressure. Coupling in vivo to in vitro tests, and using molecular tests is essential for the surveillance of replacement drugs. Low cost biochemical tools are urgently needed for a prospective monitoring of resistance.

[Analysis of nine autoantibodies associated with systemic autoimmune diseases using the Luminex technology. Results of a multicenter study]

Luminex technology allows simultaneous detection of several analytes in a single well. Applications have been recently developed for the detection of autoantibodies.

PURPOSE

To evaluate the performances and convenience of the Fidis analytical system (BioMedical Diagnostics, Marnes-la-Vallee, France) for the detection of nine autoantibodies associated with connective diseases: SS-A, SS-B, Sm, RNP, Scl-70, Jo-1, CENP-B, P ribosomal and double stranded DNA antibodies.

MATERIALS AND METHODS

Three hospital laboratories analysed 366 samples taken from their serum banks and corresponding to the main systemic autoimmune diseases. Control samples included 120 sera from blood donors and 42 sera from patients with dysglobulinemia.

RESULTS

In each laboratory, handling of this new analytical system was easy. Results are readily obtained: nine autoantibodies are quantitated in fourty-four sera in less than two hours. A clear-cut discrimination between negative and positive results was observed, due to very low backgrounds. Intra-assay and inter-assay variations were low: coefficients of variation were under 10% in 80 and 64% of the cases, respectively. Results obtained with Fidis correlated satisfactorily with those obtained with the numerous routine techniques used in each laboratory. The overall concordance exceeded 93%.

CONCLUSION

Fidis is a reliable and time-saving analytical system for the detection of autoantibodies associated with systemic autoimmune diseases.

Questions about dexamethasone use for the prevention of anti-SSA related congenital heart block

BACKGROUND

Mothers with anti-SSA/Ro antibodies who have had a previous fetus with congenital heart block (CHB) have a risk of recurrence estimated to be up to 16%.

OBJECTIVE

To improve the management of these "high risk patients" by determining (a) whether or not prophylactic treatment is efficient; (b) whether or not fluorinated steroids (betametasone and dexamethasone) that do cross the placenta in an active form are safe for the fetus; and (c) which prophylactic treatment should be used.

METHODS

Retrospective study performed on seven mothers sent to a university hospital owing to a past history of one (six mothers) or two children (one mother) with CHB.

RESULTS

13 subsequent pregnancies occurred. No CHB was observed. All four pregnancies in women treated with 10 mg/day prednisone were uneventful. Three pregnancies in women receiving no steroids resulted in two early spontaneous abortions and one live birth. The six pregnancies in women treated with dexamethasone (4-5 mg/day) ended in one early and one late spontaneous abortion, two stillbirths, and two live births with intrauterine growth restriction and mild adrenal insufficiency. A histological study of one stillbirth disclosed intrauterine growth restriction and marked adrenal hypoplasia.

CONCLUSION

Adverse obstetric outcomes were often seen here and major concerns have been raised by paediatricians about the safety of fluorinated steroids, owing to the results of animals studies, retrospective data, and randomised trials. Because fluorinated steroids have not been shown to improve prophylactic treatment of CHB in pregnant women at high risk, their use is questionable.

[Neurological manifestations in cryoglobulinemia]

Cryoglobulins are immunoglobulins that persist in the serum, precipitate at cold temperature and resolubilize when rewarmed. Type I is often associated with hematological disorders. Type II and III are mixed cryoglobulins, composed of different immunoglobulins with a monoclonal component in type II and only polyclonal immunoglobulins in type III. Mixed cryoglobulins are associated with connective tissues or infectious diseases. Hepatitis C virus is involved in most of previously called "essential" mixed cryoglobulinemia. Dermatological, rhumatological, and nephrological manifestations are the most frequent, and neurological complications are found in 20 percent of cases. However, in mixed cryoglobulinemia with low cryoglobulins level, neurological signs may reveal the disease. Ischemic central nervous system complications are rare, but sensory, axonal, peripheral neuropathies or sensory and motor multiple mononeuropathies are more frequent. Prognostic and treatment depend on association with hepatitis C, and presence of vasculitis lesions in the nerve biopsy.

Effect of cryoglobulin and crystalcryoglobulin on TNF-alpha production by normal human monocytes

OBJECTIVES

We recovered an IgG1-kappa cryocrystalglobulin in synovial fluid and membrane specimens from a patient with destructive arthropathy. In the present study, we investigated its proinflammatory properties by measuring its effects on TNF-alpha production by normal human monocytes.

MATERIALS AND METHODS

Normal human monocytes isolated by plastic adhesion were cultured in microtiter plates. Adherent monocytes were cultured for 6, 8, and 24 hours with sterile cryocrystalglobulin (150 microg/mL and 2 mg/mL), type I noncrystallised cryoglobulin (same concentrations), monosodium urate (MSU) crystals (2 mg/mL), LPS (10 microg/mL), or medium alone. Supernatant TNF-a concentrations were assayed using an ELISA.

RESULTS

Cryocrystalglobulin had no effect on TNF-alpha production by normal human monocytes. Noncrystallised cryoglobulin increased TNF-alpha levels in supernatants in a time-dependent and concentration-dependent fashion. This increase was significantly less marked than the increases achieved with MSU crystals or LPS.

CONCLUSION

IgG1kappa cryocrystalglobulin has no effect on TNF-alpha production by normal human monocytes. Fc region changes within the cryocrystalglobulin molecule may explain this finding.

Mixed cryoglobulinemia and hepatitis C virus infection

The striking association between hepatitis C virus (HCV) infection and mixed cryoglobulinemia (MC) has conducted to the hypothesis that HCV plays a major role in the production of MC. MC is a systemic vasculitis characterized by the presence in the serum of cryoprecipitable immunoglobulins (Ig), with rheumatoid factor (RF) activity. HCV which is both a hepatotropic and lymphotropic virus, has been proposed as a causative agent of MC, and is responsible for clinic manifestations such as glomerulonephritis, vasculitis, neuropathy. Because MC evolves frequently into B-cell non-Hodgkin lymphoma (NHL), chronic HCV infection has been proposed as an aetiologic factor in B-cell lymphoma. Several controlled trials have demonstrated that combined therapy with interferon and ribavirin is beneficial in chronic hepatitis C with and without MC. Several studies have also suggested that interferon alpha or association of corticosteroids and or ribavirin to the interferon alpha regimen can attenuate the clinical manifestations of MC and considerably reduce CG production. Different situations can be encountered which may modify treatment strategies: patients may be asymptomatic carriers of cryoglobulins but may have chronic hepatitis according to usual criteria, in some cases, cryoglobulinemic patients have no active liver disease, with normal alanine amino transferase and mild liver lesions at liver biopsy, but severe manifestations of MC, in other patients, active liver disease and MC related symptoms are both present.

Intravenous immunoglobulin therapy in multifocal motor neuropathy: a double-blind, placebo-controlled study

We conducted a double-blind, placebo-controlled, study of 19 patients fulfilling eligibility criteria for multifocal motor neuropathy with persistent conduction block. They were enrolled and divided into two groups: those who had never been treated previously with intravenous immunoglobulins (IVIg) (Group 1: 10 patients) and those who presented recurrent symptoms after previously successful treatment with IVIg (Group 2: nine patients). They were randomized prospectively to receive either IVIg or placebo at a dose of 500 mg/kg/day for 5 consecutive days, once a month for 3 months. At month 4, patients found to be responders remained on the same treatment for the 3 following months, while non-responders were switched to the alternative study drug for the 3 following months. Clinical assessment was conducted with the MRC score in 28 muscles and a self-evaluation scale (five daily motor activities scored from 0 to 5). In Group 1, nine patients completed the study, of whom initially four received IVIg and five placebo; four patients responded to IVIg (two at months 4 and 7, and a further two at month 7 after switching treatment at month 4), two patients responded to placebo at months 4 and 7, and three patients did not respond to either treatment. In Group 2, nine patients completed the study. Five patients first received IVIg and all responded at months 4 and 7. Four patients first received placebo and none responded at month 4; all were then switched to IVIg and three responded at month 7. When the 18 patients were considered together, seven out of the nine patients who received IVIg first were responders at month 4, compared with two of the nine patients who received placebo first, a difference that was statistically significant (P = 0.03). On the other hand, there was no significant difference in MRC score but a significant difference in the self-evaluation score, at month 4, between IVIg patients and placebo patients. Electrophysiological studies did not show significant differences at month 4 in motor parameters between IVIg patients and placebo patients. IgM anti-GM1 titres did not change significantly in patients treated with IVIg compared with those who received placebo, between baseline, month 4 and month 7. However, of five patients who had significantly high anti-GM1 titres (>3200) at baseline, four responded to IVIg. This trial confirms that IVIg is a promising therapeutic option for multifocal motor neuropathy.

Systemic vasculitis in patients with hepatitis C

OBJECTIVE

To analyze the main characteristics of patients infected with hepatitis C virus (HCV) presenting with different types of vasculitis syndrome.

METHODS

We retrospectively compared 2 groups of patients with HCV presenting with systemic vasculitis: 10 with biopsy proven polyarteritis nodosa-type systemic vasculitis (PAN, Group 1) and 7 with mixed cryoglobulinemia syndrome (MC, Group 2).

RESULTS

Patients of Group 1 presented with different features than Group 2: life threatening systemic vasculitis (10 vs 0; p < 0.01), severe multifocal sensorimotor mononeuropathies versus distal moderate sensory polyneuropathies, malignant hypertension (5 vs 0; p = 0.04), cerebral angiitis (2 vs 0), ischemic abdominal pain (2 vs 0), kidney and liver microaneurisms (2 vs 0), increased erythrocyte sedimentation rate and C-reactive protein (7 vs 0; p < 0.01), renal insufficiency (5 vs 0; p = 0.04), HCV genotype 1b (3 vs 6; p = 0.06), and lower activity of chronic hepatitis (p = 0.02). Neuromuscular biopsies showed lesions of vasculitis in all patients, but the type of vasculitis was different in Group 1 compared to Group 2: medium size artery involvement (7 vs 0; p < 0.01), necrotizing vasculitis (10 vs 0; p < 0.01), and mononuclear cell infiltrate in perivascular areas (0 vs 7; p < 0.01). Using prednisone, plasma exchanges, and interferon-alpha, complete recovery was obtained in all PAN-type patients except one. In Group 2 patients, interferon-alpha did not have any effect on the peripheral neuropathy.

CONCLUSION

HCV infection may be associated with different types of systemic vasculitis, i.e., polyarteritis nodosa or mixed cryoglobulinemia. Because of differences in clinical and pathological features and therapeutic strategy, PAN-type vasculitis should be distinguished from MC-type vasculitis in HCV patients.