[Inflammatory syndrome of unknown origin and PET/CT: Economic and iatrogenic impacts of false positive]

INTRODUCTION

PET/CT is regularly used to investigate inflammatory syndrome of unknown origin (IUO), but hypermetabolisms found are not always consistent with the final diagnosis. The objective of the study was to assess the cost attributed to the diagnostic work-up for these false positives.

MATERIALS AND METHODS

We conducted an ancillary study on a previous retrospective cohort from the internal medicine department at Amiens university hospital in patients who had a PET/CT scan between October 2004 and April 2017. Patients were included if PET/CT had been prescribed to investigate IUO. Among the 763 PET/CT performed, 144 met the inclusion criteria and a false-positive rate of 17.4% (n=25) was reported.

RESULTS

Among these 25 patients, 21 underwent further investigations. The most frequently found hypermetabolic territories were digestive (n=12, mean SUVmax 8 [±4.33]) and osteoarticular (n=11, mean SUVmax 4.33 [±1.15]). The total cost of the 13 prescribed consultations was €390, the total cost of the 40 additional tests was €4,476 (mainly digestive endoscopies and radiological tests) and the total cost of medical transport was €572. The total cost of the 35 days of hospitalization specifically required to investigate these false positives was €22,952. In 23.8% (n=5), these investigations led to the incidental discovery of tumor lesions.

CONCLUSION

The economic impact of false-positive PET/CT results does not appear to be negligible and merits a genuine prospective medico-economic study.

Troubles mnésiques persistants post-COVID-19 : intérêt de la recherche des anti-SARS-CoV-2 dans le LCR couplée à la spectro-IRM cérébrale ?

Introduction

La maladie post-COVID-19 se développe quelle que soit la gravité de l’infection à SARS-CoV-2 initiale et comporte un large éventail de manifestations cliniques parmi lesquelles figurent de nombreux troubles neurologiques tels que les céphalées, l’anosmie, des troubles de la mémoire….

Observation

Nous rapportons le cas d’une patiente âgée de 68 ans adressée en consultation de médecine interne pour asthénie, troubles de la concentration et de la mémoire dans les suites d’une infection à SARS-CoV-2. Ses antécédents sont marqués par une HTA, un asthme, une thrombose veineuse profonde, une cholécystectomie, un œdème de Quincke avec choc anaphylactique aux AINS et une hypogammaglobulinémie modérée. On note une absence d’intoxication alcoolo-tabagique. La patiente a présenté en janvier 2021 une infection à SARS-CoV-2 avec fièvre et céphalées. La recherche de virus par PCR était négative lors de cet épisode avec secondairement une sérologie positive confirmant l’infection. Progressivement sont apparus des troubles de la mémoire et de la concentration. Son MMS était à 27/30.

L’IRM cérébrale en juin 2021 montrait de multiples hypersignaux de la substance blanche.

Un bilan a été réalisé en hôpital de jour avec réalisation d’une ponction lombaire.

Le LCR retrouvait l’absence de leucocytes (< 1 élément/mm³), des hématies à 24 éléments/mm³ et une protéinorachie à 0,45 g/L.

Les anticorps anti-rNMDA, anti-CASPR2, anti-rGABAb, anti-DPPX, anti-LGI1 et anti-AMPAr dans le LCR étaient négatifs.

Absence de bande surnuméraire à l’isofocalisation.

Les anticorps anti-SARS-CoV-2 dans le LCR étaient positifs à 108,7 UA/mL, la recherche de virus par PCR étant négative.

Le rapport de Delpech était normal à 0,52 mais n’excluant pas une synthèse intrathécale d’IgG. Par ailleurs, l’index albumine LCR/albumine sérum était normal.

Une polysomnographie ne retrouvait pas de syndrome d’apnées du sommeil.

Une spectroscopie par IRM cérébrale en mai 2022 a mis en évidence une réaction gliale ainsi qu’une dysfonction neuronale au niveau de l’hippocampe et de la protubérance.

Discussion

Les séquelles neuropsychologiques post-COVID-19 témoignent d’une neuro-inflammation liée à l’activation de la microglie et à une réaction auto-immune [1]. La persistance de troubles cognitifs associée à la présence d’anticorps anti-SARS-CoV-2 dans le LCR 6 mois après COVID-19 a été rapportée chez une patiente de 57 ans [2]. Dans notre observation, la présence de ces anticorps peut témoigner d’une neuro-inflammation constatée sur la spectroscopie par IRM cérébrale. Une exploration biologique plus approfondie du LCR ainsi qu’une exploration par spectroscopie par IRM cérébrale pourraient être suggérées chez les patients présentant des troubles cognitifs plusieurs mois après une infection à SARS-CoV-2.

Conclusion

D’autres études seront nécessaires afin de mieux définir la place de la recherche des anticorps anti-SARS-CoV-2 dans le LCR chez les patients ayant des séquelles neurologiques majeures liées au COVID-19.

[Seronegative antiphospholipid syndrome: Myth or reality?]

The antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by thrombosis and/or obstetrical manifestations and the persistent presence, at least 12 weeks apart, of antiphospholipid antibodies (aPL) such as lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACL) and/or anti-β2 glycoprotein I antibodies (aβ2GPI). The finding of patients with clinical profile highly suggestive of APS but who are negative for conventional biological criteria has led to the concept of seronegative APS. In the last few years, new antigen targets and methodological approaches have been employed to more clearly identify this syndrome in patients with thrombosis or obstetrical complications without conventional aPL. Although seronegative APS is still controversial, there is increasing recognition of the existence of this subgroup. However, clinical relevance of non conventional aPL need to be confirmed by efforts toward standardizing new biological tools and longitudinal studies involving large cohort of patients.

Antibodies directed against annexin A2 and obstetric morbidity

Acquired and inherited thrombophilia have both been reported to be associated with an increased risk of obstetric complications in early or later stages of pregnancy. Annexin A2 (ANXA2) is strongly expressed in vascular and placental tissues and plays a crucial role in fibrinolysis. The aim of the present study was to evaluate the prevalence of antibodies directed against ANXA2 in patients with recurrent miscarriage or obstetric complications. Anti-ANXA2 antibodies (aANXA2) were detected by ELISA in the sera from 46 women with obstetric morbidity, mainly recurrent miscarriage. The cut-off value for positivity was defined as 3 standard deviations above the mean optical density (OD) obtained in the sera from 42 female blood donors. The prevalence of aANXA2 in patients and healthy individuals was 15.2% and 2.3%, respectively. A statistically significant difference was observed between the 2 groups in terms of aANXA2 IgG titers (p=0.01). The highest aANXA2 levels were observed in sera from 2 patients with recurrent miscarriage and one patient with preeclampsia. aANXA2 could play a role in thrombotic mechanisms leading to recurrent pregnancy loss and placental vascular disease. Further studies are needed to determine whether ANXA2 is critical for maintenance of placental integrity.

Autoantibodies recognizing the 27 carboxy-terminal amino acids of calpastatin are associated with secondary Sjögren syndrome in systemic lupus erythematosus

The objective of this study was to determine in systemic lupus erythematosus (SLE) the prevalence and clinical significance of anticalpastatin antibodies (ACAST), an autoantibody population previously detected in sera from patients with various connective tissue diseases. Eighty-four patients with SLE (mean age: 30 years at diagnosis, females 77) that fulfilled ACR criteria were included in the study retrospectively. Several clinical and biological data were collected. ACAST were detected by a solid-phase enzyme linked immunosorbent assay (ELISA) using as antigen a synthetic peptide corresponding to the 27 C-terminal amino acids of calpastatin (CAST-C27). The prevalence of ACAST-C27 was 13% (11/84) in SLE patients. No correlation was found between the presence of ACAST-C27 and clinical manifestations such as thrombosis and vasculitis. Furthermore, no correlation was observed with the presence of antiphospholipid antibodies (APL). However, we found a statistically significant association between the presence of ACAST-C27 and that of secondary Sjögren syndrome ( P = 0.01). The conclusion is ACAST-C27 are not associated with thrombosis in SLE patients. The association observed between ACAST-C27 and secondary Sjögren syndrome suggests that ACAST-C27 might be useful in discriminating a clinical subgroup of SLE patients.

Vascular expression of annexin A2 in lupus nephritis

AIMS

To evaluate vascular expression of annexin A2 (ANXA2) and its subunit S100A10 in lupus nephritis (LN).

METHODS

The present histological study included 14 patients with LN and 11 controls (patients with non-lupus kidney diseases). Kidney biopsies from patients with lupus were scored for lupus glomerulonephritis (according to the International Society of Nephrology/Renal Pathology Society 2003 classification) and vascular lesions (such as microthrombi and antiphospholipid syndrome nephropathy (APSN)). ANXA2 and S100A10 expression in glomerular and peritubular capillaries was evaluated by immunohistochemistry on tissue sections. The staining intensity score ranged from 0 (no expression) to 4 (intense expression).

RESULTS

In patients with LN, the median age (range) at first kidney biopsy was 36 (18-49). Vascular lesions were observed in six patients (including two with APSN). We observed intense expression of ANXA2 in glomerular and peritubular capillaries while expression of S100A10 was weaker. However, one of the patients with APSN showed strong S100A10 expression. Patients with LN and controls differed significantly in terms of S100A10 expression in peritubular capillaries. We also observed a statistical difference between patients who had LN with renal vascular lesions and those without renal vascular lesions in terms of ANXA2 expression in peritubular capillaries.

CONCLUSIONS

The presence of vascular lesions in LN appears to be associated with significant differences in the vascular expression of ANXA2. Vascular expression of ANXA2 was somewhat higher in LN. Vascular expression of S100A10 was somewhat lower in LN (except one of the two patients with APSN). Further studies of ANXA2's putative value as a biomarker of active LN or of vascular lesions in LN are required.