Comparison of major immunoglobulins intrathecal synthesis patterns in Ecuadorian and Cuban patients with angiostrongyliasis

First cases of Angiostrongylus cantonensis infection reported in Martinique, 2002-2017

Neuroangiostrongyliasis is a parasitic disease caused by the accidental ingestion of the nematode Angiostrongylus cantonensis in its larval form. Human infection can lead to eosinophilic meningitis, sometimes complicated by life-threatening radiculomyelitis or encephalitis. Although some cases have been reported from other Caribbean Islands, no cases have been diagnosed in Martinique so far. Here, we report the first eight laboratory-confirmed cases of neuroangiostrongyliasis on the island of Martinique, French West Indies, between 1 January 2002 and 31 December 2017. One case was fatal and five resulted in neurological sequelae. The medical community should consider the risk of A. cantonensis infection in patients living in or returning from Martinique.

First Evidence of Angiostrongyliasis Caused by Angiostrongylus cantonensis in Guadeloupe, Lesser Antilles

Infection by the rat lungworm Angiostrongylus cantonensis represents the most common cause of infectious eosinophilic meningitis in humans, causing central nervous system (CNS) angiostrongyliasis. Most of CNS angiostrongyliasis cases were described in Asia, Pacific Basin, Australia, and some limited parts of Africa and America. CNS angiostrongyliasis has been reported in the Caribbean but never in the Lesser Antilles. The primary objectives of this study were to depict the first case of CNS angiostrongyliasis in the Lesser Antilles and investigate the environmental presence of A. cantonensis in Guadeloupe, Lesser Antilles. In December 2013, a suspected case of CNS angiostrongyliasis in an 8-month-old infant in Guadeloupe was investigated by real-time polymerase chain reaction (PCR) testing on cerebral spinal fluid (CSF). The environmental investigation was performed by collecting Achatina fulica molluscs from different parts of Guadeloupe and testing the occurrence of A. cantonensis by real-time PCR. CSF from the suspected case of angiostrongyliasis was positive for A. cantonensis by real-time PCR. Among 34 collected snails for environmental investigation, 32.4% were positive for A. cantonensis. In conclusion, we report the first laboratory-confirmed case of CNS-angiostrongyliasis in the Lesser Antilles. We identified the presence and high prevalence of A. cantonensis in A. fulica in Guadeloupe. These results highlight the need to increase awareness of this disease and implement public health programs in the region to prevent human cases of angiostrongyliasis and improve management of eosinophilic meningitis patients.

Quantitation of intrathecal immunoglobulin synthesis - a new empirical formula

BACKGROUND AND PURPOSE

Intrathecal immunoglobulin (Ig) synthesis occurs in various chronic inflammatory neurological diseases. Different formulae have been developed for quantitative determination of Ig synthesis within the cerebrospinal fluid (CSF) compartment. The hyperbolic formula of Reiber is frequently used which, however, returns a considerable number of false positive results in empirical observations.

METHODS

A computerized database of more than 19 000 paired CSF and serum samples was screened for patients presumed negative for local Ig synthesis and a new formula characterizing this collective was calculated. The validity of this formula was confirmed by several validation steps.

RESULTS

A cohort of 1173 patients with normal CSF findings was used for quantile regression. The 97.5th quantile of the formula Qlim(IgX)=a×Qalbb was considered as the cut-off curve for intrathecal Ig synthesis using different constants a and b for IgG, IgA and IgM. Compared to the Reiber formula, a lower level of false positive results was produced especially for IgM and IgA which was confirmed in a separate clinically well defined validation cohort. In 77 patients with discrepant findings between Reiber and our formula no specific diagnoses were found confirming the low diagnostic value of borderline Ig synthesis.

CONCLUSIONS

A new approximation formula was developed for determination of intrathecal Ig synthesis which produces fewer false positive results without reducing diagnostic sensitivity.

Central nervous system manifestations of Angiostrongylus cantonensis infection

Over 20 species of Angiostrongylus have been described from around the world, but only Angiostrongylus cantonensis has been confirmed to cause central nervous system disease in humans. A neurotropic parasite that matures in the pulmonary arteries of rats, A. cantonensis is the most common cause of eosinophilic meningitis in southern Asia and the Pacific and Caribbean islands. The parasite can also cause encephalitis/encephalomyelitis and rarely ocular angiostrongyliasis. The present paper reviews the life cycle, epidemiology, pathogenesis, clinical features, diagnosis, treatment, prevention and prognosis of A. cantonesis infection. Emphasis is given on the spectrum of central nervous system manifestations and disease pathogenesis.

Intrathecal activation as a typical immune response within the central nervous system in angiostrongyliasis

Angiostrongylus cantonensis is a zoonotic pathogen that occasionally causes human angiostrongyliasis; its main clinical manifestation is eosinophilic meningitis. This report defines the concept of intrathecal activation of complement as evidence of intrathecal synthesis of major immunoglobulins during this disease. Details are presented of the activation of complement system components in cerebrospinal fluid, and their application to our understanding of this tropical disease, which is emerging in the Western hemisphere. Intrathecal synthesis of at least one of the major immunoglobulins and a wide spectrum of patterns may be observed. Although intrathecal synthesis of C3c is always present, C4 intrathecal synthesis does not occur in every patient. The diversity of intrathecal synthesis and activation of the different complement pathways enables their division into three variant groups (A, B, and C). Variant group A includes the classical and/or lectin pathway and involves two or more major immunoglobulins with C3 and C4 intrathecal synthesis. Variant group B involves C4 in cerebrospinal fluid that comes from blood in the intrathecal activation of the classical pathway. Variant group C includes the alternative pathway.

Benefits and risks of IgA in immunoglobulin preparations

The case of Immunoglobulin A (IgA) in transfusion medicine is unsettled: on one hand IgA is an important component of adaptive immunity and its deficiency may cause disease, on the other its presence in blood products might induce, in rare instances, allergy-like symptoms if not anaphylaxis. The practice with i.v. immunoglobulins currently changes as up to 10% concentrated preparations are given at fast rates hence even trace amounts of IgA contained in these IgG preparations can cause unexpected (side-) effects. Fortunately, the spectrum of sensitive IgA assays, along with anti-IgA screening assays now permits laboratories to narrow down IgA-dependent transfusion reactions to the real cases, in which IgA was the decisive trigger of anaphylaxis, proven or not by the presence of anti-IgA of the IgG or even IgE class. Tolerance to allogenic IgA has recently been reported. The known association of HLA with IgA deficiency (IgAD) has now been completed with an association to the nonsynonymous variant in IFHI1, allowing physicians to more precisely spot recipients at risk for an IgA-dependent transfusion reaction. Our review, along with our own experience here in Switzerland, allows us to conclude that IgA is a beneficial antibody rather than an allergen to be placed at the end of the list of non-infectious transfusion complications such as TRALI, febrile non-hemolytic reactions, purpura or volume overload.