ИММУНОФЕРМЕНТНЫЙ АНАЛИЗ БЕЛКА S-100 В СЫВОРОТКЕ КРОВИ, КАК СПОСОБ РАННЕЙ ДИАГНОСТИКИ РАССЕЯННОГО СКЛЕРОЗА И ОЦЕНКИ ЭФФЕКТИВНОСТИ ПАТОГЕНЕТИЧЕСКОЙ ТЕРАПИИ

Чичановская Л.В.¹, Сорокина К.Б.²

¹ Доктор медицинских наук, ² ассистент кафедры,

Тверской государственный медицинский университет

ИММУНОФЕРМЕНТНЫЙ АНАЛИЗ БЕЛКА S-100 В СЫВОРОТКЕ КРОВИ, КАК СПОСОБ РАННЕЙ ДИАГНОСТИКИ РАССЕЯННОГО СКЛЕРОЗА И ОЦЕНКИ ЭФФЕКТИВНОСТИ ПАТОГЕНЕТИЧЕСКОЙ ТЕРАПИИ

Аннотация 

Заболеваемость рассеянным склерозом во всем мире увеличивается с каждым годом и встречается наиболее часто  у лиц молодого возраста (18-55 лет)  и характеризуется постепенным нарастанием неврологического дефицита, а также  приводит к инвалидизации пациентов. Для того чтобы установить диагноз пациенту иногда требуются месяцы и годы, так как процесс демиелинизации должен распространиться в месте и времени (Критерии Макдональда 2005-2010). В связи с этим, существует необходимость выявления диагноза у пациентов с самого начала заболевания, так  как чем раньше начата патогенетическая терапия тем менее выражены впоследствии процессы инвалидизации пациента с РС.

Ключевые слова: рассеянный склероз, иммунологическая диагностика, S-100 белок

Chichanovskaya L.V.¹, Sorokina K.B.²

¹ MD, ² Postgraduate student, teaching assistant,

Tver State Medical University

ENZYME IMMUNOASSAY FOR ESTIMATION OF S100 PROTEIN IN BLOOD SERUM AS A METHOD OF EARLY DIAGNOSIS AND EFFICIENCY ASSESSMENT OF MULTIPLE SCLEROSIS PATHOGENETIC THERAPY

Abstract

The incidence of multiple sclerosis (MS), a disease that primarily affects people between the ages of 18 and 55, has been steadily increasing all over the world. MS is associated with a progressive increase of neurological deficit and is one of the main causes of disability. It sometimes takes a few months or even years to diagnose MS as the demyelination process has to spread in space and time (the 2005-2010 McDonald Criteria). Therefore, it is of importance to make the diagnosis at the early symptoms of the disease, because the earlier pathogenetic therapy results in less evident disability processes in MS patients.

Keywords: multiple sclerosis, enzyme immunoassay, S-100 protein

 

Introduction

Multiple sclerosis (MS) is a chronic progressive disease of the CNS that primarily affects young and middle-aged people [5]. The incidence of MS has been steadily increasing over the past decade and becoming an important social problem both for the medical community and society in general, as it is one of the main causes of disability. [1]; [2]; [3].

The aim of our study was to determine the link between the parameters of the neuroglial astrocyte-specific protein S-100 and the severity of disability depending on the duration of the disease and the type of the basic therapy.

Material and methods

Venous blood samples (5ml) were obtained from the patients on an empty stomach by venipuncture of the cubital vein and centrifuged immediately at 10,000 rpm for 10 min (laboratory centrifuge ПЭ-6900). Then the serum samples were collected into sterile test tubes and delivered to the clinical diagnostic laboratory of the Tver Regional Clinical Hospital. The parameters of S-100 protein were determined using the enzyme immunoassay kit for estimation of the S-100 calcium-binding protein (“Geropharm”, Russia). The data were collected and organized in the table.

The data collected were analyzed with the “Statistica 6.0” program. The Pearson correlation coefficient significance was assessed with the subprogram “PearsonCorrelationSignificance”.

Results and discussion

We screened a total of 120 randomly selected patients with confirmed MS. 40 of the patients had the early symptoms (onset) of the disease, 40 had been suffering from MS for 1-5 years, another 40 – for more than 5 years. The results of the investigation and analysis of the data received are presented in Table 1.

Table 1. S-100 mean values and duration of MS.

NB: differences between the mean values are statistically significant (variance analysis, p=0.002, Dunnett’s test showed all differences as statistically significant).

Therefore, it has been revealed that patients during the onset and the first 5 years of the disease see an increase in the neurospecific protein S100, which can be an indicator of the severity of the damage to the cerebral tissue and a predictor of an unfavourable outcome as a method of MS early diagnosis. As seen from Table 1, the longer diagnosis of MS and more progressive neurological deficit are associated with a decreased level of the S100 protein, which may be linked to the autocrine effect on the astrocytes, stimulating their regeneration, having a trophic effect on the developing and regenerating neurons.

We have also investigated the dependence of the S100 protein in MS patients on the type of disease modifying therapies (DMTs). From the sample, we selected 90 patients with the MS diagnosis of 1 year and longer who received an immunomodulatory therapy: 30 of them took glatiramer acetate, 30 – interferon β-1b and another 30 – interferon β-1a (See Table 2).

Table 2. Dependence of the S100 protein level on the type of DMT

NB: differences between the mean values are statistically significant (variance analysis, p=0.002, Dunnett’s test showed statistically significant differences between the Interferon β-1b group and the other groups. The difference between the Glatiramer acetate group and the Interferon β-1a group was not statistically significant.).

As seen from Table 2, the patients in the Glatiramer acetate group had a low level of S100 protein in the blood serum (mean value -- 0.309 mkg/k). In the Interferon β-1a group the mean value of S100 protein was 0.377 mkg/l, in the Interferon β-1b group it was 0.493 mkg/l.

The low level of the neurospecific indicator of the brain lesion in patients taking glatiramer acetate can be associated with the structure of the drug being a random polymer composed of four amino acids. Given its resemblance to myelin basic protein, glatiramer acetate diverts an autoimmune response against myelin.

The higher level of the S100 protein in patients taking interferons can be related to the fact that the drugs of this group are a “copy” of interferon β which is the natural protein component produced in the human body. The therapeutic effect of this drug is achieved due to the enhanced immune cell response. As a result, the immune system attacks the nerve cells, which probably leads to the elevated rate of S-100 protein the blood serum as a reaction to the immune cell response.

In the studied cohort, we observed increased levels of S-100 protein in the patients with early symptoms of MS and those suffering from MS for 1-5 years. It can be associated with the severity of the cerebral tissue lesion, expression of the demyelination process and early stage of MS. The longer diagnosis of MS and more progressive neurological deficit (see Table 2) are associated with decreased levels of S-100, which can be related to the processes of neurodegeneration in the CNS after 5 years of the disease. The parameters of the neurospecific protein S-100 depend on the DMT received by the patients. The higher levels of the protein have been revealed in patients taking interferon β, while the lower levels have been revealed in those taking glatiramer acetate which may be linked to different components of the drugs and therefore different pathogenetic effects of the therapies.

Conclusions

As a result of the investigation we have come to the conclusion that the level of the S-100 protein is significantly higher during the onset of the disease as compared to the period of 1 year and longer. That is why this method can be used for early diagnosis of MS. We have also received data on parameters of the neuroglial astrocytic protein in patients receiving different DMTs which can be used for assessment of pathogenetic therapy received by MS patients.

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