An evaluation of mean platelet volume, sedimentation, and crp in brucellosis patients platelet sedimentasyon

Aim: Brucellosis is an important infectious disease in Turkey and our region. Mean platelet volume(MPV) is a marker of platelet function, production, and activation. The purpose of this study was to evaluate the relation between epidemiological characteristics of brucellosis patients and MPV and other inflammatory markers. Material and Methods: Brucellosis patients hospitalized for monitoring at the Infectious Diseases Clinic in 2007-2015 were included in the study. One hundred patients with positive tube agglutination tests and/or with bone marrow culture growth, and 100 controls group without diagnosis of brucellosis were enrolled. Patients’ MPV, sedimentation, and CRP values were compared with those of the controls. Results: Men constituted 64% of the patients were men, and the mean age of the patient group was 37.33±16.88 years. The control group consisted of 62% men, with a mean age of 40.35±15.46. There was no statistically significant difference between patients and controls in terms of age or sex. CRP, MPV, and sedimentation were significantly higher in patients with brucellosis than in the controls. Conclusion: MPV is novel, low cost, easily applied marker. It may be of greater value when assessed together with other inflammatory markers. Our findings suggest that MPV values may be a useful inflammation marker and prognostic factor in brucellosis patients.


Introduction
Brucellosis is a zoonotic, inflammatory, systemic infectious disease [1]. It remains an important public health problem in Turkey and developing societies. In Turkey, it is most common in the eastern, southeastern, and central Anatolian regions [2,3]. The incubation period is 2-3 weeks. Transmission is frequently via the gastrointestinal system, conjunctiva, skin, and inhalation [1,3,4,5]. The most common symptoms are elevated body temperature, listlessness, lack of appetite, sweating, and muscle and joint pains. The bacterium has a high affinity for the organs of the reticuloendothelial system (liver, spleen, bone marrow, and lymph nodes) [1,4]. Hematological complications such as anemia, thrombocytopenia, and leukopenia are therefore frequently reported in acute brucellosis [5,6,7]. Severe thrombocytopenia is rare.
Hypersplenism, reactive hemophagocytosis, and immune system breakdown have been implicated as probable causes of thrombocytopenia [8]. Platelets play a major role in thrombus formation [9]. In addition to hemostasis, they also play an active role in antimicrobial host reponse, such as inflammation and tissue repair [8,10].
Despite numerous recent scientific advances, it is still difficult to diagnose, treat, and monitor brucellosis in endemic areas [11]. Diagnosis is based on clinical manifestation, culture results, and serological investigation [1, 119. Laboratory findings may also be normal in some cases [7]. The inflammatory process in brucellosis occurs with an increase in acute phase reactants [11].
Easily studied, inexpensive markers are needed in brucellosis.
MPV is a marker of platelet function and activation that can be investigated in routine blood tests, involves no additional costs, and is easy to apply [7,9]. It is also the most studied platelet activation marker [11]. MPV is a good indicator of platelet activation, production, and function [5,8,9,11,129. It can be affected by cardiovascular risk factors such as smoking, diabetes, obesity, dyslipidemia, and hypertension [8,9].
The purpose of this study was to evaluate risk factors, and clinical and laboratory findings of brucellosis patients hospitalized in our clinic for treatment, and to determine the relations between patient and control group MPV and other acute phase reactants.

Ethics Approval
The study was approved by Ataturk University Faculty of Medicine.

Statistical Analysis
Statistical analysis was performed on SPSS 20 software (Chicago, IL, USA) and using descriptive statistics. Categorical variables were expressed as percentages and frequencies, and continuous variables as mean plus standard deviation. Since these variables were not normally distributed, comparison of patient and control group MPV, platelet, ESR and CRP values was performed using the Mann Whitney u test and the chi-square test. p values <0.05 were regarded as statistically significant.

Results
Sixty-four patients (64%) were men and 36 (35%) were women, MPV values were significantly higher in the patient group than in the control group (p=0.008). Significant elevation was also observed in sedimentation and CRP in the patient group (p< 0.001) ( Table 3).  MPV is a simple parameter routinely measured at complete blood count [7,8,11,12] and is the most studied indicator of platelet activation. In addition to endothelial adhesion and aggregation, platelet activation also plays a role in the upregulation of the inflammatory process [20]. MPV serves as a negative or positive acute phase reactant in diseases progressing with inflammation.
It may increase or decrease, depending on the intensity of systemic inflammation [5,9,21]. We determined higher MPV values in the patients than in the controls.
MPV has been used as a risk marker in diseases associated with atherosclerosis. It is also reported to be capable of reflecting chronic inflammation in diseases such as malignities, cardiac diseases, and liver cirrhosis [18].
Low MPV values have been determined in association with high-degree inflammation in ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, pancreatitis, acute appendicitis, and Familial Mediterranean Fever attacks. High MPV has been linked to low-degree inflammation risk factors causing cardiovascular, cerebrovascular, arterial and venous thrombosis. These diseases include chronic hepatitis B and C, pulmonary hydatid cyst, CCHF, and myocardial infarction [2,9].
MPV increase is explained in terms of release of large platelets into the circulation, and decreased MPV in terms of depletion of platelets in circulation [21]. Some studies have shown that MPV increases with treatment [8,16]. The high MPV values in our patients may be due to the large number of acute cases, greater numbers of large platelets, and an increase in systemic inflammation. One of the limitations of our study is that MPV values were not investigated post-treatment.
Gasparyan et al. [9] reported negative correlation between MPV level and platelet count. They attributed this to an endeavor to keep platelet number at specific levels to maintain equilibrium.
MPV has been widely used in the evaluation of platelet functions in several diseases. Large platelets have a denser granule content than small ones. Large platelets are more active and produce more prothrombotic factor. They contain more prothrombotic substances, such as thromboxane A2.
Glycoprotein Ib, IIb and IIIa receptor expression is also greater.
MPV is a direct marker of increased platelet synthesis. Platelet numbers are disposed to fall in conditions in which MPV increases. This may be due to enhanced production of platelets with greater aggregability or to increased destruction [9,23].
A fall in platelet numbers may be linked to increased platelet activity and aggregated platelets. Information can be obtained concerning platelet activation by examining MPV and platelet count, easily and inexpensively, from complete blood count.
The release of non-mature platelets from bone marrow due to rapid platelet depletion, and the earlier depletion of small platelets has been implicated as the cause of increased MPV in acute coronary syndrome [24]. High MPV has been associated with mortality in ischemic stroke patients [9,22]. We think that elevation in MPV values can be used in acute phase reactant and disease progression evaluation in brucellosis.
The retrospective, cross-sectional and a case controlled nature of the study is its principal limitation. Prospective data comparing pre-and post-treatment values are now needed.
The limiting aspect of this study is its retrospective nature and that blood count values after treatment could not be obtained for all patients.

Conclusion
Brucellosis is an important infectious disease due to its high morbidity rate, the economic burden it imposes, and its ability to affect large numbers of people. Detailed history, family history, and occupational and dietary factors must be investigated. It may assume various different clinical manifestations. Brucellosis must be considered at differential diagnosis in cases of high temperature, articular pains, hematological findings, and various system involvements in endemic regions. MPV is a marker of platelet functions and can be used as an acute phase reactant in determining the activity of the disease and in follow-up in this patient group.
More extensive prospective studies are now needed.