Platelet indices have been reported to be associated with multiple diseases of the immune system and hemopoietic system.[17] In our study, we found MPV and PCT were significantly decreased in DM combined with TB (TB + DM) than those in DM individuals. The indices of MPV were higher in DM combined with TB than those in TB patients. The increase of MPV was correlated with ESR and CRP in the DM combined with TB patients. As for the indices of PLT and PDW, there was no significant change between in TB, DM, and TB combined with DM and in healthy controls. Moreover, the factors of age and gender did not significantly affect MPV and PLT indices.
The MPV reflects platelet size and extent of inflammation, and which used to reveal the function of platelet. The platelet size is associated with the inflammatory intensity.[18] In patient infected by Mycobacterial tuberculosis, acute phase reactants and pro-inflammatory cytokines affect megakaryocyte, which decreased the platelet size, and smaller platelets are delivered from the bone marrow,[19] this can be used to explain the reason of MPV decrease. Tozkoparan E et al. found PDW and PCT were higher in the active TB patient and decreased significantly after anti-tuberculous therapy.[10] Sahin et al. indicated that MPV in active TB patients was identical to healthy individuals and non-specific pneumonia patients.[12] These results were in accordance with our findings that there have no significant differences between TB patients and healthy controls. Gunluoglu et al suggested that the value of MPV was slightly decreased in TB patient, the MPV never reflect severity of the tuberculosis.[13]
ESR also has been regarded as a predictor of inflammatory and autoimmune diseases. In principle, the increase in ESR can be due to changes in serum proteins, or it can be due to changes in erythrocytes. The former usually includes hypergammaglobulinemia, monoclonal blood diseases, and elevated fibrinogen levels. The latter is mainly to reduce the number of erythrocyte and the size of erythrocyte.[20] Our results displayed that MPV, but not PLT, correlated with ESR in TB patients with DM. thus, it can be deduced that, as an index of blood in patient with TB and DM, maybe, MPV is an important hematological indicator to evaluate the risk of TB and DM along with ESR.
It is well known that diabetes mellitus (DM) is a metabolic dysfunction characterized by hyperglycemia, which leads to vascular complications. TB is an immemorial and common infectious disease. DM and TB co-morbidity is a widely public health issue. The number of TB patient with DM is much more than the number of TB patient with HIV. Previous studies have shown that DM is a strong risk factor of the development of TB. DM patient are three times risk to develop TB compared to the non-diabetic inhabitant.[21] The increasing prevalence of DM is turning into a challenge to TB prevalence and vice versa.[22] Reinforced the management of DM and improving glycemic control can improve the treatment outcomes of TB.[23, 24] Tuberculosis often worsen glycemic control in patients with DM.[25] Other studies have indicated that TB increases the risk of DM in those previously unknown to be diabetic.[26] There is still a lack of knowledge and assessment whether TB makes individuals susceptible to DM. Several cross-sectional studies have displayed the relationship between TB outcome and the occurrence of hyperglycaemia.[27] As DM and TB worsen in low- and middle-income countries, WHO and the International Union Against Tuberculosis and Lung Disease (IUATLD) encourage the establishment of a cooperative framework that recommends two-way screening including TB testing among individual with DM.[28] WHO recommends screening for DM at the start of TB treatment; however, little is unclear which indicators of blood samples and which patients are at risk for developing TB.
MPV detection and assay are generally valid in clinical as it is routinely detected. MPV is increased in intestine diseases, respiratory diseases, cardiovascular diseases, cerebral stroke, several cancers and diabetes. Conversely, MPV is decreased in the disease of ulcerative colitis, neoplasm, SLE and tuberculosis. The mechanisms for an increased MPV are not well clarified. Several factors may influence MPV value, including genetic variations, applied treatment drugs, lifestyle (diet, smoking, alcohol consumption, and physical activity), pre- and analytical procedures, hormonal profile, age, gender and race/ethnicity.[9] A major aim of this study is the comparison of platelet indices (MPV and PCT) and ESR in DM, TB and DM with TB patients in order to assess that TB or DM is at the risk for developing TB combining with DM. Among diabetes, MPV and PCT were lower in those with tuberculosis as compared to those without tuberculosis. Screening for TB or DM through platelet indices may improve early TB-DM co-morbidity detection and diagnosis. This analytical performance serves a clinical goal and establishes a diagnosis standard for the clinical laboratory.