الفهرس 
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Abstract
The main objective of this study was to evaluate the efficiency of platelet indices in differentiating hypo-productive cause of thrombocytopenia from hyper-destructive thrombocytopenia and was to assess platelet functions and bleeding in both groups we examined and compared platelet function and indices in hypo productive thrombocytopenic patients which include; myelodysplasia (MDS), CML, ALL, AML and aplastic anemia, with hyper destructive group which include patients with immune thrombocytopenia (ITP), TTP and DIC, we used flow cytometry to evaluate platelet function as it is more accurate in measuring platelet function in thrombocytopenic patients.
The study was conducted on 80 thrombocytopenic patients who met eligibility criteria at the time of the study (from January 2018 to January 2020) and were presented with signs and symptoms suggesting low platelets count and admitted to the Department of Internal Medicine, Sohag University Hospital, the patients were screened for the underlying cause of thrombocytopenia and were divided into 2 groups in addition to a third group consisted of 20 healthy control persons with normal CBC, patients enrolled in this study divided into: (1) hyper-destructive thrombocytopenic patients group aged 18 years or above which include ITP, TTP, DIC, (2) Hypo-productive thrombocytopenic patients group aged 18 years or above which include aplastic anemia, myelodysplastic syndrome, chronic myeloid leukemia, acute lymphoblastic leukemia, (3) healthy control persons with normal CBC.
We excluded patients less than 18 years old, patients who diagnosed with pseudo thrombocytopenia, patients previously diagnosed with thrombocytopenia and received immunosuppressive therapy, thrombopoietin receptor agonists or chemotherapy, patients diagnosed with thrombocytopenia and received platelets transfusion within 7 days, patients on medication that can affect platelet function (aspirin, clopidogrel, abciximab, etc.….) within 14 days or exposure to procedures or interventions, such as central venous catheter insertion on the day of sampling and patients with chronic kidney disease.
All patients provided their written informed consent after proper counseling before participating in the study and according to the legal requirements. All included patients were subjected to detailed history and complete physical examination with emphasis on abnormal signs as pallor, ecchymosis, purpura, organomegaly or lymphadenopathy.
Also, all patients were subjected to measurement of BMI, laboratory investigations as complete blood picture including platelet indices, serum creatinine, coagulation profile, liver function tests, hepatitis (B, C, HIV) antibodies test by ELIZA, platelet function tests by flow cytometry (CD42b antibodies and CD62P antibodies).
Abdominal ultrasound examination was done to all patients and bone marrow aspiration to thrombocytopenic patients.
Among these patients 36 patients had hyper destructive thrombocytopenia, 44 patients had hypo productive thrombocytopenia and 20 healthy controls, there was high significant difference between them as regards gender (p <0.0001) as the majority of hyper destructive thrombocytopenic patients (83.3%) were females, however (56.8%) of hypo productive thrombocytopenic patients were males. There was significant difference between hyper destructive thrombocytopenic patients and controls as regards age and gender (p< 0.05), as mean age of hyper destructive thrombocytopenic group was higher than controls (p=0.05).
Purpura was a common symptom among hyper destructive thrombocytopenic patients as it was detected in 47.22% of patients, however epistaxis was a common symptom among hypo productive thrombocytopenic patients as it detected in 52.27% of patients.
The platelet counts and indices were compared in the present study between hyper destructive, hypo productive thrombocytopenic patients and healthy controls. We found that hyper destructive thrombocytopenic patients had non-significant higher platelets count than hypo productive thrombocytopenic patients (p=0.5), however platelet indices MPV, PCT and PDW were significant higher (p<0.0001) in patients with hyper destructive thrombocytopenia than hypo productive thrombocytopenic patients.
By comparison between hyper destructive thrombocytopenic patients and controls as regards platelets count and platelet indices, we found that hyper destructive thrombocytopenic patients had higher platelet indices than controls with high significant difference (p<0.0001), but lower platelet counts than controls with high significant difference(p<0.0001).
Also, hypo productive thrombocytopenic patients had lower MPV and PCT and platelet counts than controls with high significant difference (p<0.0001)
As regards platelet’s function test of the studied population, we found that hyper destructive thrombocytopenic patients had higher platelet expression each of CD 42b% positive cell, and CD 62P % positive cell and higher CD 42b-MFI, CD 62P-MFI than hypo productive thrombocytopenic patients with high significant difference (p<0.0001), also hyper destructive thrombocytopenic patients had higher platelet expression of CD 62P MFI and CD 42b-MFI, CD 62P% positive cells than controls with high significant difference (p<0.001, 0.02 respectively).
However, controls had higher each of CD 42b-MFI and CD 42b % positive cell than hypo productive thrombocytopenic patients with high significant difference (p<0.0001).
There was high significant difference between them as regards bleeding score (p<0.001) as hypo productive group had higher bleeding score than hyper destructive group, on the other hand all hyper destructive thrombocytopenic patients had normal abdominal sonar, however 15.91% of hypo productive thrombocytopenic patients had abnormal abdominal sonar in the form of organomegaly.
In this study correlation between platelet count and both indices and function in 3 studied groups, there was negative and high significant correlation between platelet count and MPV in hyper destructive group, furthermore, we found that platelet count was positive and significant correlated with PCT in the 3 groups.
On the other hand, when correlation between bleeding score and platelet count, indices and function was performed in thrombocytopenic groups, we found that bleeding score was negative and significant correlated with MPV in hyper destructive thrombocytopenic group.
Sensitivity and specificity were extrapolated from different coordinate points of the ROC curve. In the present study, the platelets indices (MPV, PCT, and PDW) have better sensitivity, specificity and predicative value in discriminating the two types of thrombocytopenia. MPV ≤8.9 can identify hypo productive cases among thrombocytopenic patients with 90.9% sensitivity, 94.4% specificity, 95.2% PPV, 89.5% NPV.
Conclusion:
Platelet indices specially (MPV, PDW) may provide some useful information in discriminating the hypo productive and hyper destructive cause of thrombocytopenia. Thus, interpretation of these platelet indices can help the patients to avoid unnecessary invasive investigations like bone marrow aspiration and unnecessary platelet transfusion.
Platelet count alone does not always predict bleeding so tests for platelet functions should also be considered, flow cytometry considered a good tool to evaluate platelet function in thrombocytopenic patients.
Recommendations:
• Further studies with larger number of patients in each subgroup are needed to explore the role of these platelet indices in thrombocytopenia and their diagnostic role in other diseases. Therefore, cut off values need to be established on the given laboratory setup and place for the indices to be used as a discriminating tool for thrombocytopenia.
• Further studies are needed to measure and compare platelet function in both groups with immature platelet fraction (IPF) and comparing platelet functions in hyper destructive thrombocytopenic patients against those in hypo productive thrombocytopenic patients who experienced bleeding and in absence of bleeding.