In an investigation of specific haematological defects that might account for the haemorrhagic diathesis in certain smallpox patients, 93 patients with haemorrhagic and non-haemorrhagic forms of the disease were subjected to a variety of bleeding and coagulation studies. The findings indicate that smallpox patients with no clinical evidence of haemorrhage have no significant clotting defects although many have decreased platelets and clot retraction abnormality. Patients with the late haemorrhagic form of smallpox consistently show thrombocytopenia and associated abnormalities in the bleeding time, tourniquet test and clot retraction; some also have slightly depressed specific prothrombin activity.Patients with the severe, and uniformly fatal, early haemorrhagic form have severe thrombocytopenia, a marked decrease in specific prothrombin activity and prolongation of the prothrombin complex times. They also have a marked prolongation of the thrombin time, suggesting the presence of a circulating antithrombin.Both early and late haemorrhagic smallpox patients also have a marked abnormality of prothrombin consumption, indicating impaired plasma thromboplastin production. This finding could be explained by the thrombocytopenia present in all haemorrhagic cases.

Blood Coagulation Disorders↗

PubMed1965

Haemorrhagic smallpox. 2. Specific bleeding and coagulation studies.

A total of 60 patients in Madras with haemorrhagic and non-haemorrhagic clinical forms of smallpox were investigated by a variety of bleeding and coagulation studies in an attempt to reveal specific haematological defects that might account for the haemorrhagic diathesis in certain cases of smallpox.The non-haemorrhagic smallpox patients had no coagulation abnormalities, although some had thrombocytopenia.The early haemorrhagic patients showed a deficiency of platelets, prothrombin and accelerator globulin, and increased circulating antithrombin. Patients with the late form of haemorrhagic smallpox showed significant thrombocytopenia and less severe deficiencies of the same coagulation factors; a few also had increased antithrombin.The authors suggest that therapy with fresh, frozen or lyophilized plasma should be tried; fresh, platelet-rich plasma should offer the greatest benefit.

Blood Coagulation↗

PubMedDate not supplied

The acridine orange viability test applied to bone marrow cells. II. Correlation with an in vivo irradiated mouse assay.

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Acridines↗

PubMedDate not supplied

Experience with donors matched for minor blood group antigens in patients with sickle cell anemia who are receiving chronic transfusion therapy.

Clinically significant alloimmunization to red cell antigens occurred in 28 percent of transfused patients in a sickle cell clinic. Therefore, a prospective study was undertaken to determine whether matching donors carefully for 17 blood group antigens would diminish the risk of further alloimmunization in patients on a chronic transfusion program. Alloantibodies had developed previously in 8 of the 12 patients. After chronic transfusion with selected donors, four new antibodies developed in three patients. Three antibodies were due to errors in phenotyping or matching, and one was due to an antigen that was not tested for in the protocol. The incidence of developing antibodies per unit transfused was diminished tenfold when selected donors were used. Autoantibodies developed in five patients (42%), but these did not seriously interfere with the transfusion therapy. It was concluded that matching for red cell antigens may diminish the incidence of alloimmunization in patients with sickle cell anemia requiring transfusion.

Anemia, Sickle Cell↗

PubMedDate not supplied

Sickle cell screening.

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Anemia, Sickle Cell↗