Thrombocytosis. Etiologic analysis of 663 patients.

Six hundred sixty-three children aged 1 to 16 years with thrombocytosis (defined as a platelet count of more than 500 x 10(9)/L) seen in a university hospital over a 1-year period were studied prospectively for etiology. The causes of thrombocytosis were infection (30.6%), hemolytic anemia (19.3%), tissue damage (15.2%), rebound thrombocytosis (14.8%), chronic inflammation (4.1%), renal disorders (4.1%), and malignancy (2%). Thrombocytosis associated with multiple, simultaneous causative factors was seen in 3.3% of cases. Among all patients with infections, osteomyelitis and septic arthritis were associated with higher platelet counts than other infections (P < .0001). Thrombocytosis secondary to infections was significantly more common in children under 5 years of age, whereas chronic inflammation, malignancy, and renal disorders were more common causes of thrombocytosis in children over 5 years of age. Thrombocytosis of 1 million or more platelets was seen in 13 (2%) children. No thrombocytosis-related complications were seen in any children, and none required any specific treatment. Thrombocytosis is a frequent finding in children. It is due to a variety of etiologic factors and is of little clinical discriminatory value. It is often due to an acute-phase phenomenon in response to infection, tissue damage, blood loss, or anemia, and is rarely due to malignancy.

Pancytopenia in children with brucellosis: clinical manifestations and bone marrow findings.

Among 276 paediatric cases of brucellosis seen over a 7-year period, 16 patients (5.8%) with pancytopenia were identified. The most frequent presentations were fever, malaise, anorexia, weight loss, arthralgia, and hepatosplenomegaly. Fourteen patients (87.5%) had positive blood and/or bone marrow cultures for Brucella melitensis. Bone marrow aspiration specimens showed hypercellularity in 14 patients and normocellularity in 2. Histiocytes, eosinophils and plasma cells were increased in every marrow aspirate, and haemophagocytosis was observed in 14 patients (87.5%). Non-caseating granulomas were present in the bone marrow biopsy of 11 patients (68.8%). The pancytopenia was transient, and resolved on treatment of the Brucella infection.

Pernicious anemia in Saudi Arabs.

Over a five-year period extending from January 1986 to December 1990, seven cases of pernicious anemia in Saudi patients were diagnosed at King Khalid University Hospital in Riyadh. There were five males and two females. The age range was 45 to 73 with a mean age of 61 years. The presenting symptoms, laboratory features and the disease pattern were similar to those described in northern European patients with the possible exception of male predominance in our patients. One patient demonstrated an interesting phenomenon of masking the macrocytosis of pernicious anemia by concurrent beta thalassemia minor. No association with any other autoimmune diseases was detected in any of our patients.

Thrombocytosis in adults: analysis of 777 patients.

A total of 777 patients with thrombocytosis, defined as a platelet count of greater than 500 x 10(9)l-1, seen in a University hospital over a 1-year period, were studied prospectively for aetiology. The most frequent causes of thrombocytosis were infection (21.9%), rebound thrombocytosis (19.4%), tissue damage (17.9%), chronic inflammatory disorders (13.1%) and malignancy (5.9%). Thrombocytosis associated with multiple causative factors, occurring simultaneously, was seen in 6.1% of cases. Thrombocytosis of greater than or equal to 1 million x 10(9)l-1 was found most frequently in patients with multiple aetiological factors occurring at the same time, in myeloproliferative disorders, or in postsplenectomy patients.

Hairy-cell leukemia with T-cell features.

A case of clinically and hematologically typical hairy-cell leukemia has been presented in which, at the various times of testing, 52%-95% of peripheral blood and 73% of splenic mononuclear cells formed spontaneous sheep erythrocyte (E) rosettes. Many of the rosetting cells were shown to be typical morphologic hairy cells by light and electron microscopy. It was found that 70%-75% of peripheral blood mononuclear cells stained with an anti-T antiserum, and this antiserum also abolished E-rosette formation. A variable percentage of peripheral blood mononuclear cells was also shown to bear surface (IgDK) and internal (IgMK and IgGK) immunoglobulins. Additional B-cell features demonstrated included possession of the P29/34 la-like antigen and formation of mouse rosettes. It was demonstrated by a variety of blocking and inhibition studies that the E-rosette formation was not attributable to chance antigen specificity of the surface membrane immunoglobulin. These marker studies suggest that this is a case of true hybrid cell HCL. Despite these unusual marker characteristics, the patient showed no distinctive clinical or hematologic features.

Identification of the hairy cells of leukaemic reticuloendotheliosis by an esterase method.

A distinctive pattern of alpha-naphthyl butyrate esterase positivity was observed in all of a series of 14 patients with HCL. This pattern was not observed in a range of other haematological malignancies including nine cases of CLL, two cases of Sézary's syndrome, six cases of null cell ALL, two cases of Schilling-type monocytic leukaemia and one case of lymphosarcoma cell leukaemia. The potential diagnostic value of this simple cytochemical test is discussed in relation to existing methods.

Surface marker and other characteristics of Gaucher's cells.

A full surface marker study of the splenic storage cells in a case of Gaucher's disease largely substantiates the monocyte/histiocyte nature of Gaucher's cells. In addition, an apparent T-lymphocyte deficiency is demonstrated in the spleen and peripheral blood, and the possible significance of this finding is discussed.

Discrimination of B, T and null lymphocytes by esterase cytochemistry.

A technique has been devised which optimally demonstrates non-specific esterase activity in human blood lymphocytes. The reaction is carried out on smears fixed with formalin vapour, using alpha-naphthol butyrate as substrate at pH 8 and at a low concentration for a short incubation period. The pattern of esterase activity revealed by this method provides a discriminating marker for mature T-lymphocytes, which show dense, localised, dot-like positivity, and a probable marker for 'null' cells in the form of scattered granular positivity. B cells appear to be negative. Monocytes show a clearly different pattern of granular positivity.