       Document 0922
 DOCN  M9540922
 TI    Pathophysiology of HIV related thrombocytopenia: an analysis of 41
       patients.
 DT    9504
 AU    Dominguez A; Gamallo G; Garcia R; Lopez-Pastor A; Pena JM; Vazquez JJ;
       Department of Internal Medicine, La Paz Hospital, Madrid, Spain.
 SO    J Clin Pathol. 1994 Nov;47(11):999-1003. Unique Identifier : AIDSLINE
       MED/95130768
 AB    AIM--To analyse the pathogenic mechanism of HIV related
       thrombocytopenia. METHODS--Forty one patients with thrombocytopenia and
       HIV-1 infection were investigated over two years. Anticardiolipin
       antibodies were measured using an enzyme linked immunosorbent assay and
       antiplatelet antibodies were measured using an immunocapture technique.
       Tests for VDRL, C3 and C4, antinuclear antibodies and rheumatoid factor
       were also carried out in all patients and 80 control subjects (HIV-1
       positive but non-thrombocytopenic). Indiumoxine labelled platelets were
       transfused in 13 patients. P24 antigen were also measured in 12 bone
       marrow aspirates. RESULTS--Antiplatelet antibodies and circulating
       immune complexes were found exclusively in the thrombocytopenic group;
       values for antiplatelet antibodies and circulating immune complexes were
       both higher in homosexual and bisexual patients. Three kinds of pattern
       were observed using 111 In-labelled platelets: splenic (n = 10); hepatic
       (n = 2); and destruction of bone marrow in just one case. The two most
       influential factors in the sequestration pattern were antiplatelet
       antibodies in the splenic uptake and circulating immune complexes in the
       hepatic and marrow sequestration. All patients, except three, had
       decreased platelet recovery. In those patients with a CD4 lymphocyte
       count of less than 200 x 10(6) cells/l the recovery was clearly greater
       (53%) than in patients who had more than 200 x 10(6) /l (28%). Finally,
       in seven of the 12 patients who were chosen for immunohistochemical
       study, p24 antigen was detected in the megakaryocytes, verifying that
       HIV-1 infects such cells. CONCLUSIONS--The pathogenic mechanism of HIV
       related thrombocytopenia is probably multifaceted. Antiplatelet
       antibodies and circulating immune complexes would cause peripheral
       destruction in the spleen, liver, and bone marrow, in that order; and,
       on the other hand, there would be an ineffective immune thrombopoiesis
       and direct infection of the megakaryocytes which could cause a change in
       the function and maturity of these cells.
 DE    Antigen-Antibody Complex/*BLOOD  Autoantibodies/*BLOOD  Bisexuality
       Blood Platelets/*IMMUNOLOGY  Female  Homosexuality  Human  HIV Core
       Protein p24/ANALYSIS  HIV Infections/*COMPLICATIONS/IMMUNOLOGY/PATHOLOGY
       *HIV-1  Immunohistochemistry  Male  Megakaryocytes/CHEMISTRY
       Thrombocytopenia/IMMUNOLOGY/*VIROLOGY  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

