Comparative Study of Spleen Pathology in Drug Abusers With Thrombocytopenia Related to Human Immunodeficiency Virus Infection and in Patients With Idiopathic Thrombocytopenic Purpura:A Morphometric, Immunohistochemical, and Ultrastructural Study

Abstract

A morphometric and immunohistochemical study was performed to assess the spleen's alterations in patients with autoimmune thrombocytopenia and in drug abusers with thrombocytopenia (DAT) related to human immunodeficiency virus (HIV) infection. A total of 34 patients were included in the study: 20 DAT patients and 14 with idiopathic thrombocytopenic purpura (ITP). Twenty HIV-negative splenectomy patients without thrombocytopenia were included as controls. Spleen weight in DAT patients (323.25 +/- 149.96 g, mean + standard deviation) was significantly increased compared with the ITP (164.28 +/- 29.79 g, P < 0.0001) and control (175.50 +/- 49.14 g, P < 0.0001) groups. The mean diameter of lymphoid follicles in the spleens of DAT patients (446.83 +/- 99.16 microns, was significantly higher than in those of the control patients (370.87 +/- 55.30 microns, P = 0.019). In control patients' spleens, the number of platelets in Billroth's cords was significantly higher (59.54 +/- 32.72/10(4) microns 2) than in those of the DAT (2.13 +/- 1.42/10(4) microns 2, P < 0.0001) and ITP (P < 0.0001) patients. The number of macrophages and ceroid histiocytes per 10(4) microns 2 of red pulp was significantly increased in both DAT (5.14 +/- 1.90) and ITP (7.48 +/- 4.38) patients compared with the control patients (3.66 +/- 1.10, P < 0.0001) and P = 0.06, respectively), and in ITP patients compared with DAT patients (P = 0.0136). The number of granulopoietic precursors per 10(4) microns 2 of red pulp was higher in the spleens of DAT (1.41 +2- 1.46, P < 0.0001) and ITP (0.92 +/- 0.75, P < 0.0001) patients compared with those of the control group. Transmission electron microscopy studies demonstrated platelet phagocytosis by macrophages of Billroth's cords and presence of myeloid metaplasia in spleens of DAT and ITP patients. Immunohistochemical studies showed a depletion of CD4+ lymphocytes in the T zone of splenic white pulp and an increased number of CD8+ lymphocytes in red pulp of DAT patients' spleens compared with those of ITP and control patients. There were no significant alterations in dendritic reticular cell network in the DAT group compared with the ITP and control groups.

Splenic marginal zone atrophy and progressive CD8+ T‐cell lymphocytosis in HIV infection: a study of adult post‐mortem spleens from Côte d'Ivoire

“…Numbers of red pulp phagocytic macrophages also varied widely between cases, correlating neither with splenic weight nor with other features measured. They may be a reflection of malarial infection in these patients, or possibly relate to HIV‐associated destruction of platelets in the spleen 27,28 . Haematological data for our cases (not shown) indicate wide variation in platelet counts which does not correlate with spleen size or content of red pulp macrophages.…”

“…The significance of this intriguing finding is unknown: in other respects, these spleens were indistinguishable from the early HIV infection group. Splenic white pulp follicular hyperplasia has been described in one subset of European HIV+ patients, a group of drug users presenting with a thrombocytopenic syndrome resembling idiopathic thrombocytopenic purpura 27 . These patients were also reported to have a CD8+ lymphocytosis in splenic red pulp and peri‐arteriolar lymphoid sheath, but CD45RO expression was not measured.…”

Hyposplenism from Mycobacterium avium Complex Infection in a Patient with AIDS and Immune Thrombocytopenia

“…Although one can argue that our patient had a delayed response to splenectomy, we postulate that splenic hypofunction secondary to overwhelming MAC infection most likely contributed to the failure of the thrombocytopenia to promptly respond to splenectomy. From a literature search of HIV-related ITP patients who underwent splenectomy, we identified 229 patients [10, 11, 12, 13, 14, 15, 16]. Histology of the spleen was provided in 64 (27.9%) patients and none showed splenic involvement with MAC.…”

The role of neutrophils in antibody-driven autoimmune cytopenias

“…Neutrophils accumulate in the spleen of ITP patients 23,24 , where they represent the vast majority of phagocytic cells. Given that the spleen is the major site of platelet destruction, it is surprising that the contribution of splenic neutrophils in platelet destruction has never been formally addressed.…”