Lymphocyte Subpopulations in Homozygous Sickle Cell Anaemia

Lymphocyte subsets and K cell activity were evaluated in sickle cell anemia (SCA) and in splenec-tomized patients. Results showed that the number of total lymphocytes, T lymphocyte subsets and B lymphocytes were increased in SCA. However, individuals who had undergone splenectomy did not exhibit all these abnormalities, suggesting that the lack of the spleen apparently was not the unique factor responsible for the lymphocyte abnormalities seen in SCA patients.

Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 78%

Are the Changes of Lymphocyte Subsets in Sickle Cell Anemia due to the Loss of Splenic Function?

Donadi

Falcão²

1988

“…In particular, studies of cellular immunity and humoral factors have yielded conflicting results [3, 4]. Also, the few reports of the roles and pattern of cytokines have focused mainly on American patients [15, 16, 17]; studies of Arab patients with the milder disease have not been published.…”

Section: Discussionmentioning

confidence: 99%

“…Studies of neutrophil function and humoral immunity have yielded inconsistent findings [2, 3]. While helper T (CD4+) cells and cytotoxic/suppressor (CD8+) T cells appear to be quantitatively normal in children with the disease, abnormalities have been reported in adult patients [4, 5, 6]. There is abundant evidence that CD4+ and CD8+ cells can be further divided into subsets by their function and pattern of cytokine secretion.…”

Section: Introductionmentioning

confidence: 99%

Th1 and Th2 Cytokine Profiles in Sickle Cell Disease

Haider

Azizieh²,

Abdelsalam

et al. 2000

We have investigated the levels of Th1 (IL-2 and IFN-γ) and Th2 (IL-4) cytokines in the plasma and supernatants following peripheral blood mononuclear cell culture and mitogen stimulation in a group of 39 patients with sickle cell disease (SCD) made up of 29 SS, 8 Sβ-thal and 2 Hb SD in steady state. Five SS patients were studied during 7 episodes of vaso-occlusive crisis. Twenty-four control (3 Hb AS and 21 Hb AA) were also studied; 10 were acutely ill while 14 were healthy at the time of the study. The plasma levels of IL-2 and IFN-γ were similar in the patients and the controls. However, plasma IL-4 was significantly higher among the steady-state SS patients than in the controls. While there was no significant difference in cytokine levels following mitogen stimulation in the different groups, plasma IL-2 to IL-4 and IFN-γ to IL-4 ratios were significantly lower among the steady-state SS patients, indicating a possible Th2 bias in our sickle cell patients and suggesting a possible mechanism to explain the predisposition of SCD patients to bacterial infections. However, SS patients with good splenic function showed a relative Th1 bias, which may be an additional explanation for the protection against bacterial infections in such patients.

“…These re sults might be expected, since high numbers of B lym phocytes [24][25][26][27][28] and a normal percentage of CD4+ T cells [26,27], whose helper activity is required for the antibody response to PWM, have been found in the peripheral blood of patients with SCD. As stated in the Introduction, patients with SS hemoglobinopathy showed a normal production of antibody after anti genic stimulation by the intradermal, subcutaneous, or intramuscular routes [18][19][20], whereas the response to intravenous inoculation of antigen was depressed [9,21].…”

Section: Discussionmentioning

confidence: 99%

In vitro Antibody Synthesis by Peripheral Blood Mononuclear Cells from Patients with Sickle Cell Disease

Malavé

Escalona²,

Perdomo³

et al. 1990

To study the capacity of peripheral blood mononuclear cells (PBMC) from patients with sickle cell disease to synthesize antibodies in vitro, the levels of IgM, IgG, and IgA were quantitated in supernatants of cultured PBMC from a group of asymptomatic adults with sickle cell disease and from normal controls. The rates of spontaneous synthesis of IgM were similar in nonstimulated cultures of PBMC from patients and controls, whereas the amounts of IgG and IgA produced spontaneously by nonstimulated lymphocytes from the patients were significantly greater than those from controls. Similar levels of IgM, IgG, and IgA were detected in the supernatants of cultures stimulated with pokeweed mitogen from patients and controls. Thus, the capacity of PBMC to respond in vitro to pokeweed mitogen was preserved in the patients. The enhanced spontaneous synthesis of IgG and IgA suggests the presence of chronic polyclonal activation of B cells and/or defective regulation of the production of antibodies.