Reduced CD4+ count, infections, and immune thrombocytopenia without HIV infection

Reference ranges of lymphocyte subsets in healthy adults and adolescents with special mention of T cell maturation subsets in adults of South Florida

BACKGROUND

Analysis of peripheral blood lymphocyte subsets has become an essential tool in the evaluation of outcome of diagnostic and research related questions in immunological and pathological conditions. Periodic evaluation and establishment of normal lymphocyte reference ranges are required in clinical and research settings of various immunodeficiency disorders for evaluation of the significance of observations. It is also important that age and gender specific lymphocyte subset reference ranges should be locally established for meaningful comparison and accurate result interpretation as age plays a significant role in the development of immune system.

METHODS

We performed dual platform flow cytometry to determine reference ranges for lymphocyte subsets (CD3, CD4, CD8, CD19 [B cells] and CD16+CD56+ [Natural Killer - NK cells]) in 50 adolescents (age range: 12-18) and 100 adults (age range: 21-67) along with T cell maturation, activation and co-stimulatory molecules in healthy multiracial adult population of South Florida.

RESULTS

The lymphocyte reference ranges percentages [absolute counts - Abs, cells/μl] unadjusted for gender differences for adolescents are: CD3: 49-83 [939-2959]; CD4: 27-53 [467-1563]; CD8: 16-40 [259-1262]; CD19+ B cells: 8-31 [169-1297] and CD16+CD56+ NK cells: 3-30 [59-1178] and for adults are: CD3: 65-88 [983-3572]; CD4: 26-62 [491-2000]; CD8: 14-44 [314-2,087]; CD19+ B cells: 2-27 [64-800] and CD16+CD56+ NK cells: 2-27 [27-693]. The ranges for CD4:CD8 ratio for adolescents and adults are 0.7-2.6 and 0.6-4.4, respectively. Gender based analysis of relative percentages of lymphocyte subsets showed no significant differences between adult and adolescent males and females. The mean CD4:CD8 ratio was significantly higher in adult females than males (P=0.04) and in adolescents this difference was not significant between genders. The mean CD3 and CD4 T cell percentages were higher and CD19 cell percentages were lower in adults compared to adolescents (P<0.0001). Absolute lymphocyte counts showed a positive correlation with the absolute counts of CD3+, CD4+, CD8+, CD19+, CD16+CD56+, CD45RO+ and CD45RA+ cells (all correlations with P<0.0001 except CD45RO [P=0.01] and CD45RA [P=0.03]).

CONCLUSION

The reference values of peripheral blood lymphocyte subsets were analyzed in healthy adolescent and adult population of South Florida. This study indicates the need for periodic evaluation and establishment of lymphocyte reference ranges for patient population served based on gender and age since these could influence immune status and treatment outcome.

Idiopathic CD4 Lymphocytopenia: Spectrum of opportunistic infections, malignancies, and autoimmune diseases

Idiopathic CD4 lymphocytopenia (ICL) was first defined in 1992 by the US Centers for Disease Control and Prevention (CDC) as the repeated presence of a CD4+ T lymphocyte count of fewer than 300 cells per cubic millimeter or of less than 20% of total T cells with no evidence of human immunodeficiency virus (HIV) infection and no condition that might cause depressed CD4 counts. Most of our knowledge about ICL comes from scattered case reports. The aim of this study was to collect comprehensive data from the previously published cases to understand the characteristics of this rare condition. We searched the PubMed database and Science Direct for case reports since 1989 for Idiopathic CD4 lymphocytopenia cases. We found 258 cases diagnosed with ICL in 143 published papers. We collected data about age, sex, pathogens, site of infections, CD4 count, CD8 count, CD4:CD8 ratio, presence of HIV risk factors, malignancies, autoimmune diseases and whether the patients survived or died. The mean age at diagnosis of first opportunistic infection (or ICL if no opportunistic infection reported) was 40.7 ± 19.2 years (standard deviation), with a range of 1 to 85. One-sixty (62%) patients were males, 91 (35.2%) were females, and 7 (2.7%) patients were not identified whether males or females. Risk factors for HIV were documented in 36 (13.9%) patients. The mean initial CD4 count was 142.6 ± 103.9/mm³ (standard deviation). The mean initial CD8 count was 295 ± 273.6/mm³ (standard deviation). The mean initial CD4:CD8 ratio was 0.6 ± 0.7 (standard deviation). The mean lowest CD4 count was 115.4 ± 87.1/mm³ (standard deviation). The majority of patients 226 (87.6%) had at least one infection. Cryptococcal infections were the most prevalent infections in ICL patients (26.6%), followed by mycobacterial infections (17%), candidal infections (16.2%), and VZV infections (13.1%). Malignancies were reported in 47 (18.1%) patients. Autoimmune diseases were reported in 37 (14.2%) patients.

Profound reduction of CD4+ lymphocytes without HIV infection: two cases from the horn of Africa

Idiopathic CD4+ lymphocytopenia is a disorder associated with low CD4+ T cell count and opportunistic infections resembling AIDS. Most cases are described in developed countries. We report two HIV-negative patients with idiopathic CD4+ lymphocytopenia and AIDS-defining events diagnosed in Djibouti. The first patient developed lesions of Kaposi's sarcoma and the second one presented with pulmonary tuberculosis. Both patients died with severe immunodepression. In poor resource-areas where HIV testing may not be available it is important to bear in mind that severe immunodepression and a clinical presentation compatible with AIDS do not necessary carry the diagnosis of AIDS.

Cryptococcosis and idiopathic CD4 lymphocytopenia

We reviewed the cases of 11 patients with cryptococcosis and idiopathic CD4 lymphocytopenia (ICL) referred to our institution in the previous 12 years, as well as 42 similar cases reported in the literature, to assess the characteristics of the infection in this population. Cryptococcosis in 53 patients with ICL had features in common with cryptococcosis in previously normal patients. ICL patients had a slight male predominance (1.2:1) and a median age of presentation of 41 years (range, 4.5-85 yr). Initial cerebrospinal fluid findings showed glucose below 40 mg/dL in 60% of the patients, a median pleocytosis of 59 white blood cells/mm (range, 0-884), and protein of 156 mg/dL (range, 25-402 mg/dL). The median CD4 count at diagnosis of ICL and at the last available measurement was 82 (range, 7-292) and 132 (range, 13-892) cells/mm, respectively, for an average follow-up of 32 months in 46 patients. Unlike previously normal patients with cryptococcosis, those with ICL had an excess incidence of dermatomal zoster (7 episodes in 46 ICL cases). Pneumocystis pneumonia was rare (1 case), casting doubt on the need for prophylaxis in patients with ICL. A favorable outcome (cured or improved) may be more common in ICL patients than in previously normal patients with cryptococcal meningitis and no predisposing factors. Identification of ICL in patients who were apparently normal before the onset of cryptococcosis appears to be useful because it predicts a favorable outcome. Patients with cryptococcal infection and ICL have an increased likelihood of developing dermatomal zoster. The long-term follow-up of these patients offers some reassurance regarding favorable prognosis.

Lymphocytopenia in a hospital population--what does it signify?

BACKGROUND

Lymphocytopenia is a common finding in hospital patients especially since the advent of automated differential leukocyte counters. The causes and significance of lymphocytopenia are generally poorly understood. There has been no large-scale study of its significance for 25 years. The HIV epidemic, and the recently described idiopathic CD4+ T-lymphocytopenia have raised interest in this finding.

AIMS

To describe the spectrum of lymphocytopenia in an adult teaching hospital and investigate its clinical significance.

METHODS

Using the available computer facilities, patients with significant lymphocytopenia (< 0.6 x 10(9)/L) were identified over a 102 day period and diagnoses, operations and medication lists obtained. Where necessary, patient histories were examined to supplement the above information. If feasible, previous and subsequent lymphocyte counts were checked to establish if the lymphocytopenia were temporary or longstanding.

RESULTS

One thousand and forty-two patients were identified, with a mean age of 59.6 years, of whom 563 were male, and 757 were inpatients. Thirty-six patients were pancytopenic. We checked previous and subsequent counts for 698 patients and found 45 patients who were consistently lymphocytopenic, some for more than ten years. Thirty-four patients with previously normal counts remained lymphocytopenic throughout follow up, while 457 had at least one subsequent lymphocyte count > 1 x 10(9)/L. We found only one patient who was suspected of having idiopathic CD4+ T-lymphocytopenia. Patients fell into several categories (with some overlap): bacterial/fungal sepsis (250), post-operative (228), corticosteroid therapy (definite 159, suspected 53, inhaled steroids alone 14), malignancy (174 definite, six probable), cytotoxic therapy and/or radiotherapy (90), trauma or haemorrhage (86), transplants (73-38 renal and 35 bone marrow), 'viral infections' (26) and HIV infection (13). Thirty-four patients died within the study period.

CONCLUSIONS

Lymphocytopenia in hospital patients is most frequently reversible, and due to acute illness, notably sepsis and trauma (including surgery). Malignancy, with or without chemotherapy, and steroid use are also common causes, but HIV infection is a relatively uncommon cause in our hospital.

Antibodies against retroviral proteins and nuclear antigens in a subset of idiopathic CD4+ T lymphocytopenia patients

Idiopathic CD4+ T lymphocytopenia (ICL) is an immunodeficiency syndrome characterized by severe depletion of CD4+ T lymphocytes, but in which human immunodeficiency virus cannot be detected. Peripheral blood mononuclear cells (BPMCs) from an ICL patient were cocultured with HUT78 T-lymphoblastoid cells, and an acute cytopathic effect and formation of multinucleated cells were observed. A human intracisternal A-type retroviral particle designated HIAP-II was detected in cells surviving the acute cytopathic effect. Eight of 13 ICL patients in a blinded screen of a serological panel provided by the National Centers for Disease Control and Prevention (CDC) had serum antibodies that specifically reacted with HIAP-II associated proteins by Western immunoblotting. None of 19 control sera in the panel that were unreactive with HIV Gag proteins produced a positive result on HIAP-II immunoblots. Comparable results were obtained in a blinded screen of a second CDC serological panel. Sera from 8 of 14 ICL patients in the second serological panel were positive for antinuclear autoantibodies (ANAs) commonly observed in patients with systemic autoimmune diseases. These results suggest the possible involvement of an A-type retrovirus or autoimmunity in development of ICL in a subset of patients.

Protracted cutaneous disorders in association with low CD4+ lymphocyte counts

We report two patients with skin disorders usually associated with severe immunosuppression, who had low CD4+ lymphocyte counts but normal immunoglobulin levels. The patients were HIV negative, and had CD4+ lymphocyte counts just above 300/mm3, but they presented with cutaneous manifestations of profound immunodeficiency. Idiopathic CD4+ lymphocyte deficiency is a recently described syndrome which may present with dermatological disease. We discuss the symptom complex of our patients in relationship to the diagnosis of idiopathic CD4+ lymphocyte deficiency.

CD4 similarity to proteins of infectious agents in AIDS and their role in autoimmunity

Lymphocytotoxic autoimmunity (LA) is ubiquitous in AIDS. Its causes are unknown. We report that significant amino acid sequence similarities exist between the proteins of infectious organisms associated with AIDS and the CD4 protein of T-helper lymphocytes. These included: HIV, cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex viruses (HSV), Varicella Zoster virus (VZV), Escherichia coli, Mycobacteria, Mycoplasmas, Plasmodium, and Staphylococcus. It has been reported previously that HIV proteins have significant similarities with human class II MHC (HLA class II) proteins. Since CD4 and HLA class II proteins are chemically complementary, pairs of homologous antigens will also be complementary. It follows that concurrent infections with CD4 and HLA class II-homologous antigens will result in idiotype-antiidiotype antibody pairs that cannot distinguish 'self' from 'nonself', that acts as lymphocytotoxins, and form circulating immune complexes. Thus, combined HIV-CMV, HIV-EBV, HIV-HBV, HIV-mycoplasma, or other appropriate infectious pairs may suffice to trigger LA in AIDS.

Idiopathic CD4+ lymphocytopenia associated with chronic pruritic papules

This is a case report and family study of a 65-year-old man with chronic prurigo lesions, in whom we demonstrated a selective deficiency of circulating T-helper/inducer lymphocytes (CD4+), in the absence of any apparent predisposing disease. He is seronegative for human immunodeficiency virus (HIV types 1 and 2) and human T-cell lymphotropic virus (HTLV-I and HTLV-II), and fulfils the criteria for the syndrome of idiopathic CD4+ T lymphocytopenia. He has an atopic diathesis, has had a severe adult chickenpox infection, chronic staphylococcal infections, tinea pedis and recalcitrant warts. He has also suffered from respiratory infections, for which no specific aetiological agent has been identified. His peripheral total lymphocyte count has been persistently abnormal since it was first measured in 1969. He has a marked CD4+ T-cell lymphocytopenia. His son, who does not have any skin disorder, has a low CD4+ T-cell count.

Idiopathic CD4+ T-lymphocytopenia--an analysis of five patients with unexplained opportunistic infections

BACKGROUND

Although patients with idiopathic CD4+ T-lymphocytopenia and serious opportunistic infections have been described previously, the clinical and immunologic features of this condition have not been well defined.

METHODS

We studied in detail five patients with idiopathic CD4+ T-lymphocytopenia. The studies included serologic testing, culture, and polymerase chain reaction for the human immunodeficiency virus (HIV) types 1 and 2, serologic testing for the human T-cell lymphotropic virus (HTLV) types I and II, lymphocyte phenotyping, immunoglobulin quantitation, and lymphocyte-transformation assays, as well as attempts to isolate a retroviral agent. The results were compared with those in HIV-infected persons matched for CD4+ T-cell counts and with those in normal controls. We also studied the spouses of patients and the blood donors for one patient.

RESULTS

In these five patients, there was no evidence of either HIV or HTLV infection. All the patients had both low percentages and low counts of CD4+ T cells, with relative increases in percentages, but not counts, of CD8+ cells. Numbers of B cells and natural killer cells were generally normal. As compared with HIV-infected persons, our patients had lower percentages and counts of CD8+ cells and more lymphopenia. CD4+ counts were relatively stable over time. Instead of the high immunoglobulin levels seen in HIV infection, these patients had normal or slightly low levels of immunoglobulins. The lymphocyte-transformation response to mitogens and antigens was depressed. Results in spouses and blood donors were normal.

CONCLUSIONS

Idiopathic CD4+ T-lymphocytopenia differs from HIV infection in its immunologic characteristics and in its apparent lack of progression over time. Nothing about the immunologic or viral-culture studies performed in these patients or about their family members or blood donors suggests that a transmissible agent causes this condition.

Unexplained opportunistic infections and CD4+ T-lymphocytopenia without HIV infection. An investigation of cases in the United States. The Centers for Disease Control Idiopathic CD4+ T-lymphocytopenia Task Force

BACKGROUND

The clinical and public health importance of recent reports of patients with CD4+ T-lymphocytopenia without human immunodeficiency virus (HIV) infection is unclear. We conducted investigations to determine the demographic, clinical, and immunologic features of patients with idiopathic CD4+ T-lymphocytopenia; whether the syndrome is epidemic or transmissible; and the possible causes.

METHODS

We reviewed 230,179 cases in the Centers for Disease Control and Prevention (CDC) AIDS Reporting System and performed interviews, medical-record reviews, and laboratory analyses of blood specimens from adults and adolescents who met the CDC case definition of idiopathic CD4+ T-lymphocytopenia (< 300 CD4+ cells per cubic millimeter or a CD4+ cell count < 20 percent of total T cells on two occasions and no evidence of infection on HIV testing), their sexual contacts, household contacts, and persons who had donated blood to them.

RESULTS

We interviewed 31 of the 47 patients identified with idiopathic CD4+ T-lymphocytopenia and 23 of their contacts. There were 29 male and 18 female patients, with a mean age of 43 years (range, 17 to 78); 39 were white, 4 were Asian, 2 were Hispanic, and 2 were black. Eighteen patients (38 percent) had one or more risk factors for HIV infection: seven had hemophilia, six had engaged in homosexual sex, six had received blood transfusions, and two had had heterosexual sex partners who were at risk for HIV infection. The other 29 patients (62 percent) had no identified risk factors for HIV infection. Nineteen persons (40 percent) had AIDS-defining illnesses (18 had opportunistic infections), 25 (53 percent) had conditions that were not AIDS-defining, and 3 (6 percent) were asymptomatic. We tested blood from 28 patients: 8 (29 percent) were found to have CD4+ T-lymphocyte counts of less than 300 cells per cubic millimeter, and 6 had CD8+ T-lymphocytopenia (< 250 cells per cubic millimeter). Ten sex partners, three household contacts, and four children of the patients, as well as six persons who had donated blood to the patients, were immunologically and clinically normal.

CONCLUSIONS

This investigation of patients with idiopathic CD4+ T-lymphocytopenia and unexplained opportunistic infections indicates that the disorder is rare and represents various clinical and immunologic states. The investigation of contacts revealed no evidence of a new transmissible agent that causes lymphocytopenia.

Idiopathic CD4+ T-lymphocytopenia--four patients with opportunistic infections and no evidence of HIV infection

BACKGROUND AND METHODS

We describe four patients without major risk factors for human immunodeficiency virus (HIV) infection, each of whom presented with severe opportunistic infections and was found to have idiopathic CD4+ T-lymphocytopenia. We performed assays to detect the presence of retroviruses and undertook immunophenotyping of subgroups of peripheral-blood lymphocytes.

RESULTS

The opportunistic infections at presentation included Pneumocystis carinii pneumonia, cryptococcal meningitis (two patients, one with concurrent pulmonary tuberculosis), and histoplasma-induced brain abscess. During 10 to 68 months of observation, none of the four patients had evidence of infection with HIV type 1 or 2 or human T-cell lymphotropic virus type I or II on the basis of epidemiologic, serologic, or polymerase-chain-reaction studies or culture, nor was there any detectable reverse transcriptase activity. Although all the patients had severe, persistent CD4+ T-lymphocytopenia (range, 12 to 293 cells per cubic millimeter), the CD4+ cell count progressively declined in only one and was accompanied by multiple opportunistic infections. All four patients had significantly reduced numbers of circulating CD8+ T cells, natural killer cells, or B cells (or all three).

CONCLUSIONS

These four patients had idiopathic CD4+ T-lymphocytopenia with opportunistic infections but no evidence of HIV infection. Instead of the progressive, selective depletion of CD4+ T cells characteristic of HIV infection, some patients with idiopathic immunodeficiency have stable CD4+ cell counts accompanied by reductions in the levels of several other lymphocyte subgroups.