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

Reappraisal of Idiopathic CD4 Lymphocytopenia at 30 Years

BACKGROUND

Idiopathic CD4 lymphocytopenia (ICL) is a clinical syndrome that is defined by CD4 lymphopenia of less than 300 cells per cubic millimeter in the absence of any primary or acquired cause of immunodeficiency. Some 30 years after its original identification, ICL has remained a disease of obscure cause, with limited evidence with respect to its prognosis or management, despite diagnostic and therapeutic innovations.

METHODS

We evaluated the clinical, genetic, immunologic, and prognostic characteristics of 108 patients who were enrolled during an 11-year period. We performed whole-exome and targeted gene sequencing to identify genetic causes of lymphopenia. We also performed longitudinal linear mixed-model analyses of T-cell count trajectories and evaluated predictors of clinical events, the response to immunization against coronavirus disease 2019 (Covid-19), and mortality.

RESULTS

After the exclusion of patients with genetic and acquired causes of CD4 lymphopenia, the study population included 91 patients with ICL during 374 person-years of follow-up. The median CD4+ T-cell count among the patients was 80 cells per cubic millimeter. The most prevalent opportunistic infections were diseases related to human papillomavirus (in 29%), cryptococcosis (in 24%), molluscum contagiosum (in 9%), and nontuberculous mycobacterial diseases (in 5%). A reduced CD4 count (<100 cells per cubic millimeter), as compared with a CD4 count of 101 to 300 cells, was associated with a higher risk of opportunistic infection (odds ratio, 5.3; 95% confidence interval [CI], 2.8 to 10.7) and invasive cancer (odds ratio, 2.1; 95% CI, 1.1 to 4.3) and a lower risk of autoimmunity (odds ratio, 0.5; 95% CI, 0.2 to 0.9). The risk of death was similar to that in the age- and sex-adjusted general population, but the prevalence of cancer was higher.

CONCLUSIONS

Among the study patients, ICL continued to be associated with increased susceptibility to viral, encapsulated fungal, and mycobacterial diseases, as well as with a reduced response to novel antigens and an increased risk of cancer. (Funded by the National Institute of Allergy and Infectious Diseases and the National Cancer Institute; ClinicalTrials.gov number, NCT00867269.).

Childhood-onset Takayasu arteritis and immunodeficiency: case-based review

Takayasu arteritis (TAK) has been rarely reported in patients with immunodeficiency. In this review, we present two cases with childhood-onset TAK (c-TAK) and primary immunodeficiency while reviewing similar cases in the literature. We reviewed the data for our two pediatric patients with c-TAK and primary immunodeficiency. We also reviewed the literature for patients with c-TAK and immunodeficiency from the inceptions of the databases up to November 2021. A 14-year-old patient had lipopolysaccharide-sensitive beige-like anchor (LRBA) deficiency, and a 16-year-old had X-linked severe combined immunodeficiency (X-linked SCID). During the follow-up, they developed findings suggestive of vasculitides such as hypertension, elevation in acute phase reactants, weakness, and weight loss. Thoracoabdominal computed tomography angiography revealed findings consistent with vasculitis involving the aorta and its major branches. Patients were diagnosed with c-TAK, and corticosteroids were given to both patients in the treatment. We identified 11 articles describing 17 TAK patients with immunodeficiency in our literature search. Two of the patients with c-TAK were infected with human immunodeficiency virus (HIV), another patient had Wiskott-Aldrich syndrome, and the other had idiopathic CD4 + T lymphocytopenia. Nine adult patients with TAK were infected with HIV, three patients had common variable immunodeficiency disorder (CVID), and the other had STAT1 gain-of-function mutation. Clinicians should consider that immunodeficiencies may be accompanied by vasculitic conditions such as TAK. Hypertension, increased inflammatory markers, and constitutional symptoms may be red flags for the development of TAK.

Characterization of autoantibodies, immunophenotype and autoimmune disease in a prospective cohort of patients with idiopathic CD4 lymphocytopenia

OBJECTIVE

Characterize autoantibodies and autoimmune diseases in a prospective cohort of patients with Idiopathic CD4 Lymphocytopenia (ICL) a rare immunodeficiency characterized by an absolute CD4⁺ T count of <300 cells/μl in the absence of HIV or HTLV infection.

METHODS

Single-Center prospective study of 67 patients conducted over an 11-year period. Rheumatologic evaluation and measurement of autoantibodies were systematically conducted, and flow cytometry of immune cell subsets was performed in a subset of patients.

RESULTS

54% of referred patients had clinical evidence of autoimmunity, with 34% having at least one autoimmune disease, most commonly autoimmune thyroid disease. 19%, had autoantibodies or incomplete features of autoimmune disease. Patients with autoimmune disease had more elevated serum immunoglobulins, and more effector memory T cells than those without autoimmunity.

CONCLUSIONS

Evidence of autoimmunity, including autoimmune diseases, is more prevalent in ICL than the general population, and should be considered part of this syndrome.

Idiopathic CD4 lymphocytopenia: Pathogenesis, etiologies, clinical presentations and treatment strategies

BACKGROUND

Idiopathic CD4 lymphocytopenia (ICL) is a rare condition characterized by an unexplained deficit of circulating CD4 T cells leading to increased risk of serious opportunistic infections. The pathogenesis, etiology, clinical presentation, and best treatment options remain unclear.

OBJECTIVE

To describe the clinical presentation, treatment strategies, and outcome of patients with ICL seen in a single referral center.

METHODS

In a retrospective study, from January 1993 to January 2014, the demographic characteristics, clinical presentation, and treatments of patients diagnosed with ICL were reviewed.

RESULTS

Twenty-four patients (14 female [58%] and 10 male [42%]) were evaluated. The mean age was 45 ± 17.6 years (range 7-76 years). Mean CD4 and CD8 T-cell counts at the time of diagnosis were 119 ± 84/mm³ (range 4-294/mm³) and 219 ± 258/mm³ (range 7-630/mm³), respectively. Seventeen patients (71%) had opportunistic infections, 4 (17%) had malignancies, and 3 (13%) had unexplained demyelinating disease and neurologic problems. Most patients had normal levels of immunoglobulins. Thirteen patients had abnormally low to absent response to phytohemagglutinin, concanavalin A, and antigens (candida and tetanus). Three patients had resolution of warts and 1 had mycobacterial lung infection on interleukin-2 with increases in CD4 count. The 11 patients on trimethoprim and sulfamethoxazole had no further hospital admissions for infections.

CONCLUSION

The pathogenesis of ICL remains unclear. Although only some patients are healthy, most patients present with opportunistic infections. There is no known standard treatment aside from prophylactic antibiotics.

Rapid Fatal Outcome of Cryptococcal Meningoencephalitis in a Non-HIV Immunocompromised Patient with a Low Fluconazole Susceptibility Isolate: A Case Report from Madagascar

Cryptococcal meningoencephalitis is considered rare in HIV-negative individuals. In Madagascar, the epidemiology of cryptococcosis has not yet been well described, neither in immunocompetent nor in immunocompromised patients. We report here the first Malagasy detailed case of cryptococcal meningoencephalitis in a non-HIV immunocompromised adult patient carrying a low fluconazole susceptibility isolate. We emphasize the importance of early and accurate diagnosis to meet the challenges of managing cryptococcosis in developing countries.

Idiopathic CD4 lymphocytopenia with sensorimotor polyneuropathy

A, 21-years-old, male, presented with acute onset, gradually progressive, predominantly distal, symmetrical weakness of both upper and lower limbs with arreflexia. He had impaired sensations in glove and stocking distribution with distal gradient. He was found to have absolute CD4 + cell count of 188 cells/μL, absolute CD8 cell count, 532 cells/μL and CD4: CD8 ratio of 0.35. Electrophysiology revealed reduced to absent CMAP amplitude as well as SNAPs in various nerves of upper and lower limbs, along with normal conduction velocity and normal F wave latencies. Pattern evoked visual potentials were prolonged, on both sides, P100 being 130 ms, on right and 108 ms, on left side. In the follow up of 2 years, he showed spontaneous but gradual clinical improvement but his electrophysiological parameters as well as CD 4+ cells count did not show any significant improvement.

Idiopathic lymphocytopenia

PURPOSE OF REVIEW

Idiopathic CD4⁺ lymphocytopenia (ICL) is defined by the reduction of the main lymphocyte subtype in peripheral blood and CD4⁺ T cells below 300/μl in the absence of any secondary known causes of lymphopenia, including viral causes. The present review aims to state the latest available data on clinical, pathological and therapeutic aspects related to ICL, published from 1990 to 2014. The last observed clinical presentation and complications of ICL patients are described. The latest findings and possible mechanisms involved in the development of ICL features are included in the present review; however, pathogenesis of ICL has remained mainly obscured. Finally, recent therapeutic efforts considered in ICL patients are discussed.

RECENT FINDINGS

In spite of the serious complications ICL has on the patients' quality of life, data on clinical, etiopathological and therapeutic behavior for ICL are very limited. On one side, an abnormal blood cell count may be the sole presentation; however, occurrence of disseminated malignant tumors is not uncommon in patients. Recent findings highlight the role of cytokines, especially interleukin-2, on features such as phenotype severity and responsiveness of the condition to therapy. In addition, some studies have suggested that a defect in hematopoietic stem cells may be involved in disease progression, an idea that is supported by the success of bone marrow transplantation in acquiring persistent remissions in ICL patients.

SUMMARY

ICL is a hematologic condition of increasing importance due to its diverse clinical and pathological spectrum. Molecular studies have shown the presence of mutations involved in lymphocyte development as potential factors that may contribute to ICL occurrence. ICL patients could present either with common infections or really serious malignant conditions. The role of cytokines, especially interleukin-2, has emerged as one of the main possible mechanisms involved in clinical and pathological behavior of ICL. Today, the main therapeutic approaches are controlling life-threatening infections and underlying disorders along with efforts to cure ICL through rising CD4⁺ cell counts using cytokine interventions and transplantation.

Idiopathic CD4 lymphocytopenia: clinical and immunologic characteristics and follow-up of 40 patients

Idiopathic CD4 T lymphocytopenia (ICL) is a rare and severe condition with limited available data. We conducted a French multicenter study to analyze the clinical and immunologic characteristics of a cohort of patients with ICL according to the Centers for Disease Control criteria.We recruited 40 patients (24 female) of mean age 44.2 ± 12.2 (19-70) years. Patients underwent T-lymphocyte phenotyping and lymphoproliferation assay at diagnosis, and experiments related to thymic function and interferon (IFN)-γ release by natural killer (NK) cell were performed. Mean follow-up was 6.9 ± 6.7 (0.14-24.3) years. Infectious, autoimmune, and neoplastic events were recorded, as were outcomes of interleukin 2 therapy.In all, 25 patients had opportunistic infections (12 with human papillomavirus infection), 14 had autoimmune symptoms, 5 had malignancies, and 8 had mild or no symptoms. At the time of diagnosis, the mean cell counts were as follows: mean CD4 cell count: 127/mm (range, 4-294); mean CD8: 236/mm (range, 1-1293); mean CD19: 113/mm (range, 3-547); and mean NK cell count: 122/mm (range, 5-416). Most patients had deficiency in CD8, CD19, and/or NK cells. Cytotoxic function of NK cells was normal, and patients with infections had a significantly lower NK cell count than those without (p = 0.01). Patients with autoimmune manifestations had increased CD8 T-cell count. Proliferation of thymic precursors, as assessed by T-cell rearrangement excision circles, was increased. Six patients died (15%). CD4 T-cell count <150/mm and NK cell count <100/mm were predictors of death.In conclusion, ICL is a heterogeneous disorder often associated with deficiencies in CD8, CD19, and/or NK cells. Long-term prognosis may be related to initial CD4 and NK cell deficiency.

Kikuchi-Fujimoto Disease Associated with Symptomatic CD4 Lymphocytopenia

Kikuchi-Fujimoto disease is a rare benign condition of necrotising histiocytic lymphadenitis with unknown aetiology. We describe here a 30-year-old African American female who presented with fever, generalized rash, cervical lymphadenopathy, and oral candidiasis and was found to have Kikuchi-Fujimoto disease on lymph node biopsy with low CD4 count. The initial presentation was concerning for acute retroviral infection. Her HIV serology and HIV RNA PCR were negative however she had low CD4 count with reversal of CD4/CD8 ratio. Although low CD4 count has been associated with autoimmune disease, it has not been described with Kikuchi-Fujimoto disease. We report the first case of Kikuchi-Fujimoto disease associated with symptomatic CD4 lymphocytopenia.

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.

Consequences of a mutation in the UNC119 gene for T cell function in idiopathic CD4 lymphopenia

The activation of a T cell through T cell receptor (TCR) is fundamental to adaptive immune responses. The lymphocyte specific kinase (LCK) plays a central role in the initiation of signaling from the TCR. TCR activates LCK through the adaptor protein uncoordinated 119 (UNC119). A mutation of human UNC119 impairs LCK activation and is associated with inadequate signaling, diminished T cell responses to TCR stimulation, CD4 lymphopenia, and infections of viral, bacterial, and fungal origin. The above clinical and immunological findings meet the criteria of the idiopathic CD4 lymphopenia (ICL). The discovery of the UNC119 defect provides a molecular mechanism for a subset of patients with this previously unexplained disease. Here we review our recent findings on the UNC119 mutation in ICL.

Fatal histoplasmosis in a non-HIV patient in French Guiana

Histoplasmosis is an endemic fungal infection that causes no symptoms or minor self-limited illnesses in most cases. Severe forms are commonly reported in patients with immunodeficiency disorders; histoplasmosis is considered to be an opportunistic infection in patients with AIDS. We report a case of disseminated histoplasmosis in a patient with no induced active suppression of the immune response. The infection was fulminant, and antifungal treatment was delayed because of a misdiagnosis of tuberculosis.

[Dysfunctions of the CXCL12 (SDF-1)/CXCR4 signaling axis in the WHIM syndrome and the idiopathic CD4(+) T-cell lymphocytopenia]

Chemokines are small cytokine-like secreted proteins that govern migration of leukocytes to their specific niches in lymphoid organs and to inflammatory sites. They mediate their functions by binding to and activating chemokine receptors, which belong to the heptahelical G protein-coupled receptor family. The CXC chemokine Stromal cell Derived Factor-1 (SDF-1/CXCL12) is the sole natural ligand for the broadly expressed CXCR4 receptor and acts as a chemoattractant for many leukocyte subsets. The CXCL12/CXCR4 axis exerts critical activities in homeostatic processes such as organogenesis, hematopoiesis and leukocyte trafficking. Dysregulations of CXCR4 signaling and/or expression are associated with several infectious, inflammatory, autoimmune and malignant conditions. In light of recent data, we review here CXCR4 dysfunctions unveiled in two rare human immunodeficiency disorders, one characterized by a gain of CXCR4 function, the WHIM syndrome, and the other by a loss of CXCR4 function, the idiopathic CD4(+) T-cell lymphocytopenia.

Idiopathic CD4 lymphocytopenia presenting as refractory cryptococcal meningitis

Idiopathic CD4 T-lymphocytopenia (ICL) is a syndrome characterized by depletion of CD4 T-cells without evidence of human immunodeficiency virus (HIV) infection. There are a few reported cases of ICL associated with different diseases and clinical conditions, most commonly the opportunistic infections like Tuberculosis, fungal and parasitic diseases which are also seen in HIV-positive patients. We report a case without risk factors or laboratory evidence of HIV infection who presented with refractory cryptococcal meningitis and was found to have ICL.

Idiopathic CD4+ T-cell lymphocytopenia is associated with impaired membrane expression of the chemokine receptor CXCR4

Idiopathic CD4(+) T-cell lymphocytopenia (ICL) is a rare acquired T-cell immunodeficiency of unknown pathogenic basis. Six adults with ICL who developed opportunistic infections were investigated using extensive immunophenotyping analysis and functional evaluation of the chemokine receptor CXCR4. For all 6 patients studied, a profound defect in CXCR4 expression was detected at the surface of CD4(+) T lymphocytes, in association with an abnormal intracellular accumulation of CXCR4 and of its natural ligand, the chemokine CXCL12. For all patients studied, CD4(+) T-cell chemotactic response toward CXCL12 was decreased, whereas sensitivity to CXCL8 was preserved. CXCR4 recovery after ligand-induced endocytosis was impaired in ICL CD4(+) T cells. Upon in vitro addition of interleukin-2 (IL-2), membrane expression of CXCR4 returned to normal levels in 5 of 6 patients, whereas intracellular accumulation of CXCR4 and CXCL12 disappeared. Upon therapeutic administration of IL-2, CD4(+) T-cell count and membrane CXCR4 expression and function improved over time in 3 of 4 patients treated. Therefore, our data indicate that ICL is associated with defective surface expression of CXCR4, which may be reversed by IL-2.

Safety and efficacy of treatment using interleukin-2 in a patient with idiopathic CD4(+) lymphopenia and Mycobacterium avium-intracellulare

We present the case of a 39-year-old white man with a Myobacterium avium-intracellulare pulmonary infection found to have a CD4(+) count of 172 cells/mm(3) and diagnosed subsequently with idiopathic CD4(+) lymphopenia (ICL). After receiving clathromycin for 4 months with minimal improvement, the patient was started on pegylated subcutaneous interleukin (IL)-2 at 600,000 units daily. Later, he received incrementally higher pegylated IL-2 doses until he reached a maintenance dose 3 months later of 11 million units weekly divided into three equal doses. After 5 months of therapy, the patient's chronic cough resolved completely, sputum cultures became negative for Myobacterium avium-intracellulare and the CD4(+) T cell count increased to 553 cells/mm(3). After 35 months of well-tolerated IL-2 treatments and no recurrence of any opportunistic infections, IL-2 treatment was stopped. CD4(+) counts 6 and 9 months after discontinuing IL-2 treatment were 596 and 378 cells/mm(3) respectively, and he remains asymptomatic. This report supports IL-2 treatment for ICL-associated opportunistic infections as a safe and potentially efficacious treatment option, especially when combined with more traditional treatment regimens.

EBV(+) B-cell lymphoproliferative disorder associated with subsequent development of Burkitt lymphoma in a patient with idiopathic CD4(+) T-lymphocytopenia

We report here a case of idiopathic CD4(+) T-lymphocytopenia (ICL) associated with Epstein-Barr virus (EBV)(+) lymphoproliferative disorder (LPD) terminating in Burkitt lymphoma (BL). A 33-year-old Japanese male was admitted to the hospital showing severe CD4(+) lymphocytopenia and neutropenia that was diagnosed as ICL in 1993. Twenty months after the onset of disease, right cervical lymphadenopathy was detected. Biopsy of the specimen showed reactive lymph node hyperplasia and interfollicular B-cell hyperplasia. Ninety-one months later, polypoid tumors were resected from the bilateral nasal cavities and were diagnosed as BL. Immunohistological studies suggested the reactive nature of the initial lymph node biopsy specimen. Polymerase chain reaction (PCR) analyses of immunoglobulin heavy-chain gene (IgH) demonstrated a polyclonal pattern in the initial lymph node lesion. However, the subsequent BL demonstrated a clonal band in the PCR assay for the IgH gene. As demonstrated in human immunodeficiency virus (HIV)-patients, clonal expansion of EBV infected B-cells in the initial lymph node lesion may progress to BL in this patient. The present case did not associate with severe opportunistic infections during the course of disease. EBV(+) BL may be the first manifestation of severe immunodeficiency of the ICL in this patient.

Idiopathic CD4+ T-cell lymphocytopenia

Idiopathic CD4+ T lymphocytopenia (ICL) is an unusual immune defect in which there is an unexplained deficit of CD4+ T cells, leading to serious opportunistic infections. In view of the rarity of this clinical entity, we report two cases of ICL who presented with low CD4+ count or percentage and various opportunistic infections like candida, cytomegalovirus, Mycobacterium tuberculosis.

Multiple immune abnormalities in a patient with idiopathic CD4+ T-lymphocytopenia

Idiopathic CD4+ T-lymphocytopenia (ICL) is a new disease entity characterized by CD4+ T-lymphocyte depletion without evidence of HIV infection. We report a 27-year-old ICL patient with a long history of multiple immune abnormalities. His CD4+ T-lymphocyte count started to decrease after generalized lymphadenopathy of an unknown cause at age 3. He satisfied the criteria for ICL at age 9, and the decreased CD4+ T-lymphocyte count persisted for more than 18 years. This is probably the first childhood-onset ICL case in which the trigger event for the development was known together with the patient's autoimmune background.

CD4 immunophenotyping in HIV infection

The ability to rapidly identify immune cell subsets such as CD4 cells, which became possible around the same time as the onset of the HIV/AIDS pandemic, was one of the greatest advances in clinical and diagnostic immunology. The evolution of this global pandemic and the subsequent development of treatment strategies to prolong the life of infected individuals mean that it is now more crucial than ever that we develop affordable, reliable and accurate methods for the enumeration of CD4 cells. Here, we provide an overview of the historical developments in CD4 enumeration technologies that are related to HIV infection, and summarize the current technological challenges that must be overcome to meet the needs of those living with HIV infection.

Lymphopenia associated with adjuvant anthracycline/ taxane regimens

BACKGROUND

We observed 2 cases of Pneumocystis carinii pneumonia (PCP) occurring in HIV-negative patients during treatment with dose-dense chemotherapy with doxorubicin/cyclophosphamide (AC) followed by paclitaxel (T). These represent the first case reports of PCP occurring during dose-dense chemotherapy for breast cancer. Because lymphocyte depletion is thought to predispose patients to PCP, we explored whether the shortened intervals between cycles during dose-dense chemotherapy might place patients at risk for lymphocyte depletion and thereby a potentially increased risk of opportunistic infection.

PATIENTS AND METHODS

Three cohorts of patients were analyzed. Cohort 1 involved 135 patients receiving dose-dense AC --> T on a phase II study. Cohort 2 included 64 patients who received treatment with dose-dense AC --> albumin-bound paclitaxel on a phase II clinical trial. Cohort 3 consisted of 59 patients who received AC --> T given every 3 weeks who were identified from the Clinical Research Information System database at Dana-Farber Cancer Institute. For cohorts 1 and 3, the electronic medical record was reviewed to determine absolute lymphocyte counts (ALCs) and absolute neutrophil counts (ANCs) for day 1 of each of the 8 cycles of treatment. For cohort 2, data was prospectively collected and entered into an electronic database. The lowest ALC obtained by each patient on day 1 of any cycle was termed the nadir.

RESULTS

Patients experienced grade 3 (ALC < 500 cells/mm3) or grade 4 (ALC < 200 cells/mm3) lymphopenia in all 3 cohorts: 63% with dose-dense AC -->T, 23.4% in dosedense AC --> albumin-bound paclitaxel, and 69% with dose-dense AC --> T every 3 weeks. Patients experienced their lowest median ALC count at cycle 5 of treatment in all 3 cohorts, with a median nadir of 400 cells/mm3 in cohort 1, 690 cells/mm3 in cohort 2, and 400 cells/mm3 in cohort 3.

CONCLUSION

The majority of patients receiving AC --> T every 2 or 3 weeks experience grade 3/4 lymphopenia. Median lymphocyte counts appear to be lowest around cycle 5, the point at which we observed 2 cases of PCP. Lymphocyte counts appear to be reaching a low enough level to place patients at risk for opportunistic infection during treatment with dosedense AC --> T and with AC --> T given every 3 weeks.

Idiopathic CD4+ lymphocytopenia: natural history and prognostic factors

Idiopathic CD4(+) lymphocytopenia (ICL) is a rare non-HIV-related syndrome with unclear natural history and prognosis. This prospective natural history cohort study describes the clinical course, CD4 T lymphocyte kinetics, outcome, and prognostic factors of ICL. Thirty-nine patients (17 men, 22 women) 25 to 85 years old with ICL were evaluated between 1992 and 2006, and 36 were followed for a median of 49.5 months. Cryptococcal and nontuberculous mycobacterial infections were the major presenting opportunistic infections. Seven patients presented with no infection. In 32, CD4 T-cell counts remained less than 300/mm(3) throughout the study period and in 7 normalized after an average of 31 months. Overall, 15 (41.6%) developed an opportunistic infection in follow-up, 5 (13.8%) of which were "AIDS-defining clinical conditions," and 4 (11.1%) developed autoimmune diseases. Seven patients died, 4 from ICL-related opportunistic infections, within 42 months after diagnosis. Immunologic analyses revealed increased activation and turnover in CD4 but not CD8 T lymphocytes. CD8 T lymphocytopenia (< 180/mm(3)) and the degree of CD4 T cell activation (measured by HLA-DR expression) at presentation were associated with adverse outcome (opportunistic infection-related death; P = .003 and .02, respectively).

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.

Idiopathic CD4 lymphocytopenia

PURPOSE OF REVIEW

A severe decrease of CD4 T cells predisposes humans to opportunistic infections. In adults, HIV is certainly the most common cause of CD4 lymphocytopenia, but other causes, such as infections, autoimmune diseases, immunosuppressive therapy, lymphoma and idiopathic forms need to be considered. This review summarizes the current knowledge of the poorly understood syndrome of idiopathic CD4 lymphocytopenia.

RECENT FINDINGS

Little research has tried to systematically dissect this probably heterogeneic syndrome after its initial description in 1992. Numerous cases presenting with opportunistic infections have been reported. Disturbed differentiation of stem cell precursors may contribute to CD4 lymphocytopenia. Because infections and lymphoma may also cause CD4 lymphocytopenia, the distinction between cause and effect may evolve only during follow-up.

SUMMARY

The manifestation of opportunistic infections calls for the evaluation of the immune system for CD4 lymphocytopenia. The differential diagnosis of this condition in adults comprises primarily HIV infection and less often other diseases or drugs. Idiopathic CD4 lymphocytopenia is very rare. The clinical significance of low CD4 cell counts in HIV negative patients still awaits its systematic analysis. Prophylaxis of opportunistic infections is oriented at the recommendations of HIV-infected individuals and causal treatment remains experimental.

Recognizing primary immune deficiency in clinical practice

Primary immunodeficiency results in recurrent infections, organ dysfunction, and autoimmunity. We studied 237 patients referred for suspicion of immunodeficiency, using a scoring system based on clinical information. The 113 patients with immunodeficiency had higher scores and more episodes of chronic illnesses and were more likely to have neutropenia, lymphopenia, or splenomegaly.

Diagnostic des déficits immunitaires primitifs à l’âge adulte

The molecular bases of approximately one hundred primary immune deficiencies (PID) have been identified over the last 15 years. In adults, the diagnosis of PID cannot be evoked before ruling out acquired immunodeficiencies, which are far more frequent. The search for specific PIDs may be oriented by the type of agent responsible for severe and/or recurrent infection. More rarely, other clinical manifestations such as granulomatosis, autoimmune manifestations, hemophagocytic syndrome, lymphoproliferation, or solid tumors may also lead to the identification of PID.

Lymphopenia at presentation is associated with increased risk of infections in patients with systemic lupus erythematosus

BACKGROUND

Patients with systemic lupus erythematosus (SLE) frequently suffer from infections, but the predisposing risk factors, as well as the exact frequency and nature of such infections, are not fully understood.

AIM

To describe the frequency, types and risk factors for infections in a group of Chinese patients in the early stage of SLE in Hong Kong.

DESIGN

Retrospective record study.

METHODS

We reviewed the case records of 91 Chinese SLE patients, presenting <12 months after SLE diagnosis. Details of major infections (requiring intravenous antimicrobial therapy, or any confirmed mycobacterial infection) and minor infections were reviewed. Clinical and laboratory features, the systemic lupus erythematosus disease activity index (SLEDAI) at presentation and drug treatment were recorded and analysed.

RESULTS

There were 48 major infections and 62 minor infections during 260 patient-years of follow-up. A lymphocyte count < or =1.0 x 10(9)/l at presentation was independently associated with an increased risk for major infection: hazard ratio 4.7 (95%CI 1.6-13.7), p = 0.005. SLEDAI, use of corticosteroids and immunosuppressive therapy were all not associated with increased risk of infection.

DISCUSSION

Lymphopenia was an important risk factor for major infections in this group of Chinese patients in the early stages of SLE. SLE patients with lymphopenia at presentation should be closely monitored for the development of infective complications.

Idiopathic CD4+ lymphocytopenia may be due to decreased bone marrow clonogenic capability

BACKGROUND

Idiopathic CD4+ lymphocytopenia is defined by a stable decrease of CD4+ T cells in the absence of any known cause of immune deficiency. The mechanisms responsible for the immunological impairment are still unknown, but a regenerative failure of hematopoietic stem/progenitor cells has been hypothesized.

METHODS

We evaluated in the bone marrow (BM) of 5 patients with idiopathic CD4+ lymphocytopenia the phenotype of BM progenitor cells, their differentiation capacity with colony-forming cells and long-term culture-initiating cell assays, in parallel with the spontaneous IL-7 production in the patient sera.

RESULTS

Compared with controls, a regenerative failure of hematopoietic stem cells has been observed, both in 'committed' and in 'uncommitted' progenitor cells, despite high IL-7 serum levels. The percentage of phenotypically primitive CD34+CD38-DR+ cells (this includes the lymphoid precursor cells) was decreased, suggesting an involvement of the more primitive BM compartment in the de novo T cell generation.

CONCLUSIONS

Despite the low number of patients, due to the low incidence of the disease, the decrease of primitive precursors sustains the possibility that diminished stem cell precursors might contribute to the development of CD4+ T cell depletion.

Idiopathic CD4+ lymphocytopenia and juvenile laryngeal papillomatosis

We report on an association of idiopathic CD4+ lymphocytopenia (ICL) and juvenile laryngeal papillomatosis (JLP) in a pediatric-aged patient. Because of a past medical history of recurrent lung infections and severe chickenpox in infancy, immunologic investigations were done at age 6 years. On several occasions, a CD4+lymphocyte count of <300 cells/mm3 was detected, supporting the diagnosis of ICL. During follow-up, both medical (interferon-alpha) and surgical treatments of JLP were only partially efficient. Our patient developed disseminated infection with Mycobacterium avium and died at 10 years of age. Human papillomavirus is an important pathogen in pediatric and adult patients with ICL. In pediatric patients with JLP who develop other unusually severe viral or opportunistic infections, immunological investigations should be considered.

Linfopenia em doentes submetidos a ventilação mecânica por exacerbação de insuficiência respiratória crónica: estudo prospectivo

OBJECTIVES

Evaluate and characterize lymphopenia in patients admitted to the Intensive Care Unit (ICU) for mechanical ventilation due to aggravated chronic respiratory failure and its probable relation to severity.

MATERIAL AND METHODS

Prospective study over a period of 6 months with another 6 months follow-up after ICU discharge. The study included 24 patients, 22 males, with mean APACHE II of 19,7, three of whom with capacity for outpatient follow-up. Lymphocyte subpopulations were determined on admission and every 7 days after mechanical ventilation. Patients with evidence of infection or previous immunossupression, with the exception of steroids, were excluded from the study.

RESULTS

Lymphopenia was found in 79,2% of patients with depletion of all lymphocyte series, although with greater expression for B lymphocytes CD19+. This depletion showed no relation with serum steroid levels, and although related to greater clinical severity, no correlation was found with mortality. Lymphocyte values recovered progressively during admission.

CONCLUSIONS

Lymphopenia is frequent among ventilated patients with chronic respiratory exacerbation. It's a non-selective depletion, more evident with CD19+ B lymphocytes. These patients present higher severity scores but no difference in mortality. Outpatient follow-up was difficult and inconclusive.

Proteomic analyser with applications to diagnostics and vaccines

This paper describes a method for proteomic analysis with applications to diagnostics and vaccines. A panel of N (⪢1) reagents called X(j), with j=1 to N, is used. The binding strength of each of the X(j) reagents to each other is measured, for example by an ELISA assay, giving an N×N matrix K. The matrix K is used to define another set of N reagents called Y(j), with j=1 to N, each of which is a linear combination of the X(j) reagents and each of which is tailored to be complementary to one of the X(j) reagents. Each of the N pairs of reagents X(j) and Y(j) defines an axis in an N-dimensional shape space. The definition of these axes facilitates proteomic analysis of diverse biological samples, for example, mixtures of proteins such as serum samples or T cell extracts. A method for defining and measuring similarity between pairs of biological samples and between sets of biological samples in the context of the set of N reagent pairs is described. This leads to methods for using the N reagent pairs in the diagnosis of diseases and in the formulation of preventive and therapeutic vaccines. The relationship of this work to previous research on shape space is discussed.

Histoplasmose do sistema nervoso central como única manifestação da doença em pacientes imunocompetentes: apresentação de dois casos

Apresentamos dois casos de histoplasmose em que o acometimento do sistema nervoso central foi a única manifestação clínica da doença. Revisão da literatura permitiu confirmar a raridade dessa forma de patologia, em particular em crianças, sendo o segundo caso aqui apresentado o de mais baixa idade na literatura nacional. São feitos comentários sobre a variedade das apresentações clínicas e os principais diagnósticos diferenciais da doença. São discutidos os resultados laboratoriais, tanto em relação às alterações liquóricas quanto aos resultados sorológicos. Finalmente, é analisada a terapêutica dessa forma de infecção fúngica tanto em relação aos medicamentos utilizáveis quanto à duração prolongada aconselhável para o tratamento específico.

Pleural effusion due to Histoplasma capsulatum and idiopathic CD4 lymphocytopenia

Acute histoplasmosis is usually a benign, self-limited infection in endemic areas. Since protection against Histoplasma capsulatum infection requires specific, cell-mediated immunity, histoplasmosis is well documented in patients with acquired T cell deficiencies e.g. due to HIV infection. We report here for the first time a case of pleural effusion due to H. capsulatum infection in a patient with idiopathic CD4 lymphocytopenia (ICL). A 25-year-old woman presented with chest pain, dyspnea on exertion and a moderate weight loss. Chest X-ray showed a large left pleural effusion, and thoracentesis yielded an exudate. Histologic examination of pleural biopsies identified H. capsulatum. Laboratory tests revealed lymphocytopenia with low CD4+ T cell counts (<100/microl) and a decreased CD4/CD8 ratio. Serology, including HIV, was repeatedly negative. The diagnosis of pleural effusion due to H. capsulatum infection in a patient with idiophatic ICL was established. There was no evidence of any other opportunistic infection. Treatment with itraconazole was initiated and pleural effusion resolved within 2 weeks of treatment. Moreover, the patient was found to have idiopathic thrombocytopenic purpura, as confirmed by the detection of autoantibodies against thrombocytes. In a 1-year follow-up, the patient remained asymptomatic without relapse or any new infection. Treatment with itraconazole was given for 12 months. Because of persistent CD4+ T cell counts below 100/microl, prophylactic antibiotic treatment is continued.

Idiopathic CD4+T-cell lymphocytopenia associated with vitiligo

The syndrome of idiopathic CD4+ T lymphocytopenia (ICTL) is defined as the persistent depletion of peripheral blood CD4+ T lymphocytes below 300 cells/mm(3) or less than 20% of the total lymphocytes in the absence of either HIV infection or other known causes of immunodeficiency. To date no known viral origin has been identified. ICTL has a variable clinical course ranging from patients with minimal symptoms to those who have died from opportunistic infections. We report a case of a 32-year-old white man with a long history of vitiligo that is associated with ICTL. He also had incidental psoriasis. The correlation between ICTL and autoimmune vitiligo suggests an aberration in the immune surveillance that leads to an abnormal response of CD4+ T lymphocytes in the host.

Primary leptomeningeal lymphoma in a patient with concomitant CD4+ lymphocytopenia

BACKGROUND

Idiopathic CD4+ lymphocytopenia (ICL) is a rare disorder in which patients have mild and/or severe opportunistic infections or maybe without symptoms. The etiology is currently unknown. Diagnosis is made by excluding retroviral infections (human immunodeficiency virus-1 or -2, human T cell lymphotropic virus-1 or -2) or other known causes of immunosuppression.

OBJECTIVE

To provide a case report of a patient with possible ICL who presented with a rare form of primary non-Hodgkin lymphoma (NHL) of the central nervous system (CNS). Review of the literature has identified only five other patients with NHL and ICL; however, none of these had a CNS lymphoma.

RESULTS

We describe a patient with possible ICL, and address links between lymphopenia and lymphoproliferative disorders.

CONCLUSIONS

Although not uncommon for patients infected with human immunodeficiency virus to develop CNS NHL, this is the first case of a possible ICL patient with such a lymphoma. This case revisits an important relationship between lymphopenia and lymphoproliferative disorders.

Profound T-lymphocytopenia and cryptococcemia in a human immunodeficiency virus-seronegative patient with disseminated tuberculosis

A 47-year-old human immunodeficiency virus-seronegative West African man who presented in extremis with cachexia, lymphadenopathy, multiple organ dysfunction, and marked T-lymphocytopenia received the diagnosis of disseminated tuberculosis, cryptococcal pneumonia, and cryptococcemia. His subsequent course and our review of the literature suggest that the profound T-lymphocytopenia and ensuing cryptococcal disease were likely attributable to disseminated tuberculosis.