Evidence of B cell clonal expansion in HIV type 1-infected patients

Myeloma Cast Nephropathy an Unusual Association with HIV Infection Presenting with Renal Dysfunction

Human immunodeficiency virus (HIV)-associated renal disease is a pan-nephropathy, causing glomerular, tubular, and interstitial changes. The common lesion is the collapsing variant of focal segmental glomerulosclerosis. Multiple myeloma presenting as light chain cast nephropathy in an HIV-positive patient is very rare. A 45-year-old female retropositive patient presented with one episode of hematuria. Kidney biopsy was performed with a clinical diagnosis of acute interstitial nephritis (AIN). Biopsy showed unremarkable glomeruli. Tubules were dilated and showed a few periodic acid-Schiff (PAS) positive and many PAS-negative fractured casts surrounded by histiocytic reaction. Immunofluorescence and immunohistochemistry (IHC) showed lambda restriction by the casts. Bone marrow aspirate showed an increase in plasma cells, and the biopsy showed nodular aggregates of atypical plasma cells, which showed lambda restriction by IHC. PAS-negative fractured tubular casts are known to be associated with HIV-related nephropathy and need detailed hematological workup to rule out an associated plasma cell dyscrasia.

Plasma cell disorders in HIV-infected patients: epidemiology and molecular mechanisms

Highly active antiretroviral therapy (HAART) has significantly improved the outcome and survival of human immunodeficiency virus (HIV)-infected patients. Subsequently, long-term morbidities including cancer have become of major public health and clinical interest for this patient population. Plasma cell disorders occur at higher incidence in HIV-infected patients; however, the molecular mechanisms driving the plasma cell disease process and the optimal management for these patients remain to be defined. This article provides an up-to-date review of the characteristics and management of HIV-infected patients with plasma cell disorders. We first present 3 cases of plasma cell disorders in HIV-infected patients, ranging from polyclonal hypergammaglobulinemia to symptomatic multiple myeloma. We then discuss the epidemiology, clinical presentation, and management of each of these plasma cell disorders, with an emphasis on the molecular events underlying the progression of plasma cell diseases from monoclonal gammopathy to symptomatic multiple myeloma. We propose a three-step hypothesis for the development of multiple myeloma. Finally, we discuss the use of high dose chemotherapy and autologous hematopoietic stem cell transplantation in the treatment of HIV-infected patients with multiple myeloma. Our review includes the care of HIV-infected patients with plasma cell disorders in the current era of HAART and novel agents available for the treatment of multiple myeloma.

Characterization of human IgG repertoires in an acute HIV-1 infection

All known broadly neutralizing antibodies (bnAbs) are highly somatically mutated and therefore significantly differ from their germline predecessors. Thus although the mature bnAbs bind to conserved epitopes of the HIV-1 envelope glycoprotein (Env) with high affinity their germline predecessors do not or weakly bind Envs failing to initiate an effective immune response. The identification of less somatically mutated bnAbs and/or antibody maturation intermediates that are clonally related to bnAbs may be useful to circumvent the major problem of initiating immune responses leading to elicitation of bnAbs. Here, we describe the identification of IgG antibodies from an acutely HIV-1-infected patient using a combination of phage display and high-throughput sequencing. We found two antibodies with only a single point mutation in the V region of their heavy chain variable domains compared to their putative germline predecessors which bound with high affinity to several Envs. They targeted the Env gp41 and did not neutralize HIV-1. Using high-throughput sequencing, we identified several highly abundant CDR3s, germline-like as well as somatically mutated V genes in the VH/VL repertoires of the patient which may provide antibody intermediates corresponding to known bnAbs as templates for design of novel HIV-1 vaccine immunogens.

Cryptococcus neoformans-reactive and total immunoglobulin profiles of human immunodeficiency virus-infected and uninfected Ugandans

We determined total and Cryptococcus neoformans glucuronoxylomannan (GXM)-reactive antibody repertoires of human immunodeficiency virus (HIV)-infected and HIV-uninfected Ugandans in a retrospective, case-control study of participants in a randomized controlled trial of pneumococcal vaccination. The study included 192 adults: 48 who subsequently developed cryptococcal meningitis (CM); (HIV+ CM+); 2 individuals who matched them in CD4+ T-cell level, stage of HIV disease, and age but did not develop CM (HIV+ CM-); and 48 HIV-uninfected individuals. Total serum immunoglobulin concentrations and titers of immunoglobulin M (IgM), IgG, and IgA to GXM, pneumococcal polysaccharides, and antibodies expressing certain V(H)3 idiotypes were determined with banked sera obtained before the development of cryptococcosis for HIV+ CM+ subjects. The results showed that HIV-infected subjects had significantly lower levels of IgM to GXM but higher levels of total immunoglobulin and IgG and IgA to GXM than those of HIV-uninfected subjects. HIV-infected subjects with a history of pneumonia had higher levels, and those with a history of herpes zoster had lower levels of GXM-binding antibodies than subjects with no history of either disease. Minimal to no cross-reactivity was demonstrated between antibodies to GXM and polysaccharides in a pneumococcal vaccine. No significant differences between the antibody repertoires of HIV+ CM+ and HIV+ CM- subjects were identified, but among subjects without a history of pneumonia, there was a trend towards lower V(H)3-positive antibody levels among HIV+ CM+ than among HIV+ CM- subjects. Our findings demonstrate an association between previous infectious diseases and differences in the total and GXM-reactive antibody repertoires of HIV-infected subjects and suggest the question of whether certain microbes modulate subsequent antibody responses to GXM deserves further study.

Increased levels of galactose-deficient IgG in sera of HIV-1-infected individuals

BACKGROUND

The IgG from sera of patients with chronic inflammatory diseases of autoimmune character or some chronic microbial infections is frequently deficient in galactose on N-linked glycans. However, this phenomenon has not been investigated at length in human viral infections.

OBJECTIVES

To evaluate the glycosylation of serum IgG in HIV-1-positive patients.

METHODS

Psathyrella velutina lectin was used in enzyme-linked immunosorbent and Western blot assays to determine glycosylation. In addition, gas-liquid chromatography and mass spectrometry were utilized to confirm the galactose deficiency observed in the lectin-binding assays.

RESULTS

HIV-1-infected individuals had significantly higher levels of galactose-deficient IgG than healthy controls. In fact, the galactose deficiency of the N-linked glycans observed in other diseases was even more profound in HIV-1 infection. This deficiency was primarily restricted to IgG when total serum glycoproteins were evaluated and IgG1 was the subclass most affected in all patients. Also, a significant increase in lectin binding was observed on IgG2 and IgG4 from HIV-1-positive females compared with HIV-1-negative females.

CONCLUSIONS

Identification of deficient galactosylation of serum IgG from HIV-1-infected patients extended the spectrum of diseases in which this phenomenon has been observed. In addition, the results suggest yet another aspect of immune dysfunction as a result of HIV-1 infection.

Downregulation of CXCR5 in CD27- B cells of HIV-1 infected patients

The CD27(-) (naive) B cells of HIV-1 infected patients have been shown to be increased in frequency and to be activated, as indicated by high CD38 expression on the cell surface. CXCR5, a B cell chemokine receptor, is expressed on circulating CD27(-) (naive) B cells and plays a pivotal role in peripheral B cell development. To investigate the effect of HIV-1 infection on the expression of this chemokine receptor on naive B cells, the expression level of CXCR5 on CD27(-) B cells was examined in 19 drug-naive HIV-1 infected patients, 27 HAART-treated patients, and 20 controls. CXCR5 expression on CD27(-) B cells was significantly lower in drug-naive patients than in HAART-treated patients and controls (P < 0.01). CD27(-) B cells with high CD38 expression exhibited low CXCR5 expression. The CXCR5 expression level on CD27(-) B cells recovered to within the normal range after effective antiretroviral therapy. These findings suggested that HIV-1 infection induces a remarkable phenotypic alteration of naive B cells and that the activated naive B cells found in HIV-1 infection downregulate CXCR5 on their surface. Impaired homing of naive B cells may contribute to HIV-1 induced immunological deficiencies.

Host-dependent serum specificity to the V3 domain of HIV-1

The previous studies of anti-HIV-1 humoral immune response have found the stable individual structural bias in the antibody production that reflects the changes in the immune functional network caused by HIV-1. The correlation between antigen structure, in particular the V3 domain of HIV-1, and the serum specificity to the structure remains unclear. To clarify the role of host individual factors in the serum specificity, we used the slightly modified HIV-1 serotyping methodological approach for the sera of the patients infected with HIV-1 with a different level of genetic similarity. Substantial discrepancy between serum specificities and antigen structure was found. Patients infected with HIV-1 carrying similar and identical V3 sequences had significantly different serum specificities. The opposite situation was often observed as well. The results of the study suggest that the influence of the V3 loop structure in the development of humoral immune response to the V3 loop is substantially modified in a patient-specific manner.

Longitudinal analysis of B cell repertoire and antibody gene rearrangements during early HIV infection

In chronically HIV infected individuals, a number of functional B cell abnormalities have been described. However, the immediate changes that occur in the B cell compartment following viral exposure and how they affect the long-term course of infection are not well understood. We report the longitudinal analysis of B cell repertoires during early infection in untreated and treated individuals receiving highly active antiretroviral therapy (HAART). Analysis was based on IgG heavy chain gene utilization and CDR3 length measurement and relationship with CD4/CD8 counts, viral load, and total serum IgG, and anti-HIV antibodies levels. Repertoires were assessed at baseline and at weeks 2, 4, 12, 24, and 72 after initiation of therapy. The findings indicate a stable peripheral B cell repertoire during the first 72 weeks following infection, particularly in the HAART treated patients. A modest association between B cell repertoire integrity and viremia levels as well as treatment was detected.

Paucity of antigen-specific IgA responses in sera and external secretions of HIV-type 1-infected individuals

This study was undertaken to resolve existing controversies with respect to the detection of IgA HIV-1-specific mucosal antibodies in infected individuals. External secretions, including tears, nasal, rectal, and vaginal washes, saliva, semen, urine, and sera were obtained from 50 HIV-1-infected individuals and 20 controls using collection procedures that minimize the irritation of mucosal surfaces. Levels of total and antigen (gp120 and gp160)-specific antibodies of the IgG and IgA isotypes were measured by assays that proved reliable in a large multicenter study: quantitative ELISA and chemiluminescence-enhanced Western blot analyses. Although the levels of total IgG and IgA were increased or remained unchanged in body fluids of HIV-1-infected individuals as compared to the controls, HIV-1-specific IgA antibodies were either absent or present at low levels even in secretions with characteristically high relative contents of total IgA vs. IgG (saliva, tears, and rectal and nasal washes). In these secretions, HIV-1-specific IgG antibodies dominated. In assessing levels and frequency of detection of IgG antibodies, both female and male genital tract secretions, urine, and nasal wash were preferable to parotid saliva and especially to rectal wash. External secretions contained IgG antibodies to gp160> gp120> gp41 and p24; when present, IgA antibodies were predominantly directed at gp160. Analyses of peripheral blood antibody-secreting cells (ASC) isolated from the same individuals paralleled these serological findings: gp160-specific IgG-secreting ASC were dominant. Therefore, in striking contrast to other mucosally encountered microbial infections, HIV-1 does not induce vigorous specific IgA responses in any body fluid examined or in ASC in peripheral blood.

Increased frequency of CD27- (naive) B cells and their phenotypic alteration in HIV type 1-infected patients

To investigate HIV-1-related B cell disorders, the quantity of peripheral CD27 negative (CD27-) B cells, their CD38, CD95, and bcl-2 intensities, and their apoptosis susceptibility were examined by flow cytometry analysis in 16 drug-naive patients, 27 HAART-treated patients, and 20 uninfected controls. CD27- B cells have been recognized as naive B cells. The mean percentage of CD27- B cells was significantly higher in drugnaive patients (88.1%) and in HAART-treated patients (83.9%) than in controls (68.6%) (p < 0.01). The intensities of CD38 and CD95 on CD27- B cells were significantly higher in drug-naive patients than in controls (p < 0.01). The intensity of CD95 on CD27- B cells in HAART-treated patients was lower than that of drug-naive patients, but significantly higher than that of controls (p < 0.01). The intensity of bcl-2 on CD27- B cells in drug-naive patients was lower than that of controls. In drug-naive patients, CD27-B cells with high CD38 expression represented low bcl-2 expression. The CD27- B cells of drug-naive patients showed an increased susceptibility to apoptosis, characterized by diminished cell size and a high frequency of annexin-V binding, compared with controls and HAART-treated patients. These findings suggested that HIV-1 infection affects peripheral CD27- (naive) B cells as well as CD27+ (memory) B cells and that CD27- B cells might be activated and rendered highly susceptible to apoptosis by HIV-1 infection. Some phenotypic alterations in CD27- B cells may continue after the reduction of HIV-1 loads by effective antiviral therapy.

Selective CD27+ (memory) B cell reduction and characteristic B cell alteration in drug-naive and HAART-treated HIV type 1-infected patients

To investigate HIV-1-related B cell disorders, the quantity of CD27 positive (CD27+) B cells and their CD38, CD95, and bcl-2 intensities were examined by flow cytometry analysis in 16 drug-naive patients, 27 highly active antiretroviral therapy (HAART)-treated patients, and 20 uninfected controls. CD27+ B cells have been recognized as memory B cells. The mean percentage of CD27+ B cells was significantly lower in drug-naive patients (11.9%) and in HAART-treated patients (16.1%) than in controls (31.4%) (p < 0.01). The intensities of CD38 and CD95 on CD27+ B cells were higher in drug-naive patients than in controls (p < 0.01 in CD95). The intensity of CD95 on CD27+ B cells in HAART-treated patients was lower than that of drug-naive patients, but significantly higher than that of controls (p < 0.01). The intensity of bcl-2 on CD27+ B cells was equivalent among the three groups. These findings suggest that disturbance of peripheral B cell composition, exemplified by CD27+ B cell reduction, exists in both drug-naive and HAART-treated HIV-1-infected patients. In addition, the augmented apoptotic state of CD27+ B cells found in HAART-treated patients with undetectable viral loads, indicated by CD95 elevation, suggests that some HIV-1-related B cell disorders last for years after effective antiviral therapy.

Changes in Immunoglobulin Isotypes and Immunoglobulin G (IgG) Subclasses During Highly Active Antiretroviral Therapy

SUMMARY

The effects of highly active antiretroviral therapy (HAART) on immunoglobulin isotypes and immunoglobulin G (IgG) subclasses were studied in 12 patients in early stages of HIV-1 infection. Blood samples were obtained at enrollment and 2, 4, 8, 12, 24, 48, and 120 weeks after initiation of HAART. Immunoglobulin concentrations were determined by nephelometry, and anti-p24-specific IgG and IgG1 levels were determined by an enzyme immunoassay. Overall time changes were analyzed in analysis of variance models. IgG and IgG1 levels showed a marked overall decline, whereas other immunoglobulin isotypes and IgG subclasses did not change significantly. Anti-p24-specific IgG1 levels decreased considerably and significantly more in virus isolation-negative patients than in virus isolation-positive patients, as defined according to the ability to isolate HIV-1 from their CD4+ T cells after initiation of therapy. Anti-p24 IgG levels showed a similar but overall weaker decline in the two groups. However, the anti-p24 IgG1 level followed the biphasic decline in plasma viremia more closely than the anti-p24 IgG level, with an initial sharp decline that leveled off with time. These findings suggest that the main reduction in immunoglobulin levels is caused by reduced HIV-1-specific antigen stimulation rather than a general reduction in immune activation. Using anti-p24 IgG1 as a parameter of response to the effect of HAART merits further investigation.