Peripheral blood marker of residual acute leukemia after hematopoietic cell transplantation using multi-plex digital droplet PCR

Background

Relapse remains the primary cause of death after hematopoietic cell transplantation (HCT) for acute leukemia. The ability to identify minimal/measurable residual disease (MRD) via the blood could identify patients earlier when immunologic interventions may be more successful. We evaluated a new test that could quantify blood tumor mRNA as leukemia MRD surveillance using droplet digital PCR (ddPCR).

Methods

The multiplex ddPCR assay was developed using tumor cell lines positive for the tumor associated antigens (TAA: WT1, PRAME, BIRC5), with homeostatic ABL1. On IRB-approved protocols, RNA was isolated from mononuclear cells from acute leukemia patients after HCT (n = 31 subjects; n = 91 specimens) and healthy donors (n = 20). ddPCR simultaneously quantitated mRNA expression of WT1, PRAME, BIRC5, and ABL1 and the TAA/ABL1 blood ratio was measured in patients with and without active leukemia after HCT.

Results

Tumor cell lines confirmed quantitation of TAAs. In patients with active acute leukemia after HCT (MRD+ or relapse; n=19), the blood levels of WT1/ABL1, PRAME/ABL1, and BIRC5/ABL1 exceeded healthy donors (p<0.0001, p=0.0286, and p=0.0064 respectively). Active disease status was associated with TAA positivity (1+ TAA vs 0 TAA) with an odds ratio=10.67, (p=0.0070, 95% confidence interval 1.91 - 59.62). The area under the curve is 0.7544. Changes in ddPCR correlated with disease response captured on standard of care tests, accurately denoting positive or negative disease burden in 15/16 (95%). Of patients with MRD+ or relapsed leukemia after HCT, 84% were positive for at least one TAA/ABL1 in the peripheral blood. In summary, we have developed a new method for blood MRD monitoring of leukemia after HCT and present preliminary data that the TAA/ABL1 ratio may may serve as a novel surrogate biomarker for relapse of acute leukemia after HCT.

Influence of antipsychotics on metabolic syndrome risk in patients with schizophrenia

OBJECTIVE

Many studies so far have shown that antipsychotic therapy may have an effect on the development of metabolic syndrome in patients diagnosed with schizophrenia. Our goal was to determine whether our respondents are at risk for developing metabolic syndrome and who is more predisposed to it.

METHODS

In a stable phase, 60 patients diagnosed with schizophrenia were equally divided into three groups according to the drug (risperidone, clozapine, and aripiprazole monotherapy). Control group had 20 healthy examinees. Patients were evaluated first using The Positive and Negative Syndrome Scale (PANSS). Prolactin, lipid status, glycemia, insulin, cytokine values (IL-33, TGF-β, and TNF-α) and C-reactive protein (CRP) were measured. Also, Body mass index (BMI), Homeostatic Model Assesment for Insulin Resistance (HOMA index), waist and hip circumference (WHR) and blood pressure (TA) measurement were performed in the study.

RESULTS

Patients treated with risperidone compared to healthy control subjects and aripiprazol group of patients had statistically significant difference in prolactin levels. In clozapine group compared to healthy control group values of HDL cholesterol and glucose level were statistically significant different. In aripiprazole group compared to healthy control group value of BMI was statistically significant different. Statistically significant correlations were found in TNF-α with glucose and HOMA index in risperidone treated patients and with BMI in clozapine group of patients; IL-33 with glucose in risperidone and with BMI in clozapine group of patients and TGF-β with glucose in risperidone group, with insulin and HOMA index in clozapine group and statistically significant negative correlation with LDL cholesterol in aripiprazole group of patients.

CONCLUSION

Patients on risperidone and clozapine therapy may be at greater risk of developing metabolic syndrome than patients treated with aripiprazole. Statistically significant difference in concentration of TNF-α and TGF-β was in the group of patients treated with risperidone compared to healthy control group.

Comparison of Demographic, Epidemiological, Immunological, and Clinical Characteristics of Patients with HIV Mono-infection Versus Patients Co-infected with HCV or/and HBV: A Serbian Cohort Study

OBJECTIVE

The study aimed to correlate the status of hepatitis C (HCV) and hepatitis B virus (HBV) co-infection in patients with human immunodeficiency virus (HIV) infection with clinical and demographic data prior to starting highly active antiretroviral therapy (HAART) and assess the impact of HCV and HBV co-infection on the natural history of HIV infection.

PATIENTS AND METHODS

The study involved a total of 836 treatment-naive patients with available serological status for HBV and HCV at the point of therapy initiation. Patients were stratified into four groups: HIV mono-infection, HIV/HCV, HIV/HBV, and HIV/HCV/HBV co-infection. Demographic, epidemiological, immunological and clinical characteristics were analyzed in order to assess the possible impact of HCV and HBV co-infection on HIV - related immunodeficiency and progression to AIDS.

RESULTS

The prevalence of HCV and HBV co-infection in our cohort was 25.7% and 6.3%, respectively. Triple HIV/HCV/HBV infection was recorded in 1.7% of the patients. In comparison with those co-infected with HCV, patients with HIV mono-infection had lower levels of serum liver enzymes activity and higher CD4 cell counts, and were less likely to have CD4 cell counts below100 cells/µL and clinical AIDS, with OR 0.556 and 0.561, respectively. No difference in the development of advanced immunodeficiency and/or AIDS was recorded between patients with HIV monoinfection and those co-infected with HBV, or both HCV/HBV.

CONCLUSION

HIV/HCV co-infection was found to be more prevalent than HIV/HBV co-infection in a Serbian cohort. Co-infection with HCV was related to more profound immunodeficiency prior to therapy initiation, reflecting a possible unfavorable impact of HCV on the natural history of HIV infection.

Extensive depolarization and lack of recovery of leech Retzius neurons caused by 2,4 diaminobutyric acid

In this paper we present, for the first time, a detailed account of electrophysiological effects of 2,4-diaminobutyric acid (2,4-DABA). 2,4-DABA is a neurotoxic non-protein amino acid produced by Cyanobacteria with a possible link to neurodegenerative disorders in animals and humans. Intracellular recordings were performed on Retzius nerve cells of the leech Haemopis sanguisuga using glass microelectrodes filled with 3 mol/L KCl. Our results show that 2,4-DABA is an excitatory amino acid, causing membrane depolarization in a concentration-dependent manner. The most prominent depolarizations of 39.63±2.22 mV and 47.05±4.33 mV, induced by 5×10^-3 and 10^-2 mol/L 2,4-DABA respectively, are several times larger than maximal depolarizations induced by either Glutamate, Aspartate, β-N-methylamino-alanine (BMAA) or β-N-oxalylamino-alanine (BOAA) on our model. These 2,4-DABA induced depolarizations evolve through two distinct stages, which is a novel phenomenon in electrical cell activity upon application of an excitatory amino acid, at least on our model. Involvement of two separate mechanisms, suggested by the two stage phenomenon, is discussed in the paper. We also provide evidence that 2,4-DABA induces irreversible functional disturbances in neurons in a concentration-dependent manner, since only half of the cells recovered normal electrical activity after application of 5×10^-3 mol/L 2,4-DABA, and none recovered after application of 10^-2 mol/L 2,4-DABA. Effects of both L-2,4-DABA and DL-2,4-DABA were tested and are not significantly different.

Comparative Survival Analysis of Urea Kinetic Based Indices

Background

Although urea kinetic modeling indices for measuring dialysis dose are recommended by world expert groups, it is not quite clear whether some of these are superior in predicting the outcome over others. This prospective, single-center study was carried out with the aim to compare predictive value of different indices and methods of measuring dialysis dose.

Methods

The analysis included 93 anuric patients having been on hemodialysis for at least 2 years who were followed-up for 75-months. The dialysis dose was measured by Kt/V (formal UKM, 3 and 2 urea samples), Kt/V (Daugirdas), Kt/V (Lowrie), eKt/V (Daugirdas), URR and TAC urea.

Results

Correlations between dialysis indices and survival time were significant for all indices (p<0.01) except for TAC. All indices, except for TAC urea, were significant predictors of mortality (multivariate Cox regression analysis; p<0.01) and differences of significant levels among these colinear parameters were small.

Conclusion

All examined indices except for TAC urea were highly predictive of patient mortality. Daugirdas and Lowrie simplified Kt/V indices are as predictive of all-cause mortality as more complex formal UKM methods in long-term patients on a 3×4h/week schedule.

Hemodialysis Modality, Percentage of Body Fat, and Patient Survival

Background

A number of studies have reported lower mortality of overweight hemodialysis patients. This post hoc analysis of an observational prospective single-center study was aimed at elucidating whether both being overweight and surviving longer could result from changes in the hemodialysis modality.

Methods

The study included a cohort of 242 patients who were gradually switched from cuprophane membrane and acetate dialysis to polysulfone (including high-flux) membranes and bicarbonate dialysis. The analysis involved 12 months of baseline data obtained during the first calendar year after the patients entered the study (1994–2001) and repeated measurements for up to 132 months of follow-up (until 2004). Anthropometric measurements were made during the winter season and the percentage of body fat (%fat) was calculated from triceps, biceps, subscapular, and suprailiac skinfolds (K/DOQI guidelines). Kt/V, normalized protein catabolic rate, and cardiovascular comorbidity were also determined and laboratory analyses undertaken.

Results

Significant correlations were found between %fat and bicarbonate dialysate as well as polysulfone membrane and high-flux membrane. The linear mixed model showed dependence of %fat on polysulfone and high-flux membrane (p<0.01) Multivariate Cox regression (time-dependent covariates) found %fat to be an independent factor for longer survival, in addition to polysulfone and high-flux membranes.

Conclusion

Changes in hemodialysis modality were followed by both higher body fat percentage and patient survival. The reverse epidemiology of overweight patients might be at least partially the result of the influence of nonnutritional factors, such as a change in hemodialysis modality (introducing biocompatible high-flux and low-flux membranes and bicarbonate dialysis).

Failure to detect viral RNA in bat samples collected in the Balkan region

Bats represent a known reservoir of emerging viruses, yet no molecular data are found about the occurrence of zoonotic viruses in bats in the Balkans. The aim of this study was to determine the presence of paramyxo- and hanta-viruses in bats, examined by PCR in 95 deceased bats, that were collected in Serbia and Montenegro, during the period 2002 to 2009. All samples tested positive for beta-actin mRNA, confirming successful RNA isolation and amplification. However, no sample tested positive for virus specific RNA. Our findings might reflect tissue degradation in carcass samples and do not exclude bats as potential viral reservoir in the surveyed geographic area.

Prenatal Diagnosis of a Fetal Epidural Hematoma

A fetal epidural hematoma is a rare finding during the prenatal period, with different etiologies such as maternal trauma, infections, or maternal use of specific medications such as warfarin. Both ultrasonography and magnetic resonance imaging (MRI) have been used successfully to evaluate the fetal central nervous system. Although these methods are also useful in detecting and evaluating a fetal epidural hematoma, brain function of the neonate cannot be exactly predicted on the basis of the prenatal findings. According to the literature data to date, this is the first reported case of prenatally detected fetal epidural hematoma of unknown etiology with a good outcome.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Primary resistance to integrase strand-transfer inhibitors in Europe

OBJECTIVES

The objective of this study was to define the natural genotypic variation of the HIV-1 integrase gene across Europe for epidemiological surveillance of integrase strand-transfer inhibitor (InSTI) resistance.

METHODS

This was a multicentre, cross-sectional study within the European SPREAD HIV resistance surveillance programme. A representative set of 300 samples was selected from 1950 naive HIV-positive subjects newly diagnosed in 2006-07. The prevalence of InSTI resistance was evaluated using quality-controlled baseline population sequencing of integrase. Signature raltegravir, elvitegravir and dolutegravir resistance mutations were defined according to the IAS-USA 2014 list. In addition, all integrase substitutions relative to HXB2 were identified, including those with a Stanford HIVdb score ≥ 10 to at least one InSTI. To rule out circulation of minority InSTI-resistant HIV, 65 samples were selected for 454 integrase sequencing.

RESULTS

For the population sequencing analysis, 278 samples were retrieved and successfully analysed. No signature resistance mutations to any of the InSTIs were detected. Eleven (4%) subjects had mutations at resistance-associated positions with an HIVdb score ≥ 10. Of the 56 samples successfully analysed with 454 sequencing, no InSTI signature mutations were detected, whereas integrase substitutions with an HIVdb score ≥ 10 were found in 8 (14.3%) individuals.

CONCLUSIONS

No signature InSTI-resistant variants were circulating in Europe before the introduction of InSTIs. However, polymorphisms contributing to InSTI resistance were not rare. As InSTI use becomes more widespread, continuous surveillance of primary InSTI resistance is warranted. These data will be key to modelling the kinetics of InSTI resistance transmission in Europe in the coming years.

Typing of macrolide resistant group A streptococci by random amplified polymorphic DNA analysis

OBJECTIVE

Several studies of group A streptococci (GAS) have revealed that a small number of dominant resistant clones might be responsible for the spread of Streptococcus (S.) pyogenes resistance to macrolides. We aimed to determine the genetic diversity of macrolide resistant group A streptococci (MRGAS), isolated from patients with pharyngitis in Serbia.

MATERIALS AND METHODS

The clonal relationships among 76 MRGAS isolates collected during 2008 were studied using two molecular typing methods: emm typing and random amplified polymorphic DNA (RAPD) analysis. Isolates that share the same emm type and RAPD pattern were considered to belong to the same clone.

RESULTS

Out of 7 distinct emm types identified, the 3 most frequently occurring overall were emm12, emm75 and emm77 (> 90% of isolates). Although as many as 26 different RAPD patterns were found among the isolates studied, two clones with emm12 and emm77 accounted 32 out of 76 (42%) isolates.

CONCLUSIONS

The results indicate a polyclonal spread of erythromycin-resistant Streptococcus pyogenes in our country. Furthermore, predominance of two clones, particularly among emm12 and emm77 strains indicates that erythromycin-resistant GAS of the same clonal origin are widely distributed in Serbia.

Inhibitory role of monovalent ions on rat brain cortex adenylyl cyclase activity

Adenylyl cyclases, comprise of a large family of enzymes that catalyze synthesis of the cyclic AMP from ATP. The aim of our study was to determine the effect of monovalent ions on both basal, stimulated adenylate cyclase EC 4.6.1.1 (AC) activity and C unit of AC and on GTPase active G-protein in the synaptic membranes of rat brain cortex. The effect of ion concentration from 30 to 200 mM (1 mM MgCl2) showed dose-dependent and significant inhibition of the basal AC activity, stimulated and unstimulated C unit activity. Stimulation of AC with 5 μM GTPγS in the presence of 50-200 mM of tested salts showed inhibitory effect on the AC activity. From our results it could be postulated that the investigated monovalent ions exert inhibitory effect on the AC complex activity by affecting the intermolecular interaction of the activated α subunit of G/F protein and the C unit of AC complex an inhibitory influence of tested monovalent ions on these molecular interaction.

HIV-1 drug-resistance patterns among patients on failing treatment in a large number of European countries

BACKGROUND

Information about patterns of HIV-1 drug resistance among treatment-exposed patients is crucial for the development of novel effective drugs. Currently no system exists that monitors patterns of resistance in patients failing therapy.

METHODS

The study included 1,988 HIV-1 sequences from patients experiencing therapy failure collected between 2000 and 2004 in 15 European countries. Genotypic resistance was interpreted using the ANRS algorithm. Phenotypic resistance was predicted using the Virco geno- to phenotype system.

RESULTS

80.7% of the sequences included at least one drug-resistance mutation. Mutations were found for NRTIs (73.5%), NNRTIs (48.5%), and protease inhibitors (35.8%). Ninety percent of sequences with genotypic resistance harbored M184V, M41L, K103N, D67N, and/or T215Y. Among NRTIs, resistance was most frequently predicted for lamivudine. About half of all sequences had reduced susceptibility for NNRTIs. Resistance to most boosted protease inhibitors was found in < 25%. No sequence had resistance to all currently available drugs.

CONCLUSION

Levels of resistance among patients with therapy failure were high. The patterns of resistance reflect resistance to drugs available for a longer time. Fully suppressive regimens can be designed even for the most mutated HIV because boosted protease inhibitors have remained active against most circulating viruses and new drug classes have become available.

Comparison of the influence of thyroglobulin antibodies on serum thyroglobulin values from two different immunoassays in post surgical differentiated thyroid carcinoma patients

Measurement of serum thyroglobulin (Tg) is a highly specific test in the management of patients with differentiated thyroid cancer (DTC) after surgical treatment. The aim of our study was to evaluate and compare Tg levels in these patients found by radioimmunoassay (RIA) and immunoradiometric assay (IRMA) and to assess the influence of Tg antibodies (TgAbs) on the values obtained for Tg concentration. Both Tg and TgAb were determined postoperatively in the serum of 71 DTC patients using RIA Tg-PEG (INEP) and Tg IRMA (CIS) for Tg, together with TgAb (CIS) for circulating endogenous anti-TgAbs. The obtained concentrations were evaluated statistically. We found a significant difference of Tg concentrations between paired samples from the IRMA and RIA, although the intermethod comparison yielded satisfactory concordance of the two assays (Spearman correlation coefficient -0.792). Positive TgAb was found in 28.2% of the serum samples analyzed. Spearman rank correlation analysis revealed a significant negative relationship between serum TgAb and Tg level measured by IRMA (P=0.02), but not by RIA (P=0.417). On the other hand, our clinical data revealed that 1/18 and 3/18 patients with proven lymph node metastasis had Tg values below the detection limit by RIA and IRMA assay, respectively. Their sera were TgAb positive. We concluded that RIA was less prone to influence of TgAb than IRMA. As the presence of TgAbs may interfere in Tg measurement irrespective of the method selected for determination, this should be considered during the clinical management of these patients.

The antenatal development of fetal behavioral patterns assessed by four-dimensional sonography

The investigation of fetal intrauterine activities has been enabled by the development of two-dimensional ultrasound. It has been shown that the earliest signs of fetal motor activity can be in the late embryonic period, and that the characteristics of fetal motor patterns change constantly throughout gestation. During the first trimester of pregnancy, the repertoire and frequency fetal movement patterns constantly expand, whereas the second and third trimesters are characterized by the progressive organization of fetal activities into complex and clearly distinct behavioral patterns. The comparison of real time ultrasonic studies of fetal behavior with the morphological studies of fetal brains has revealed that the appearance of new behavioral patterns or the transition of existing patterns directly reflect the complex neurodevelopment processes. It has been suggested that the assessment of fetal behavioral patterns could give us insight into the integrity of fetal central nervous system and enable the early detection of cerebral dysfunctions. The development of a new ultrasonic technique, four dimensional sonography, could represent a significant improvement in the assessment of fetal behavior. According to the preliminary results, this new technique could open a new perspective for the investigations of fetal behavioral patterns and contribute significantly to our better understanding of complex neurodevelopmental events. The most important neurodevelopmental events, the basic technology of 4D ultrasound and its application in the assessment of functional development of fetal central nervous system will be the subject of this review.

Three-dimensional sonography in prenatal diagnosis: a luxury or a necessity?

Three-dimensional sonography revolutionized ultrasound imaging with its capacity to depict an unlimited number of planes in which the object of interest can be displayed. The addition of numerous modalities of image rendering promotes three-dimensional sonography to the top of the spectrum of diagnostic imaging in obstetrics and gynecology. The aim of this article is to present our experience in 3-D sonography during the second and third trimester of pregnancy and to give a comparative review of literature. 247 patients in gestational age ranging from 12 to 40 weeks of gestation were examined over a three year period. The majority of patients entered the study because fetal anomaly was suspected at two-dimensional sonography. Some patients were sent on to three-dimensional sonography because it was not possible to depict clearly normal fetal anatomy by two dimensional sonography. Out of 170 fetal anomalies three-dimensional sonographic analysis failed in only three cases. In all three anomaly was accompanied with severe oligohydramnios. Main advantages of three-dimensional ultrasound in perinatal medicine and antenatal diagnosis include scanning in the coronal plane, improved assessment of complex anatomic structures, surface analysis of minor defects, volumetric measuring of organs, "plastic" transparent imaging of fetal skeleton, spatial presentation of blood flow arborization and, finally, storage of scanned volumes and images. It is our decided opinion that three-dimensional sonography has gained a valuable place in prenatal diagnosis, becoming a necessity for every modern perinatal unit.

HBsAg as the antigen component of circulating immune complexes in HIV-infected patients

Seeing the same transmission pattern of HIV and HBV coinfection by these two agents is not an uncommon feature. Immunity impairment due to HIV infection can be the cause of a higher rate of HBV replication with less intensive liver damage and less effective immune response to HBV, while the pathological course in both infections involves elevated levels of circulating immune complexes (CIC). These were the reasons for us to examine the frequency of HBsAg involvement as the antigen component of circulating immune complexes formed in sera of HIV-infected patients in different stages of HIV disease. We tested 67 sera of HIV-positive patients in different stages of HIV disease for the presence of HBsAg and HIV antigen p24 (with and without acid dissociation of immune complexes), for the presence of anti-Hbc antibodies and circulating immune complexes. HBsAg was positive in 13.8% sera prior to and 33.8% after acid pretreatment. Anti-HBc antibodies were present in 76.9% serum samples tested. Fifty percent of sera were positive for both HBsAg and p24 antigen after dissociation of immune complexes. The level of CIC was elevated in 65.9% of sera. Our results suggest that HBsAg is commonly associated in immune complexes formed in the sera of HIV-infected patients and that they may simultaneously contain HIV and HBsAg in patients coinfected with both agents. This may contribute to their mutual interaction and influence the diagnosis and follow-up of patients.

Antigen/antibody content of circulating immune complexes in HIV-infected patients

Dual infection with HIV and hepatitis B virus (HBV) is not an uncommon feature. Immunity impairment due to HIV infection can be the cause of a higher rate of HBV replication with less intensive liver damage and less effective immune response to HBV. Many HIV-infected patients have an elevated level of circulating immune complexes (CIC) in serum, throughout all stages of illness evolution. The aim of our study was to estimate p24 and HBsAg content of CIC in dually infected patients, and the prevalence of major classes of complexed antibodies (IgM and IgG). We examined 146 samples of sera from 105 HIV positive patients of the Institute for Infectious and Tropical Diseases during 1992 and 1993. On those sera we performed p24Ag and HbsAg detection, with and without prior dissociation of CIC, we determined serum level of CIC and immunoglobulin classes IgM and IgG level in sera and in polyethilenglycol (PEG) precipitates of sera. Acid dissociation of immune complexes revealed a high proportion of HIV antigen positive sera in all stages of HIV disease progression. HbsAg in serum of HIV positive patients was also found coupled in immune complexes much more frequently than in the HIV negative control group. In many instances both antigens were simultaneously found coupled in CIC. Immune complexes detected have been shown to contain both IgM and IgG immunoglobulins, while IgM antibodies were associated to immune complexes in higher proportion than IgG, compared to total serum immunoglobulins.